Rain Harvest Calculator - Free Planning Tool for Designing Rainwater Harvesting Sytems

Instructions
Use the input fields below to define your rain collection system. The graphs and data table refresh automatically as calulator inputs are changed. Mouse over the the table and input labels as well as the graph data points for additional information. Only selected USA locations have automatic population of the rainfall data via the Location input. For all other locations, manually enter the monthly rainfall amounts in provided inputs.

The following URL will allow you to return to this page with your selected calulator values:

Location* (Enter Location Name or Select from List)

Rainfall % of Normal

Collection Area (sqft)

Collection Efficiency

Tank Capacity (gallons)

Starting Amount (gallons)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Rainfall (inches)
Supplement (gallons)	Apply to All
Usage (gallons)	Apply to All

													Total
Normal Rainfall
Adjusted Rainfall
Captured Amount
Supplemented Amount
Usage Amount
Inflow/Outflow Amount
Tank Level													-
Overflow Amount
Shortage Amount

NOTE: US Gallons (3.785 litres) are used when calulating volume.
* The NCEI 30yr Normal Monthly Rainfall (1981-2010) dataset is the source of the location specific rainfall data