Otsego, MN rainwater: 26,141 gallons off a roof
Rainwater from a roof in Otsego, MN
26,141gallons a year
That is a 1,500 sq ft asphalt roof under Otsego, MN's normal 32.9 inches of rain, about 795 gallons for every inch that falls.
In Otsego, 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 Elk Rvr station (3.3 mi away). Otsego, MN ranks 54th wettest of the 103 cities covered in Minnesota.
Month by month in Otsego
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.80 | 636 | |
| Feb | 0.83 | 660 | |
| Mar | 1.67 | 1,327 | |
| Apr | 3.04 | 2,416 | 163 |
| May | 4.20 | 3,338 | 19 |
| Jun | 4.45 | 3,537 | |
| Jul | 4.49 | 3,569 | |
| Aug | 4.03 | 3,203 | 40 |
| Sep | 3.61 | 2,869 | 92 |
| Oct | 2.96 | 2,353 | 173 |
| Nov | 1.71 | 1,359 | |
| Dec | 1.10 | 874 |
Jul is the wettest month (4.49 in, 3,569 gal off the roof); Jan the driest (0.80 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
Barrel or cistern in Otsego?
Best fit: one 55-gallon barrel, which delivers about 406 gallons to the garden in a normal year (83.3% 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 Otsego's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 406 | 24,925 |
| 110 gal | 406 | 24,925 |
| 165 gal | 406 | 24,925 |
| 275 gal | 406 | 24,925 |
| 550 gal | 406 | 24,925 |
| 1,000 gal | 406 | 24,925 |
| 1,500 gal | 406 | 24,925 |
| 2,500 gal | 406 | 24,925 |
| 5,000 gal | 406 | 24,925 |
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