Click on the number on the house to see description of that section of the system.
The first “component” of a rain water harvesting system is the collection surface, typically a structure’s roof. Though opinions differ somewhat, there are a few general rules to collection surface materials and configuration that should be considered. Clay tile roofs seem to afford the greatest benefit to rain water collection. They support water flow very well and don’t add any impurities to the water. Clay stays relatively clean as its surface is good at shedding debris. Unfortunately, clay tile roofs are not widely used for home construction in the Midwest and many other states. They can be quite expensive.
Of more common construction, painted steel standing seam roofs are the next best choice. This roof type encourages laminar water flow and adds nothing to diminish water quality. It must be emphasized here that the steel must be painted! Bare galvanized steel, or any other bare metal for that matter, should never be used as a rain water collection surface if the intent is to re-use the water. Bare metals will change the quality of the water and require specialized filtering.
Asphalt or fiberglass shingled roofs are very common and will do well on a collection surface. There had been some argument in the past concerning the oils embedded in the shingles leaching into the water. After much debate and testing it is somewhat accepted that the amount of oil leaching is minimal and of little significance. Also, proper re-use techniques avoid the top 6″ and the bottom 6″ of water in any tank. This helps negate the effects of any type of impurity that doesn’t remain in solution or differs greatly from the specific gravity of water.
Roofs to avoid in addition to unpainted metal roofs include wood, cedar shake, rubber, asphalt and tar paper. If you don’t see your collection surface discussed here, send us an email or give us a call.
Beyond collection surface material, architecture and roof construction should be considered. High peaked or heavily slanted roofs are the best. These tend to remain cleaner during periods between rain events and direct water to the gutters more efficiently. Low peaked roofs may require additional filtering before the water enters the tank. Flat roofs should be avoided. Flat roofs are typically coated in tar paper, asphalt, oil or rubber and gravel. None of these are acceptable and the flat roof tends to accumulate a lot of debris and impurities. Flat roof filtration requirements can be a nightmare and re-use opportunities are quite limited. Flat roofs can be considered if the project entails storm water management only and there is no re-use planned.
2. Gutter Protection:
Most collection surfaces utilize a gutter as the first component of the “conveyance system”. This is the first place where the rain water is actually collected and directed to a specific location. Gutters themselves can add to the impurities of the rain water if not properly protected. Debris, bird waste, bugs and leaves can accumulate in gutters creating a breeding ground for bacteria and insects. So our first line of defense in preserving the inherent purity of the rain water is to install adequate gutter protection.
As you know there are literally hundreds of gutter protection products out there – all claiming to be the best. We can’t possibly review all of them, but RHSC has done some in-house testing and we’ve developed our own preferences. There is one thing consistent in our testing and all the independent test results we’ve seen: there is NO gutter protection product that is maintenance free. Don’t listen to anyone who claims otherwise. There is not a single product out there that can accommodate every kind of debris that may fall onto a roof.
In our opinion, the most expensive is not necessarily the best. Without naming specific brands, the “cover” types of protection do a great job of diverting large debris over the gutter and onto the ground. The problem we find is that they can waste a lot of water in the process. They also incorporate a rather large space between the bottom of the cover and the top edge of the gutter. This gap, as much as ½”, allows an unacceptable amount of large particle debris into the gutter.
On the other end of the spectrum are the screen types of protection. Depending on the screen opening size, each of these products have performance problems. The least expensive “big box hardware store” products do fairly well but are susceptible to allowing large particles entering into the gutter including pine needles, oak tassels, maple “helicopters”, small twigs and leaves. As screen size gets smaller, many of these problem items will slide over the screen. However, the smaller screens can clog with tiny particles embedding in the screen itself and eventually clog to where the water just flows over the edge and onto the ground. We have also found that the small mesh screens are susceptible to freezing up much more quickly than those with larger openings.
We have found a product we like which is actually a combination of the cover and mesh technologies. We’ve tested this product and found it does well with debris removal but also encourages the capture of substantially all of the water and directs it into the gutter. It is also quite reasonably priced. The product name is Premier Gutter Cover. A photo sample of this product appears on this page or you can link to their website by clicking on the company name.
Whatever product you decide on, realize that periodic cleaning will be necessary. How “periodic” depends entirely on your particular setting. Do you have a lot of trees nearby? What is your sun exposure? Is there a lot of wind in your area and how are your roof slopes positioned in relation to wind patterns? Do you have steep or shallow roof construction? Do not underestimate the importance of this “first line of protection”. It will save a lot of filtration cost and clogging headaches in the future.
