Lake Elmo, MN rainwater: 26,729 gallons off a roof
Lake Elmo, MN: gallons off the roof each year
26,729gallons a year
That is a 1,500 sq ft asphalt roof under Lake Elmo, MN's normal 33.6 inches of rain, about 795 gallons for every inch that falls.
In Lake Elmo, 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 Oak Park Heights 2.4 W station (4.4 mi away). Lake Elmo, MN ranks 29th wettest of the 103 cities covered in Minnesota.
Month by month in Lake Elmo
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 1.01 | 803 | |
| Feb | 0.94 | 747 | |
| Mar | 1.70 | 1,351 | |
| Apr | 3.10 | 2,464 | 156 |
| May | 4.27 | 3,394 | 10 |
| Jun | 4.84 | 3,847 | |
| Jul | 4.41 | 3,505 | |
| Aug | 4.20 | 3,338 | 19 |
| Sep | 3.37 | 2,678 | 122 |
| Oct | 2.88 | 2,289 | 183 |
| Nov | 1.62 | 1,288 | |
| Dec | 1.29 | 1,025 |
Jun is the wettest month (4.84 in, 3,847 gal off the roof); Feb the driest (0.94 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 Lake Elmo
Best fit: one 55-gallon barrel, which delivers about 388 gallons to the garden in a normal year (79.2% 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 Lake Elmo's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 388 | 25,352 |
| 110 gal | 388 | 25,352 |
| 165 gal | 388 | 25,352 |
| 275 gal | 388 | 25,352 |
| 550 gal | 388 | 25,352 |
| 1,000 gal | 388 | 25,352 |
| 1,500 gal | 388 | 25,352 |
| 2,500 gal | 388 | 25,352 |
| 5,000 gal | 388 | 25,352 |
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