Cistern
How much does it cost? On the low end, an 800-gallon cistern can cost anywhere from $500 to $1,000, depending on the material you choose. On the high end, an extra-large cistern with a 20,000-gallon capacity and structural concrete foundation can cost up to $20,000, not including the labor to install it. Large-scale, high-end cisterns are usually used for offsetting the amount of potable water used inside the home and for the landscape and need to be designed in consultation with an architect and engineer. An underground cistern requires excavation, which also adds to the cost. Underground cisterns are designed on a case-by-case basis and in consultation with an engineer and landscape architect.
Why use a cistern? One advantage of choosing a super-sized cistern over a rain barrel is that it lets you store more water, resulting in a greater benefit to watershed health. Cisterns and rain barrels can be used in conjunction with other sustainable stormwater techniques in the landscape, such as rain gardens and swales. When evaluating whether to choose a cistern over a rain barrel, consider the following: ProsCisterns store more water for longer periodsPotential to add additional cisterns later if space and budget allowPotentially eliminate the use of potable water irrigation for your entire landscapeCan be integrated with greywater reuse systems to reduce your home’s overall water useCan be installed underground or above groundConsRequire a large amount of spaceLarge initial investmentRequire professional installation help because of their sizeCisterns over 5,000 gallons in capacity also need structural support at their baseProhibited in Colorado; instead you can redirect roof rainwater to a rain garden for infiltration
Where to place your cistern. Placement should be done in consultation with your architect or in consultation with your landscape architect if the cistern is for storing roof runoff. Some general guidelines are as follows:Check with your local building code on setbacks and regulations. A cistern will probably be treated as a “landscape structure” and may require a permit.The most cost-effective location will be closest to the source point for the water to be stored — for example, next to a downspout that collects roof runoff.It’s easiest to place the cistern uphill from where the water will be used. This eliminates the need for pumping the water, allowing gravity to do the work for you.
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