3. Outlets and Collectors:
From the gutter, water is usually channeled via an outlet fitting. This outlet directs the water into a downspout or directly into a filter/collector assembly. If into a downspout, the water continues downward until it eventually exits into a filter/collector assembly or just a collector.
There are many types of rainwater collectors or more properly called “diverters”. These should not be confused with “first flush diverters” which serve an entirely different purpose (as explained in number 5 below). Water diverters are usually cut into a downspout to re-route the water into a barrel or water tank. These are used primarily for very small rain water harvesting systems. They are easily installed and are simple in nature. A few examples of diverters are shown below.
Outlets can vary in size and configuration depending on gutter size and anticipated water flow. These are usually provided by the gutter installer as part of the gutter installation process. In some cases, you may want to prevent water from dropping down through one downspout and move it to another, more convenient downspout on the same gutter span.
For round downspout applications a device known as “Rain Gain” can be used. It is placed around the outlet of the gutter you are wishing to avoid and creates a “dam” that prevents the water from flowing into the downspout. As the water level in the gutter begins to rise, it flows to another downspout elsewhere in that gutter run. Extreme caution should be exercised when using this product. Too much water in a gutter can become very heavy and may damage a marginal gutter installation. Also, this can leave water in the gutter for prolonged periods of time encouraging debris build-up and bacteria growth. Rain gain devices should only be used in circumstances where there is no other choice for downspout access.
4. Inlet Filter Assemblies:
Primary filter assemblies (gutter protection) are extremely important when capturing rain water. The gutter guards will perform well in reducing large debris entering the conveyance system. However, additional filtering with insect prohibiting characteristics is necessary.
Filter heads, as they are sometimes referred to, incorporate finer mesh screen material in conjunction with larger surface areas to effectively rid the rain water of smaller suspended solids. These screens are typically of a size that prevents the passage of mosquito larvae and other contaminants. These filters are the real first serious cleaners of the water before it enters the rest of the closed conveyance system and storage tank.
There are many different types and styles of filter assemblies. Some are mounted directly under the gutter outlet as shown on the system design page. Most are located closer to the ground to facilitate periodic cleaning. Some are placed in the ground at the bottom of the downspout primarily for aesthetic reasons. These ground locations are only used when the storage tank is going to be buried.
Newer, improved designs of filter assemblies are constantly hitting the market. Fit and form are being designed in, to give them a more appealing look. Slanted screen surfaces are superior to flat surface screens. The slant encourages leaves, bugs, twigs and other airborne contaminants to slide off the screen, keeping the surface clear of debris. This self-cleaning attribute is well worth it when considering which filter head to use. Many heads incorporate easily removable screens for those times when a good washing is necessary to clear screen openings that have been plugged by tiny debris. Some examples of filter heads are shown below.
5. First Flush Diverters:
First flush diverters are another form of filtration. They deal with the dirtiest water off the roof and can help reduce chemical and bacterial contaminants. However, recent testing and research has indicated their effectiveness may be suspect and not essential in many rain water harvesting systems.
First flush diverters evolved from the scenario of long dry periods between rain events. The continent of Australia is one good example of their usefulness. In Australia, rain comes during only certain times of the year, and then comes in monsoon amounts. During the dry periods, roofs would tend to become layered with dust, dirt, decomposing insects, rodents and bird droppings. When the rains came, the “first flush” of water from the roof would be exceptionally dirty. First flush diverters were designed to divert this first flow of water away from the conveyance system and storage reservoir. A calculated amount of water would be wasted to prevent the contamination of the entire system.
Disagreement still exists on the proper calculation and formulae used in determining how much water to divert. It all becomes a function of the environment surrounding the particular site under consideration. Roof construction, weather patterns and the system designer’s preferences all come into play. Generally speaking, areas with regular rain falls and sites with open air environments typically don’t require first flush diversion. However, it is always a good idea to consult a professional before deciding whether or not to include one in your system.
If rainwater is to serve as the principal water supply for a building, or if it is the primary exterior water supply, then provision must be made to automatically switch to a backup water supply when there is insufficient rainwater to meet demand. We offer three different solutions that effectively isolate the two water supplies to prevent cross-contamination.
CISTERN BACKUP: The least expensive backup method is cistern backup. When the water level in the rainwater tank reaches a pre-set low level, a valve opens and water from the backup source is added directly to the rainwater tank. To prevent cross-contamination, the outlet of the backup water pipe in the tank must be several inches above the highest possible water level of the rainwater tank, or the backup water can flow through a funnel device that provides a similar air gap. Unfortunately, cistern backup creates the undesirable situation where potable-quality backup water is mixed with sediment-laden water at the tank bottom, producing a degraded mixture as the water supply.
