Detroit Lakes, MN rainwater: 23,407 gallons off a roof
Rainwater from a roof in Detroit Lakes, MN
23,407gallons a year
That is a 1,500 sq ft asphalt roof under Detroit Lakes, MN's normal 29.5 inches of rain, about 795 gallons for every inch that falls.
In Detroit Lakes, 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 Detroit Lakes 1 Nne station (2.1 mi away). Detroit Lakes, MN ranks 87th wettest of the 103 cities covered in Minnesota.
Month by month in Detroit Lakes
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.82 | 652 | |
| Feb | 0.66 | 525 | |
| Mar | 0.96 | 763 | |
| Apr | 2.03 | 1,613 | 289 |
| May | 3.73 | 2,965 | 77 |
| Jun | 4.90 | 3,895 | |
| Jul | 4.35 | 3,457 | |
| Aug | 3.26 | 2,591 | 136 |
| Sep | 3.55 | 2,822 | 100 |
| Oct | 2.84 | 2,257 | 188 |
| Nov | 1.37 | 1,089 | |
| Dec | 0.98 | 779 |
Jun is the wettest month (4.90 in, 3,895 gal off the roof); Feb the driest (0.66 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 Detroit Lakes?
Best fit: one 55-gallon barrel, which delivers about 618 gallons to the garden in a normal year (78.2% of its need).
If you buy one, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Detroit Lakes's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 618 | 21,889 |
| 110 gal | 646 | 21,861 |
| 165 gal | 646 | 21,861 |
| 275 gal | 646 | 21,861 |
| 550 gal | 646 | 21,861 |
| 1,000 gal | 646 | 21,861 |
| 1,500 gal | 646 | 21,861 |
| 2,500 gal | 646 | 21,861 |
| 5,000 gal | 646 | 21,861 |
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