Robbinsdale, MN rainwater: 26,713 gallons off a roof
Rainwater from a roof in Robbinsdale, MN
26,713gallons a year
That is a 1,500 sq ft asphalt roof under Robbinsdale, MN's normal 33.6 inches of rain, about 795 gallons for every inch that falls.
In Robbinsdale, 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 Robbinsdale 0.6 Sse station (0.5 mi away). Robbinsdale, MN ranks 30th wettest of the 103 cities covered in Minnesota.
Month by month in Robbinsdale
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.89 | 707 | |
| Feb | 1.16 | 922 | |
| Mar | 1.77 | 1,407 | |
| Apr | 3.23 | 2,567 | 140 |
| May | 4.31 | 3,426 | 5 |
| Jun | 4.37 | 3,473 | |
| Jul | 4.39 | 3,489 | |
| Aug | 4.37 | 3,473 | |
| Sep | 3.26 | 2,591 | 136 |
| Oct | 2.89 | 2,297 | 182 |
| Nov | 1.68 | 1,335 | |
| Dec | 1.29 | 1,025 |
Jul is the wettest month (4.39 in, 3,489 gal off the roof); Jan the driest (0.89 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 Robbinsdale
Best fit: one 55-gallon barrel, which delivers about 366 gallons to the garden in a normal year (79.1% 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 Robbinsdale's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 366 | 25,342 |
| 110 gal | 366 | 25,342 |
| 165 gal | 366 | 25,342 |
| 275 gal | 366 | 25,342 |
| 550 gal | 366 | 25,342 |
| 1,000 gal | 366 | 25,342 |
| 1,500 gal | 366 | 25,342 |
| 2,500 gal | 366 | 25,342 |
| 5,000 gal | 366 | 25,342 |
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