The simplest cistern backup system utilizes a special mechanical valve with a weighted float at the end of a long cord. When the water level in the tank reaches the float, the valve opens and adds several inches of water. More sophisticated systems utilize a solenoid valve controlled by a low-voltage float switch or an electronic control device. Our commercial-grade solenoid valves offer the highest possible reliability for this type of backup. Unlike typical irrigation valves, they feature high-efficiency solenoids, stainless-steel actuators, and brass shock cones. If there is a power failure, they automatically shut off water flow. We stock 1″ and 1-1/2″ sizes.
DIRECT BACKUP: The most reliable backup method is direct backup in which both the backup source and rainwater supply directly connect to the plumbing system through a motorized three-port valve. When there is sufficient water in the rainwater tank, the valve connects the rainwater supply to the plumbing system. When the water in the rainwater tank reaches a pre-set low level, the valve connects the backup water supply to the plumbing system. A reduced pressure backflow preventer is used between the backup supply and the valve to assure there is no cross-contamination.
We offer a wide range of industrial-quality three-port ball valves that are ideal for rainwater systems. The valves are directly coupled to a weatherproof low-wattage 24vac electric actuator. When power is applied, the ball rotates 90° in one direction; when power is reversed, the ball rotates 90° in the other direction. For building water supply systems we offer an optional internal battery that automatically connects the valve to a public water supply backup in the event of a power failure to assure pressurized water will always be available for toilet flushing and other critical water uses. We can supply 1″, 1-1/4″, 1-1/2″, and 2″ valve assemblies in brass or PVC.
Our newest solution for direct backup is our “Hydraulic Backup Valve”. This valve operates via mechanical and pressure differential design. Electrical signals via a control system are not required. This valve is currently available in 1″ NPT ports. It can be mounted in any position and is constructed of nickel-plated solid brass.
FLOAT TANK BACKUP: The safest backup method is float tank backup, named for a small wall-mounted tank that contains a float valve. When there is sufficient rainwater, an external pump draws water from the rainwater tank by way of a three-port valve and delivers it to the plumbing system. When the rainwater tank is low, the three-port valve switches so that the pump draws water from the wall-mounted tank. As the water level in this small tank drops, a float valve inside the tank opens and refills the tank. The tank has a primary overflow that is directly plumbed through a trap, as well as an upper emergency overflow that simply dumps water if the primary overflow ever gets clogged. This assures there will always be an air gap below the float valve, providing absolute protection from cross-contamination.
Our residential float tank system consists of a fully-automatic external pump mounted on top of the float tank. The pump draws backup water from the float tank through a 120vac multi-port valve attached directly to the pump. A float switch running from the valve to the rainwater tank switches the three-port valve between the two water supplies based on the rainwater level. When combined with a pre-filter and storage tank, this serves as an all-in-one rainwater pumping and backup system suitable for operating a residential-scale rainwater system with peak flow rates up to 15 gpm. We also custom fabricate larger systems for commercial applications requiring significantly higher flow rates and programmable controls.
7. Tanks, Cisterns and Barrels:
The most commonly recognized component of a rain water harvesting system is perhaps the storage tank. From the very smallest of rain barrels to the largest of fiberglass tanks and modular units, this is where the water rests, waiting to be called upon to perform some task or just be slowly released for storm water control. The tank is also the one component of the system that you can find literally hundreds of designs, styles, colors and materials. Some are made for above ground use, in-ground burial, non-potable and potable re-use. Some aren’t even really “tanks” at all as they are designed to slowly release the water through ground infiltration or storm sewer conveyance. Whatever your need, there is a tank for you!
We will try to cover several types of tanks, cisterns and barrels. It is a good idea to be familiar with the choices that are out there when considering the components for your rain water harvesting project.
Above ground tanks provide the most choices. They start with the simple round 55 gallon recycled food products drums. Do not use a drum that was not originally used for food grade products. Inks, oils, stains, paints, and lots of other chemicals can leach into the drum material and later bleed out into the water you store in it. Aesthetic demands have opened the door to hundreds of manufactured rain water harvesting “drums” and small volume tanks. Some are made to look like stone walls or fences and serve a dual purpose. Some are fitted with a trellis to accommodate plant growth and blending with the environment. Some are loud and crazy, lending their appeal to architectural design imagination! You can find many of these types of tanks on the internet as well as here on our website and in our catalog.
