Monroe, OH rainwater: 33,422 gallons off a roof
Rainwater from a roof in Monroe, OH
33,422gallons a year
That is a 1,500 sq ft asphalt roof under Monroe, OH's normal 42.1 inches of rain, about 795 gallons for every inch that falls.
In Monroe, OH 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 Middletown station (5.3 mi away). Monroe, OH ranks 88th wettest of the 176 cities covered in Ohio.
Month by month in Monroe
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.16 | 2,512 | |
| Feb | 2.44 | 1,939 | |
| Mar | 3.69 | 2,933 | |
| Apr | 4.42 | 3,513 | |
| May | 4.34 | 3,449 | 1 |
| Jun | 4.46 | 3,545 | |
| Jul | 3.65 | 2,901 | 87 |
| Aug | 3.42 | 2,718 | 116 |
| Sep | 2.93 | 2,329 | 177 |
| Oct | 3.14 | 2,496 | 151 |
| Nov | 3.01 | 2,392 | |
| Dec | 3.39 | 2,694 |
Jun is the wettest month (4.46 in, 3,545 gal off the roof); Feb the driest (2.44 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 Monroe?
Best fit: one 55-gallon barrel, which delivers about 446 gallons to the garden in a normal year (83.8% 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 Monroe's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 446 | 31,821 |
| 110 gal | 446 | 31,821 |
| 165 gal | 446 | 31,821 |
| 275 gal | 446 | 31,821 |
| 550 gal | 446 | 31,821 |
| 1,000 gal | 446 | 31,821 |
| 1,500 gal | 446 | 31,821 |
| 2,500 gal | 446 | 31,821 |
| 5,000 gal | 446 | 31,821 |
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 Ohio?
Legal. Ohio regulates rainwater cisterns used as a drinking-water source as private water systems (OAC chapter 3701-28): local health department permit, continuous disinfection and filtration. No state rule restricting non-potable collection or storage size.
Checked against the current source on 2026-11-06. Source