Rainwater harvesting/Rainwater harvesting calculators

According to a document from the EPA in 2013, the effectiveness of a rainwater harvesting system based on stormwater runoff management, adequate volume for stormwater retention must be ensured through consistent and reliable demand.[1] One way to calculate the optimum tank or cistern for this kind of scenario would be to compare the cost of the system, or the rebate received through applicable runoff reduction credits versus the reduction in overflow frequency for a certain size storm.


  1. Solloway, Chris. Rainwater Harvesting Conservation, Credit, Codes, and Cost Literature Review and Case Studies. Environmental Protection Agency, 2013.