Yes. Rainwater collection is fully legal in Iowa, with no state limits on how much you can collect from your roof.
What Iowa law says
Iowa places no state-level restrictions on residential rainwater harvesting. You can install as many barrels or cisterns as your property supports, and no permit or registration is required. No state restrictions. As always, check for HOA covenants or local ordinances before installing a larger system.
How much water a Iowa roof can collect
Iowa averages about 34 inches of rain per year. On a typical 1,200 square foot roof at 85% collection efficiency, that works out to roughly 21,600 gallons a year currently running into your storm drain. A single one-inch storm delivers about 635 gallons, enough to fill 13 standard 50-gallon barrels.
Average annual rainfall in Iowa.
Gallons per year from a typical 1,200 sq ft roof.
Approximate annual value at municipal water rates.
Your roof and rainfall will differ; run your exact numbers in the rainwater calculator.
The right setup for Iowa’s climate
Iowa averages around 34 inches of rain a year, a moderate climate where a standard 50-gallon barrel with a diverter refills reliably between garden waterings. Most households here are well served by the classic starter setup.
Rain Wizard 50 + Diverter Kit, reviewed against our independent testing criteria. See all six models side by side.
Common questions
Is it illegal to collect rainwater in Iowa?
Do I need a permit for a rain barrel in Iowa?
Does Iowa offer incentives for rainwater harvesting?
Sources
- Rainplan, 50-State Rainwater Collection Guide (2026)
- State statutes and water agency guidance for Iowa
- NOAA National Centers for Environmental Information, annual precipitation normals
- US EPA WaterSense, Outdoor Water Use fact sheet
Educational content, not legal advice. Laws change; confirm current rules with your state water agency.