Once you get out of the 50 to 100 gallon range of barrels, storage tanks begin to take on a more “business” attitude. Large polyethylene tanks come in white, black, blue and green predominately. The darker colors are better for UV light resistance and will help limit bacterial and algae growth. Black tanks are the best and are usually made from a high percentage of re-cycled plastic for the sustainable minded buyer. White tanks are readily available and cheap to produce. Green and blue are usually designated as potable or special use tanks. Although poly tanks can be found in the sub-100 gallon category, they are more prominent in the 500 to 3,000 gallon range.
The next division of tanks would be corrugated steel tanks. These are primarily used for commercial, industrial and fire-fighting applications. However, many architects have found these tanks to be very appealing for small commercial applications as well as residential. In the commercial arena, they shout out: “hey, we capture rain water!” Some residential architecture is complimented with the old farm style steel cistern. These tanks are extremely rugged and will typically outlive the above ground poly tank (which is susceptible to UV light radiation). Steel tanks reflect sunlight keeping the interior dark and the water cooler than other tanks. They also are built with PVC liners making them useable for potable water applications. Steel tanks are not cheap, but if you are in it for the long haul you should seriously consider one. They are shipped in pieces and require assembly, usually by someone trained by the factory. They require a concrete pad or equally supportive flat level surface to sit on. Each tank is usually engineered for the particular application.
As mentioned previously, there are a number of specialty tanks being manufactured. These have been developed and produced to accommodate a few more specific elements than just holding water. There are three that we have found to be rather interesting and in one particular case, quite popular.
The first is a “corner” tank. This is our most popular, entry level residential tank and comes in a 50 and 95 gallon version. It is made of recycled plastic, incorporates UV light stabilizers and is designed to fit right up to the corner of a house. It is a “turn-key” product in that the self-flushing inlet filter/strainer, overflow and multiple outlet options are all included in the design. You just set it up against the house corner (on a firm foundation of concrete construction blocks), cut your downspout to fit and use the cut piece of downspout as the overflow. The plastic material is molded to accommodate painting the barrel to match the house. Most other small barrels will not hold paint for very long.
The second unique product is known as a “Rain Column”. This product is 7′ tall and 24″ in diameter. It incorporates a top filter and access lid. Various outlet configurations accommodate overflow and add-on capability. Tank capacity is 150 gallons. But the big surprise is that there is a trellis available that attaches to the flattened side of the tank. This allows plants and vines to grow over the tanks, completely blending them into the landscape.
Another above ground tank we really like is the “SuperBarrel” and its big brother the “Hercules”. These tanks are 350 gallon and 430 gallons respectively. They are manufactured in halves and transported nested together. This really saves on shipping and handling. The half dimension has been intentionally held to 32″. This allows passage through a standard doorway if you want to use them in a shed, outer room or basement. The halves are mated via a rubber gasket when assembled. The Hercules can even be used underground.
The second major category of tanks is the underground or in-ground. Here we also have a multitude of choices. Because of excavation costs and handling, these tanks aren’t usually found below 500 gallons. The most popular sizes are 1,000 and 2,500 gallon and are manufactured of polyethylene plastic. Concrete tanks are popular in large commercial applications as are fiberglass.
Deciding which to use usually comes down to designer preference or cost. Certain materials are acceptable for potable water projects and others should be avoided. All will suffice for irrigation re-use. Larger tanks require expensive transportation and crane handling. Several smaller tanks that can be transported more economically and easily handled on site may be a better choice than one large tank of equivalent capacity.
Beyond one-piece molded or manufactured tanks are the “modular” tank systems. These are gaining popularity not only for re-use systems but for storm water management projects as well. Sometimes these are referred to “milk crate” systems as many of the early generation modular units resemble oversize milk crates. Newer versions have evolved that are not as confined in design and bring additional advantages to the modular concept.
The units themselves are typically assembled on site from various flat molded plastic plates. Some incorporate pieces that are more three dimensional in shape, but are designed to nest into each other for efficient shipping and handling. Most of the assembled units vary in size from 20 to 60 gallon capacity. Dimensions typically run in the one to three foot range. They are quite light and easily assembled and moved about by one person. These units act as the support structure for an impervious liner that is wrapped around the unit assemblies to form a custom sized and configured tank.
We have taken a liking to one specific brand of modular unit. In our catalog it is known as “RainCavern-C”. The base product is a modular unit measuring 2′ x 2′ x 2′, creating a capacity of 56.5 gallons. The greatest benefit of this particular product is the molding of 18″ diameter openings on every face of the “cube”. This accommodates future inspection and cleaning of the tank. No other modular unit system offers this accessibility. Also, the 2′ x 2′ x 2′ dimensions help in the overall design process, simplifying calculations of excavation requirements.
