Rainwater Harvesting Provides Irrigation at CHES

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At Carpenter Hill Elementary in Buda, Texas, we are fortunate to have two rain harvesters that collect rainwater and condensate from our air conditioners. This enables us to irrigate our landscaping and gardens without having to depend on potable water.

Each rain harvester holds 53,000 gallons of water.  That is about 218 tons of water each.  As you can see above, the rain harvester is almost full in this picture.  Notice how the gauge is "upside down", i.e. the 1' marker is on the top and the 10' marker is on the bottom.  That is because as the water level rises, it contacts a float inside which rises with the water.  The red weight outside in the sight tube descends as the float inside rises, marking the water in feet.  Each foot is equal to about 5,300 gallons (53,000 gallons divided by 10').

Engineers have estimated that if our air conditioners ran constantly for twelve hours, they would produce 2,880 gallons of condensate.  When it comes to rainfall, we harvest rain from approximately 44,400 square feet of roof surface.  For each inch of rainfall, we get approximately 27,650 gallons of rainwater.  Thanks to the fact that we have a two-story building, there is enough head pressure to allow the tanks to fill from the bottom up.  This enabled us to bury the 6" water pipes as soon as they exited the roof rather than having them exposed to the elements.  They should last forever without needing to be replaced.

At Carpenter Hill Elementary, we are excited to be able to promote environmental stewardship through water conservation.