Brainerd, MN rainwater: 24,345 gallons off a roof
How much rain a roof in Brainerd, MN collects
24,345gallons a year
That is a 1,500 sq ft asphalt roof under Brainerd, MN's normal 30.6 inches of rain, about 795 gallons for every inch that falls.
In Brainerd, 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 Brainerd station (1.0 mi away). Brainerd, MN ranks 80th wettest of the 103 cities covered in Minnesota.
Month by month in Brainerd
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.80 | 636 | |
| Feb | 0.78 | 620 | |
| Mar | 1.47 | 1,168 | |
| Apr | 2.54 | 2,019 | 226 |
| May | 3.93 | 3,124 | 52 |
| Jun | 4.64 | 3,688 | |
| Jul | 4.37 | 3,473 | |
| Aug | 3.59 | 2,853 | 95 |
| Sep | 3.00 | 2,384 | 168 |
| Oct | 2.98 | 2,369 | 171 |
| Nov | 1.49 | 1,184 | |
| Dec | 1.04 | 827 |
Jun is the wettest month (4.64 in, 3,688 gal off the roof); Feb 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 Brainerd
Best fit: one 55-gallon barrel, which delivers about 568 gallons to the garden in a normal year (79.8% 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 Brainerd's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 568 | 22,832 |
| 110 gal | 568 | 22,832 |
| 165 gal | 568 | 22,832 |
| 275 gal | 568 | 22,832 |
| 550 gal | 568 | 22,832 |
| 1,000 gal | 568 | 22,832 |
| 1,500 gal | 568 | 22,832 |
| 2,500 gal | 568 | 22,832 |
| 5,000 gal | 568 | 22,832 |
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