The complete modular tank system requires additional components. A liner is required as well as cushioning fabric to protect the liner. The type of liner is critical and dependent upon the re-use intended. Certain liner materials such as PVC require special processes during fabrication and construction of the tank system. These types of tanks should be left up to the professional to design and install. Visit our Products Page for examples of all types of tanks.
8. Tank Overflow:
All tanks, whether Inground or above ground require some form of overflow. For in -ground tanks, the overflow is typically piped underground, carrying overflow water to a lower elevation. Above ground tanks can have the overflow above or below ground. Both overflow systems should be designed utilizing only gravity to carry the water away from the tank location.
The size of an overflow pipe is determined by the size of the inlet pipe. The overflow pipe size must be at least as large as the inlet to ensure maximum flow discharge. The water carried out through the overflow typically will not require any type of filtration unless discharge regulations mandate.
9. Conveyance Systems:
Once the water has been filtered to “mosquito clean”, it usually enters the main portion of the conveyance system. Technically speaking, the full conveyance system begins with the roof surface and includes all aspects of gutters, guards, filters, first flush diverters, downspouts, piping systems and anything else before the water actually hits the storage tank. However, when breaking parts of the system, these other components serve vital roles as stand-alone products. The conveyance piping is typically thought of as the network of fittings and pipe that get the water to the tank.
There are many choices of pipe and fittings available and some sort of standardization has been developed. Only smooth interior pipe of a quality that doesn’t bleed into the water should be used. Our recommendation is to utilize schedule 40 PVC pipe in all installations. Some designers will look at this recommendation as a waste of money since this pipe tends to cost more than alternatives such as SDR35 PVC pipe and thin-wall drain pipe. We look at it from a position of safety and long term benefits. Schedule 40 PVC pipe is very strong and thick walled. It requires no “bedding” when buried as SDR35 does, so labor intensity is reduced for in-ground installations. It is abrasion resistant and holds up much better to abuse, rough handling and UV light reaction. The most important benefit we believe is that schedule 40 PVC pipe is the safest for water conveyance. It does not leach or bleed any chemicals into the water and provides the smoothest interior surface of all the other choices.
The conveyance system carries the water to the storage tank. This water has been filtered and cleaned as much as possible by the time it enters the final piping system. It is important that this part of the system maintain that cleanliness and purity. Although there will likely be additional filtration when the water is re-used, we certainly do not want contaminants or bacteria growth in the tank.
Although gravity flow can be used for flood irrigation, most other rainwater uses require pumping. Submersible pumps are installed within a rainwater storage tank, but most require a pump controller that cannot be submerged or flooded. Surface pumps are typically installed within a nearby building or pump enclosure.
SUBMERSIBLE TRANSFER PUMPS: RainDiver-Transfer pumps are low-pressure submersible pumps designed to be used with open-ended piping systems. Typical applications include transferring rainwater between slave and master storage tanks, transferring rainwater from sump pits to remote storage tanks, pumping excess rainwater from storage tanks where gravity flow is not possible, operating first-flush tanks, and emptying rainwater storage tanks. We offer 1/3 hp and 1/2 hp versions, both with rust-proof plastic housings, reliable oil-free motors, and stainless-steel shafts with ceramic seals. An automatic internal low-water shutoff float can be activated by lifting a knob on the top of the pump. In the automatic mode, they shut off at 1-1/2″ water depth; in the manual mode they can pump down to 1/4″ of water. Note that transfer pumps do not have sufficient pressure to directly operate irrigation or water supply systems.
SUBMERSIBLE PRESSURE PUMPS: In comparison with submersible transfer pumps, submersible pressure pumps deliver water at the considerably higher pressures required to operate irrigation or water supply systems. Our RainDiver-Pressure and RainDiver-Electronic pumps feature sturdy rust-proof plastic housings, reliable 1 hp oil-free motors, and stainless-steel shafts with ceramic seals. RainDiver-Pressure pumps require an external control system, such as one of our electronic pump controllers, to operate the pump in response to water demand and to protect the pump from running dry. In contrast, RainDiver-Electronic pumps have integral electronic pump controllers so no other controls are necessary. RainDiver-Electronic pumps are also available with a choice of intake systems: either a stainless-steel intake screen or stainless-steel ring with a 1″ threaded pipe fitting for use with a floating extractor. Both are sufficient to operate typical single-family residential irrigation or water supply systems.
