How Much Rainwater Can I Collect From My Roof?
- June 15, 2018
How much rainwater can you harvest from your roof?
With only one inch of rainwater, you can collect around 600-gallons off of a 1,500-square-foot roof every time it rains. Using rainwater collection as a water source has been done for thousands of years, with many states have a resurgence of sustainable practice. In some areas, there are financial incentives and rebates available.
> In Texas, rainwater systems are tax-free. Learn More
> California just passed an amendment to start excluding rainwater systems for property tax reassessment starting in January of 2019. Learn More
> Homeowners in Tucson, Arizona are offered rebate incentives to implement rainwater systems. Learn More
The basic equation of calculating how much rainwater you can collect off of your roof is the catchment area (ft 2 ) multiplied by the rainfall depth (inches of rain) multiplied by a 0.623 conversion factor.
There are many factors that affect this, including what materials the roof is made of, the slope of the roof, and the rate of the rainfall.
The Texas AgriLife Extension Office has created an extensive spreadsheet calculation that breaks down rainwater collection by the month. Link
Harvested Water (gal)
=
Catcment Area (ft²)
x
Rainfall Depth (in)
x
0.623 Conversion Factor
To Calculate the Rooftop Catchment Area
Calculating the square footage of the rooftop catchment area can provide you with an estimate of how much rainwater you can collect, and how much you need to prepare to store.
The size of the catchment roof area is based on the “footprint” of the roof, which can be calculated by finding the area of the building and adding the are of the roof’s overhang.
The below image shows how the difference in roof slope doesn’t always change a building’s catchment area.
Contact your local Pioneer Water Tanks Dealer
Pioneer Water Tanks America operates with a network of accredited providers and installers for localized service.
Call or fill out the contact form to be connected with the closest provider today.
For advice on setting up a rainwater harvesting system, contact the team at Pioneer Water Tanks on (877) 223-7784 or fill in our form to enquire online.
