RoofRainYield

Dayton, MN rainwater: 26,237 gallons off a roof

Dayton, MN: gallons off the roof each year

26,237gallons a year

That is a 1,500 sq ft asphalt roof under Dayton, MN's normal 33.0 inches of rain, about 795 gallons for every inch that falls.

In Dayton, 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 Maple Grove 2.9 Ne station (4.2 mi away). Dayton, MN ranks 47th wettest of the 103 cities covered in Minnesota.

Month by month in Dayton

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan0.78620
Feb0.96763
Mar1.681,335
Apr3.122,480153
May4.253,37812
Jun4.633,680
Jul4.363,465
Aug4.413,505
Sep3.212,551142
Oct2.842,257188
Nov1.651,311
Dec1.12890

Jun is the wettest month (4.63 in, 3,680 gal off the roof); Jan the driest (0.78 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 Dayton

Best fit: one 55-gallon barrel, which delivers about 414 gallons to the garden in a normal year (83.4% of its need).

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

TankWater used (gal/yr)Spills over (gal/yr)
55 gal41425,013
110 gal41425,013
165 gal41425,013
275 gal41425,013
550 gal41425,013
1,000 gal41425,013
1,500 gal41425,013
2,500 gal41425,013
5,000 gal41425,013

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