How much water can I collect?

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By knowing the square footage of the catchment area or roof, we can calculate how much rain is collected for the inches of rainfall at any given time for your rainwater collection system. Total up all areas of the roof surface that feed into collection gutters. Be sure to include porches, overhangs, garages and any other roof surface. Every square foot counts! Simply type in the square footage and a number for Inches of rainfall over a time period you wish to calculate.

The best way to know how much water a household uses is to look at previous water bills per month. However, for places not on city water and primarily served by well, calculating water use can be a bit trickier. This calculator is based on an average daily use of water per person for common activities. We have added in additional factors for high water use activities that can be variable to different households and lifestyles. Simply fill in the fields and this calculator will give you an idea of how much water your household uses.

Properly sized water storage capacity is critical to capture as much water as possible and anticipate future water shortages. This calculator uses the information gathered in the two previous calculators. You will first put in your square footage of catchment area and a starting amount of water that you may already be storing. This can be 0 if it is an unfilled new system or not installed yet. The calculator is pre-loaded with monthly inches of rainfall based on published totals from 2021 in the central Texas area. These numbers can be manually changed as well to look at how changes will affect your specific household. Enter monthly useage totals from the Water Useage Calculator earlier. The calculator will display monthly water collection and how much water is left over for the month after useage. Your maximum water storage capacity needed will be the amount of water leftover from the previous month combined with water collection of the current month.