I like to walk in the rain and watch the water running off the rooftops and into the downspouts of my townhome community. When it rains for a while, most of it drains into the parking lots and driveways, then into the streets. It seems like such a loss in a time of drought and climate change!
I was inspired to harvest rainwater, and my community’s Sustainability Committee took on the challenge. So far, there are four rainwater tanks installed on the site. We enjoy learning and observing the results. Water conservation is one result, when residents use the stored water for gardens and houseplants instead of potable (tap) water. Property protection is another; the tanks hold stormwater that could collect and ‘puddle’ near foundations and doorways.
A few lessons learned
Tank size: Location and budget determines size. Consider the amount of water that can be captured. How much rain falls on your roof areas during the year and during a monsoon event?
1 inch of rain on 1 square foot of surface = 6/10 gallon. 1 inch of rain on 1,000 SF = 623 gallons.
One of our downspouts could convey an average amount of 8,200 gallons of rainwater a year, though the drought has reduced the actual amount in recent years. Some people have told me that they bought a tank that was too small, and they wanted more storage capacity!
Overflow: Where does the extra water go when the tank is full? An overflow pipe with holes allows extra water to drain in a controlled manner. Swales and basins will slow water flow on a slope. Another tank can be connected to the first tank. Opportunities become apparent with observation.
Preparation: Build a foundation for the tank on a level surface. Our committee drew a plan for the first tank and used sand for the base, topped with pavers. Use concrete blocks to raise the tank’s height.
Purchase: We purchased our tanks from a local vendor who installed them with overflow pipes. The tanks are made by a local company with recyclable, food-grade polyethylene. Rebates are available to customers of the Albuquerque Bernalillo County Water Utility Authority for new rainwater tanks, depending on the size. Also look for the more integrated Rainwater Harvesting Landscape rebate.
The sound of rain in New Mexico is sweet. The sound of rainwater flowing into a tank changes as the tank fills up. Those sounds are even sweeter.