Stillwater, MN rainwater: 26,388 gallons off a roof
Stillwater, MN: gallons off the roof each year
26,388gallons a year
That is a 1,500 sq ft asphalt roof under Stillwater, MN's normal 33.2 inches of rain, about 795 gallons for every inch that falls.
In Stillwater, 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 Stillwater 2sw station (1.4 mi away). Stillwater, MN ranks 36th wettest of the 103 cities covered in Minnesota.
Month by month in Stillwater
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.85 | 676 | |
| Feb | 0.92 | 731 | |
| Mar | 1.62 | 1,288 | |
| Apr | 2.97 | 2,361 | 172 |
| May | 4.17 | 3,314 | 22 |
| Jun | 4.79 | 3,807 | |
| Jul | 4.38 | 3,481 | |
| Aug | 4.41 | 3,505 | |
| Sep | 3.32 | 2,639 | 128 |
| Oct | 2.74 | 2,178 | 201 |
| Nov | 1.82 | 1,447 | |
| Dec | 1.21 | 962 |
Jun is the wettest month (4.79 in, 3,807 gal off the roof); Jan the driest (0.85 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
What size rain barrel for Stillwater
Best fit: one 55-gallon barrel, which delivers about 413 gallons to the garden in a normal year (78.9% 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 Stillwater's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 413 | 24,984 |
| 110 gal | 413 | 24,984 |
| 165 gal | 413 | 24,984 |
| 275 gal | 413 | 24,984 |
| 550 gal | 413 | 24,984 |
| 1,000 gal | 413 | 24,984 |
| 1,500 gal | 413 | 24,984 |
| 2,500 gal | 413 | 24,984 |
| 5,000 gal | 413 | 24,984 |
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