Chaska, MN rainwater: 26,682 gallons off a roof
How much rain a roof in Chaska, MN collects
26,682gallons a year
That is a 1,500 sq ft asphalt roof under Chaska, MN's normal 33.6 inches of rain, about 795 gallons for every inch that falls.
In Chaska, 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 Chaska 0.6 E station (0.6 mi away). Chaska, MN ranks 31st wettest of the 103 cities covered in Minnesota.
Month by month in Chaska
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.89 | 707 | |
| Feb | 0.86 | 684 | |
| Mar | 1.72 | 1,367 | |
| Apr | 3.07 | 2,440 | 160 |
| May | 4.12 | 3,275 | 29 |
| Jun | 5.54 | 4,403 | |
| Jul | 3.99 | 3,171 | 45 |
| Aug | 4.43 | 3,521 | |
| Sep | 3.27 | 2,599 | 135 |
| Oct | 2.72 | 2,162 | 203 |
| Nov | 1.74 | 1,383 | |
| Dec | 1.22 | 970 |
Jun is the wettest month (5.54 in, 4,403 gal off the roof); Feb the driest (0.86 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 Chaska?
Best fit: one 55-gallon barrel, which delivers about 458 gallons to the garden in a normal year (80.2% 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 Chaska's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 458 | 25,279 |
| 110 gal | 458 | 25,279 |
| 165 gal | 458 | 25,279 |
| 275 gal | 458 | 25,279 |
| 550 gal | 458 | 25,279 |
| 1,000 gal | 458 | 25,279 |
| 1,500 gal | 458 | 25,279 |
| 2,500 gal | 458 | 25,279 |
| 5,000 gal | 458 | 25,279 |
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