Our RainDiver-Pro professional line of submersible pressure pumps feature heavy-duty stainless-steel housings, water-cooled motors isolated with double ceramic seals, stainless-steel shafts with oversized bearings, and 48 foot power cords. We offer two versions: one with a slotted bottom intake (S-version), and one with a sealed stainless-steel base that includes a 1-1/4″ threaded pipe fitting for use with a floating extractor (T-version). Both are available with 1/2 hp, 1 hp, or 1-1/2 hp motors with flow rates and pressures sufficient for single-family residential, multi-family residential, and commercial rainwater systems. All RainDiver-Pro pumps require an external control system, such as one of our electronic pump controllers, to operate the pump in response to water demand and to protect the pump from running dry.
SURFACE PRESSURE PUMPS: Surface pressure pumps, like submersible pressure pumps, are used when rainwater directly supplies irrigation or water supply systems requiring water pressures of 40 psi to 70 psi. Our entry-level pump is the RainSpring-Pressure, a self-priming surface pump featuring sturdy plastic housings and reliable totally-enclosed 1/2 hp or 1 hp motors. For higher flows and pressures we offer the RainSpring-Pro, a commercial-quality self-priming pump with stainless-steel housings and a choice of 3/4 hp single phase, 1-1/2 hp single-phase or 1-1/2 hp three phase totally-enclosed motors. For larger commercial systems, we offer the three-phase 2.5 hp RainSpring-HiFlo, a heavy-duty, super-efficient vertical pump (not self-priming). All surface pumps should be used in conjunction with an in-line pre-filter or floating extractor and appropriate external pump controllers.
AMPHIBIAN PUMPS: Amphibian pumps can function either as submersible or surface automatic pressure pumps, but add features not found in either. They can be exposed to the elements without rain protection, enclosed in underground vaults without ventilation, or fully submerged. Sophisticated internal electronic circuitry turns the pumps on and off in response to water demand without the need for pressure switches or pump controllers, engages automatic dry-run shutdown when there is no pressure or flow, and provides anti-lock shaft rotation when the pump is inactive for an extended period.
We offer two versions. The Amphibian-J125 is a 1-1/4 hp self-priming jet pump with a stainless-steel motor housing, techno polymer suction and control ends, and a noryl impeller. The Amphibian-M125 is a 1-1/4 hp high-flow multi-stage pump with a 100% stainless-steel shell, brass bearing supports, and a stainless-steel impeller. Amphibian-M125 pumps are not self-priming and are not recommended for use where the water level is below the pump. Standard features include oil-lubricated ceramic/carbon seals, 48 foot power cords, and calibrated external check valves.
AUTOMATIC PUMP CONTROLLERS: Automatic Pump Controllers make it possible to operate a rainwater system without a large pressure tank, pressure switch, and float switch. In the simplest design, the bottom inlet connects to the pump, the top outlet connects to the plumbing system, and the pump is plugged into the controller which is in turn plugged into an electrical receptacle. When a faucet is opened, the controller senses the drop in line pressure and instantly turns on the pump to re-pressurize the line. If no water is available, the controller shuts down the pump to prevent dry-run damage.
We offer four pump controllers. The low-cost PumpControl-Compact is a 1″ controller that is ideal for use with our consumer RainDiver-Pressure and RainSpring-Pressure pumps. For our professional pumps we recommend the basic PumpControl-Simplex, or our most advanced single-phase controller the PumpControl-PF that features a built-in pressure tank and digital monitoring of pressure, current, and motor power factor. For three-phase versions of the RainDiver-Pro, RainSpring-Pro and RainSpring-HiFlo pumps, we offer the variable-frequency drive PumpControlPro-VFD.
FLOATING EXTRACTORS: Even with effective pre-filtration, fine sediment accumulates at the bottom of a rainwater tank and organic debris floats at the water’s surface. A floating extractor is a device designed to draw the cleanest water in the tank which lies just below the surface. It consists of a screened intake attached to the end of a suction hose and suspended from a float. The float rises and falls with the tank water level, so the screened intake is always in the same position relative to the water surface. Our floating extractors use stainless-steel intake screens with larger openings than our pre-filters, so they are unlikely to clog. Standard sizes are 1″, 1-1/4″, 1-1/2″, and 2″. For the 1″ size we also supply a dense self-sinking intake hose to prevent air locks from blocking flow to the pump.
11. Re-use Filtration and Treatment:
Rainwater from a properly designed rainwater pre-filtration and storage system can be used without further treatment for landscape irrigation, garden ponds, and most exterior applications. When rainwater is used within buildings, supplemental filtration is essential and disinfection is recommended. For toilet flushing and clothes washing, a sediment filter will remove suspended solids which can clog and damage valves, and an activated-carbon filter will remove dissolved organic matter which can cause discoloration and odors. For showering, hand washing, or drinking, use a high-intensity ultraviolet sterilizer to kill microorganisms that could cause illness. All filtration and disinfection components should be oversized in order to maximize performance and minimize maintenance.
