Rain Barrel Calculator

Calculate rainwater collection potential from your roof. See water bill savings and barrels needed.

Roof Area Method
sq ft
Annual Rainfall
inches
Barrel Size

Annual Collection Potential

37,380 gal

From 1,500 sq ft roof with 40" rain

Monthly Average

3,115 gal

Barrels Filled / Year

680

Barrels Recommended

57

Annual Water Savings

$186.90

Environmental Impact

Water Conserved37,380 gal/year
Est. CO₂ Reduction75 lbs/year
Stormwater Runoff Reduced31,773 gal/year

Actual collection varies with rainfall patterns, roof material, and gutter efficiency (assumes ~90% capture). Check local regulations — some areas restrict rainwater collection. Rain barrel water is not potable without treatment.

Use the Rain Barrel Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.