Rain barrel first-year cost estimator
Enter roof catchment, local rainfall, and barrel count. You get honest DIY vs kit USD ranges for year one, plus a rough gallons estimate. No account. No email. Runs in your browser.
Not a substitute for the free legality card or local code. Numbers are typical U.S. suburban ranges (2024–2026 street prices); your county and big-box aisle will differ.
Your setup
One downspout’s share of roof — not always the whole house. Garage wing ~200–400; modest house slope ~600–1200.
30″
Use your local normal (NOAA / Extension). Dry West often 8–18″; humid East/South 35–55″; PNW coast higher.
Typical starter: 1–2 × ~50–55 gal. More barrels ≠ more roof; they only store what the roof delivers between storms.
80%
80% is a calm default. Drop toward 60–70% if gutters clog, first-flush dumps a lot, or screens are coarse.
DIY assumes food-grade drums + bulkhead/spigot/diverter. Kit assumes consumer barrel kits from big-box / online.
Gravity feed needs no pump. Add a pump only if you must lift water uphill.