31 Jul Types of Rainwater Storage Tanks
Rainwater is one of our most valuable resources, too often taken for granted. Consider for a moment the rain that falls on your roof. Half an inch of rain on a 2,500 square foot roof equates to 778 gallons of water. In a region where the annual rainfall is 20″, that’s 31,120 gallons of water. What could you do with that free water?
For drought-ridden states like California, Arizona, and Texas, harvested rainwater may be the only water available for landscape use. For other areas, harvested rainwater may mean financial savings of hundreds or thousands of dollars.
Eleven states have taken on the issue of water harvesting and use:
States are enacting legislation covering everything from capital funds available for municipal rainwater harvesting projects to tax incentives for homeowners who install collection equipment. Texas leads the way by promoting rainwater harvesting for residential, commercial, and industrial use, as well as publishing detailed guidance on rainwater harvesting systems technology. Rainwater harvesting equipment is tax exempt. And in arid areas of the state, rainwater harvesting is mandatory for all new state buildings of a certain size. Harvested water can be used for potable (drinking water), as well as non-potable indoor and outdoor uses.
*Note: Check your state and city regulations on water capture. The NCSL published State Rainwater Laws & Legislation update in February 2018.
See also: Rainscapes – Landscape Design
Types of Systems
Basic Rainwater Capture
The most basic system is also the ideal starter system for homeowners. It consists of a stand-alone tank or rain barrel attached to gutter downspouts. Rain barrels are set up on a platform to allow gravity feed of the water. Multiple rain barrels can be connected to create a linked system.
Complete Rainwater Capture System
A complete system follows rainwater’s journey, from catchment to its final destination. Filters are installed at the entrance of downspouts or across the entrance to collection tanks.
Larger systems feed high capacity underground storage tanks with submersible pumps. Filters and sterilizers remove impurities and kill harmful microorganisms, producing potable water. And any water overflows are directed to a backup cistern.
Rainwater capture and usage restrictions may apply, check local water capture and storage regulation in your area.
Rain, Rain, Go Away
Conversely, many parts of the country, like the Pacific northwest or tropical Florida, experience predictable rainy weather. If you live in an area with less regular rainfall, but the rain tends to come in “events” with flooding (parts of Texas or Oklahoma, for example), you’ll simply need to be aware of when sudden rains are coming in order to batten down the hatches. Rainwater storage systems can be just as useful in a drought-prone area as well as one that floods or sees a lot of rain. They can also help take pressure off of your garden, catching water that could drown your plants and save it for dry spells in the summer months.