PRESSURE FILTERS: We offer exceptional quality pressure-filter housings that accept standard 4.5″ x 20″ sediment or activated carbon cartridges. Unlike common filter housings, the filter pot is not twisted in place but rather is clamped with a large threaded nut. This makes disassembly easy, even after long intervals between filter element changes. A pressure-release button and a filter pot drain plug are supplied as standard items to facilitate filter maintenance without flooding. Either 1″ or 1.5″ pipe threads are available.
UV STERILIZERS: A typical UV (ultraviolet) sterilizer consists of a UV-emitting lamp mounted within a quartz sleeve (a special type of glass tube that does not block UV) which is in turn mounted within a stainless-steel tube. Water flowing between the quartz sleeve and the stainless-steel tube is exposed to UV energy which theoretically kills any microorganisms in the water. Better units also monitor the amount of UV energy that reaches the stainless-steel tube.
The design and operation of our UV sterilizer is completely different: two UV lamps and a quartz sleeve are all mounted inside a dry enclosure, one lamp on either side of the quartz sleeve. Water flows through the inside of the quartz sleeve and is exposed to UV energy emitted by both lamps. A sophisticated monitoring system measures the UV output from the lamps and compares it with the amount of UV energy that passes through the water. This approach exposes microorganisms in the water to significantly more UV energy, eliminates shadowing behind larger suspended particles, and accurately determines the exact UV exposure.
The problem with using typical UV sterilizers for rainwater is that although rainwater is a relatively high-quality water source, it can have elevated levels of dissolved organics, iron compounds, and phosphates that absorb UV energy. It is not uncommon to see the percent of UV energy transmission, called the UVT, drop below 70% to 75%, the minimum UVT required for ordinary UV sterilizers. Our high-intensity sterilizer is designed to disinfect when UVT levels are as low as 50%, a level rarely seen in rainwater.
Over time, the quartz sleeves in UV sterilizers become coated with a mineral deposit that inhibits UV transmission. The simplest UV sterilizers require periodic manual disassembly and cleaning, a difficult and messy process that occasionally results in a broken sleeve. Better UV sterilizers utilize a sleeve wiping device, but these are not completely effective and still require a regular maintenance schedule. UV sterilizers with UV monitors are also prone to problems caused by mineral deposits on the sensors which are exposed to water. Our UV sterilizer features a motor-driven internal wiper that requires no user action, and since the UV monitoring system in our sterilizer is not in contact with water it does not require cleaning.
For general rainwater disinfection, interior or exterior, we supply a version with 1″ ports suitable for flow rates up to 15 GPM and a version with 1.5″ ports suitable for flow rates up to 30 GPM. Contact us about sizing for drinking water systems. Both units include a sophisticated microprocessor-controlled monitoring system, a 24v output to operate an optional solenoid valve to stop water flow in the event of insufficient sterilization, plus an automatic bleed system to prevent overheating that can reduce UV output.
12. Measurement and Control:
To effectively manage rainwater utilization, it is important to know how much water remains in storage. We offer a variety of devices that use mechanical or electronic means to accurately measure and display the water level in a rainwater tank. The more sophisticated systems can manage backup and other rainwater system functions by operating valves and pumps in response to the measured water level.
MECHANICAL WATER LEVEL INDICATOR: Our Mechanical Water Level Indicator mounts directly into a hole in the top of surface storage tanks. A weighted float hung from a nylon cord rises and falls with the water level, causing a pointer to spin and accurately display the water level from 0 – 100″. Calibration is quick and simple: the cover is opened and the indicator ring is rotated to set the zero point. Its ultra-low cost makes it practical for the smallest tanks.
PNEUMATIC WATER LEVEL INDICATOR: Our Pneumatic Water Level Indicator is our least expensive remote-reading system. It can be mounted up to 150 feet from the tank and will accurately display the water level from 0 to 100% by measuring water pressure. The dial gauge must be mounted in a dry location, calibrated to the tank depth (up to 8 feet of water), and zeroed. Pulling a knob at the bottom of the gauge operates an internal air pump that clears any water in the hose and the tank probe. The water in the tank then exerts pressure on the air within the hose and probe in proportion to the water depth, which is displayed on the gauge.
