Austin, MN rainwater: 28,788 gallons off a roof

Austin, MN: gallons off the roof each year

In Austin, MN a single barrel does most of the work. Storms come often enough that a small tank refills before it runs dry, and a bigger one would mostly sit full.

Rainfall: NOAA 1991-2020 climate normals, the Austin Waste Wtp Facility station (1.3 mi away). Austin, MN ranks 3rd wettest of the 103 cities covered in Minnesota.

Month by month in Austin

Jun is the wettest month (5.07 in, 4,030 gal off the roof); Feb the driest (1.10 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

Which tank size is worth it in Austin

Best fit: one 55-gallon barrel, which delivers about 347 gallons to the garden in a normal year (81.1% of its need).

Before you buy, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Austin's roof water will pass straight through it.

Simulated storm by storm through a normal year using the station's count of days with 0.1 in or more of rain each month.

Is rainwater collection legal in Minnesota?

No statewide rainwater harvesting regulations; check county for local incentives

From the 2015 (Pacific Northwest National Laboratory report 24347); not yet re-checked against current law, so check with your state water agency before building anything large. Source