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What Kind of Pump is Used to Transfer Water Stored in Rainwater Collection?


This is Part 7 in the series “How to Build a Rainwater Collection System”. Click to see partsone,two,three,four, five and six.

Submersible water pump with float switch and control box.Either a submersible pump or centrifugal pressure pump will be required to transfer water from storage to filtration and use. A submersible pump will need means of regulating flow.

A pressure tank with a pressure switch will tell the pump when to turn on and off by a drop of pressure in the pressure tank. This application is much like well system and is intended for household use. It could be used for irrigation, but keep in mind that the pressure tank will need to be frost protected.

A stainless steel cylindrical gas heater with a black front.The most common method of conveyance would be a booster pump. These pumps are generally centrifugal pumps and can be placed in the mechanical room or well shed. A centrifugal booster pump is used without an exterior pressure tank and is considered an “on demand” pump, meaning that when the faucet is opened, the pressure in the pump drops down to low pressure – usually 20 PSI, and the pump will start running and maintain constant pressure while the faucet is open. Once the faucet is closed, the pump will continue to run until it meets its high pressure cut off.

Either pump system should always be used before filtration and disinfection — which will be our next topic.

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Concerned With Aesthetics of Above Ground Water Storage?


This is Part 6 in the series “How to Build a Rainwater Collection System”. Click to see partsone,two,three,fourand five.

Rows of blue plastic-covered plants on a rocky shoreline.Are you concerned with the aesthetics of above ground water storage? Then underground storage may be right for you.

Underground storage tanks need to be structurally engineered to withstand the inward pressures of back filling and compacting. Most will need to be weighted down so ground water will not “float” the tank when empty. It is advised that a curtain drain be installed at bottom of excavation to allow excess ground water to drain away for the same reason.

Buried tanks can be fiberglass, plastic, and cement. Large sizes (over 2,000 gallons) tend to be fiberglass, while smaller plastic tanks (up to 2,000 gallons) can be manifolded together to achieve the desired capacity. Cement tanks should be lined with a poly liner and “mono poured” when constructed.

Other specialty tanks consist of modular which are may be buried and bladder or pillow tanks that can be placed in crawl spaces.

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How to Build a Rainwater Collection System – Part 5


This is Part 5 in the series “How to Build a Rainwater Collection System”. Click to see partsone,two,threeand four.

A large silver water tank beside a brick building.Steel water storage tanks for rainwater collection are generally bolted together grain silos adapted for this use. Made of galvanized corrugated steel panels, wall panels average 17 – 20 gauge with the galvanized roof panels being high rib or flat seam with a center hatch at the top and an access hatch near the bottom of the roof. A felt pre-liner is used between the steel and the main liner to protect it from abrasion. Liners are usually polyethylene and NSF approved when used for potable application or PVC, which is generally used for non-potable. However, PVC can be used for potable, as long as it is NSF approved. RainBank recommends polyethylene for this application.

Steel tanks need to be built on a engineered cement slab with hold-down anchor brackets designed for the seismic zone where the tank will be placed. Plumbing for overflow, suction, discharge and any cross over lines used in multiple tank applications can either be PVC flanges, polyethylene or PVC boots if coming up through the cement slab. If penetrating through the side of the wall panels, PVC flanges will need to be used.

A metal-roofed, cone-shaped greenhouse surrounded by greenery.Steel water storage tanks offer durability and protection of the liner from UV rays, plus offers an industrial or rural architectural look. Many commercial applications use this type of storage for both of these reasons. Overflow lines can be installed on the outside of the tank, but it is recommended that any pressurized lines be underground and frost protected in our Washington climate.

Accessories include exterior ladders, platforms, and level gauges. The galvanizing does not need painting although if properly prepped, tanks can be painted to suit.

Assembly can be difficult for the homeowner or contractor, so it is recommended that a trained installer with the proper tools and knowledge be used.

Are you interested in building your own water harvesting system? Leave a comment below.