Hopkins, MN rainwater: 25,974 gallons off a roof
How much rain a roof in Hopkins, MN collects
25,974gallons a year
That is a 1,500 sq ft asphalt roof under Hopkins, MN's normal 32.7 inches of rain, about 795 gallons for every inch that falls.
In Hopkins, 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 Golden Valley 0.8 Wsw station (4.4 mi away). Hopkins, MN ranks 60th wettest of the 103 cities covered in Minnesota.
Month by month in Hopkins
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.82 | 652 | |
| Feb | 0.86 | 684 | |
| Mar | 1.65 | 1,311 | |
| Apr | 3.00 | 2,384 | 168 |
| May | 4.32 | 3,434 | 4 |
| Jun | 4.60 | 3,656 | |
| Jul | 4.21 | 3,346 | 17 |
| Aug | 4.40 | 3,497 | |
| Sep | 3.01 | 2,392 | 167 |
| Oct | 2.91 | 2,313 | 180 |
| Nov | 1.69 | 1,343 | |
| Dec | 1.21 | 962 |
Jun is the wettest month (4.60 in, 3,656 gal off the roof); Jan the driest (0.82 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 Hopkins?
Best fit: one 55-gallon barrel, which delivers about 424 gallons to the garden in a normal year (79.1% 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 Hopkins's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 424 | 24,545 |
| 110 gal | 424 | 24,545 |
| 165 gal | 424 | 24,545 |
| 275 gal | 424 | 24,545 |
| 550 gal | 424 | 24,545 |
| 1,000 gal | 424 | 24,545 |
| 1,500 gal | 424 | 24,545 |
| 2,500 gal | 424 | 24,545 |
| 5,000 gal | 424 | 24,545 |
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