Buffalo, MN rainwater: 25,227 gallons off a roof
Rainwater from a roof in Buffalo, MN
25,227gallons a year
That is a 1,500 sq ft asphalt roof under Buffalo, MN's normal 31.7 inches of rain, about 795 gallons for every inch that falls.
In Buffalo, 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 Buffalo 2ne station (1.7 mi away). Buffalo, MN ranks 68th wettest of the 103 cities covered in Minnesota.
Month by month in Buffalo
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.69 | 548 | |
| Feb | 1.02 | 811 | |
| Mar | 1.43 | 1,137 | |
| Apr | 2.57 | 2,043 | 222 |
| May | 4.23 | 3,362 | 15 |
| Jun | 4.41 | 3,505 | |
| Jul | 4.33 | 3,442 | 2 |
| Aug | 4.50 | 3,577 | |
| Sep | 3.39 | 2,694 | 120 |
| Oct | 2.51 | 1,995 | 229 |
| Nov | 1.52 | 1,208 | |
| Dec | 1.14 | 906 |
Aug is the wettest month (4.50 in, 3,577 gal off the roof); Jan the driest (0.69 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 Buffalo
Best fit: one 55-gallon barrel, which delivers about 498 gallons to the garden in a normal year (84.6% 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 Buffalo's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 498 | 23,919 |
| 110 gal | 498 | 23,919 |
| 165 gal | 498 | 23,919 |
| 275 gal | 498 | 23,919 |
| 550 gal | 498 | 23,919 |
| 1,000 gal | 498 | 23,919 |
| 1,500 gal | 498 | 23,919 |
| 2,500 gal | 498 | 23,919 |
| 5,000 gal | 498 | 23,919 |
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