This device is inexpensive enough to be affordable for any rainwater system and can measure in spaces with internal obstructions, including modular underground tanks where electronic devices require expensive pressure sensors to give accurate measurements. We supply a kit consisting of a dial gauge, a tank probe, a condensate trap, 100 feet of small-diameter hose, plus all of the fittings to connect everything together.
WIRELESS ULTRASONIC WATER LEVEL INDICATOR: Our Wireless Ultrasonic Water Level Indicator uses a directed ultrasonic beam to determine the water level in a rainwater tank and then transmits the data without wires to a display unit located in a building up to 1000 feet away. The water level is displayed as a series of eight lights, each representing approximately one-eighth of the tank height. Unlike more primitive ultrasonic devices, this unit features a high-power transmitter design that is unaffected by condensation plus sophisticated electronic circuitry to eliminate stray signals, preserve battery life, and warn of problems such as rapid water loss possibly caused by a leaking tank. The direction of the ultrasonic signal can also be adjusted to provide accurate results with domed tanks.
We supply a kit consisting of a tank unit, a display unit, two antennas, and batteries. An optional extension cable facilitates mounting the tank unit underground. Although ultrasonic units can be used in tanks made of any material, they should not be used in tanks with internal obstructions, such as modular underground tanks.
WIRELESS ULTRASONIC CONTROL SYSTEM: Our Wireless Ultrasonic Control System uses the same advanced ultrasonic technology as the Wireless Ultrasonic Water Level Indicator, but adds precision programming and display capabilities plus a wireless control unit. The wireless control unit can be located up to 1000 feet from either the display unit or the tank unit and will directly operate pumps or electric valves to provide backup, remote refill, or remote drain capability. Water level is accurately displayed digitally and the control unit functions can be easily programmed. Manual-override capability permits direct valve or pump operation when desired.
We supply a kit consisting of a tank unit, a display unit, a control unit, two antennas and batteries. Two versions are available based on the desired control unit: 24vac or 115vac. Note that power must be present at the site of the control unit to operate a valve or pump.
DIGITAL WATER LEVEL INDICATOR: Our Digital Water Level Indicator is an electronic device that accurately displays the water level in a rainwater tank from 0 to 100% using a radio frequency cable sensor that hangs in any open plastic or concrete tank. We supply a kit consisting of a digital display, a tank sensor, a sensor control box, and a power transformer. The display must be mounted in a dry location within 150 feet of the tank and wired to the control box mounted in the tank access way. The standard sensor measures tanks with up to 9 feet of water; an optional longer sensor measures tanks with up to 19 feet of water. Since the system is powered by a plug-in 24 volt transformer, an electrician is not necessary for safe installation. Due to the possibility of radio-frequency interference, this device is not recommended for use in steel tanks or modular underground tanks.
RAINWATER SYSTEM CONTROLLER: Our Rainwater System Controller is a state-of-the-art digital electronic device with a sophisticated microprocessor that accurately displays the water level in a rainwater tank from 0 to 100% and manages rainwater system functions based on water level or elapsed time. All system functions are accessible through an intuitive programming interface that can display in English, Spanish, or French. Output relays provide 24 volt power to operate a low-water backup system, a high-water transfer pump, a first-flush device, a filter rinsing valve, a service reminder system, or a variety of other rainwater system functions. We supply kits consisting of a digital control panel, the appropriate tank sensor and sensor-control box, and a power transformer. The control panel must be mounted in a dry location within 150 feet of the tank and wired to the control box mounted in the tank access way. Since the system is powered by a plug-in 24 volt transformer, an electrician is not necessary for safe installation.
FLOAT SWITCHES: When it is not necessary to know exactly how much water is in a rainwater tank, float switches can be used to operate a pump, valve, or other electrical device at a pre-set level. We stock mercury-free low-voltage (SPDT) and line-voltage float switches, as well as cable weights and transformers. Line-voltage float switches are provided with piggyback plugs for simple connection to 120v pumps.
MOTORIZED VALVES: We offer a wide range of industrial-quality motorized ball valves, both two-port and three-port, in both brass and true-union-PVC configurations. All valves have PTFE seats for durability and full-port designs for minimal pressure drop. Stock sizes are 1″, 1-1/4″, 1-1/2″, and 2″. We also offer 4″ and 6″ butterfly valves with glass-filled polypropylene bodies and bolted PVC flanges. All motorized valves use state-of-the-art 24vac operators sealed for external use. Operators feature electronic torque limiters, LED status indicators, internal anti-condensation heaters, internal limit switches, and manual overrides. An optional power-failure return insert is available to assure continuous water supply for rainwater systems serving toilets or other critical water uses.