This Microsoft Excel-based calculator compares the water use and cost of a sub-surface drip irrigation system (with rain-shutoff device) to conventional sprinkler irrigation. The only inputs are: irrigated area, water rate cost, length of growing season, number of days per month with over 1/2” of rain, and frequency of irrigation. Outputs include: initial cost, annual water use, annual water cost, average annual maintenance and repair cost, and lifetime costs for both systems. The calculator yields low and high estimates for each, based on national averages. Users have the option to input their own cost data.
https://archive.epa.gov/wastes/conserve/tools/greenscapes/web/html/index-2.html
