Forest Park, OH rainwater: 35,186 gallons off a roof
Rainwater from a roof in Forest Park, OH
35,186gallons a year
That is a 1,500 sq ft asphalt roof under Forest Park, OH's normal 44.3 inches of rain, about 795 gallons for every inch that falls.
In Forest Park, 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 Cincinnati 8.9 Nw station (3.8 mi away). Forest Park, OH ranks 23rd wettest of the 176 cities covered in Ohio.
Month by month in Forest Park
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.27 | 2,599 | |
| Feb | 3.02 | 2,400 | |
| Mar | 3.91 | 3,108 | |
| Apr | 4.65 | 3,696 | |
| May | 4.88 | 3,879 | |
| Jun | 4.63 | 3,680 | |
| Jul | 3.90 | 3,100 | 56 |
| Aug | 3.05 | 2,424 | 162 |
| Sep | 3.18 | 2,527 | 146 |
| Oct | 3.19 | 2,535 | 145 |
| Nov | 3.17 | 2,520 | |
| Dec | 3.42 | 2,718 |
May is the wettest month (4.88 in, 3,879 gal off the roof); Feb the driest (3.02 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 Forest Park
Best fit: one 55-gallon barrel, which delivers about 415 gallons to the garden in a normal year (81.6% 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 Forest Park's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 415 | 33,572 |
| 110 gal | 415 | 33,572 |
| 165 gal | 415 | 33,572 |
| 275 gal | 415 | 33,572 |
| 550 gal | 415 | 33,572 |
| 1,000 gal | 415 | 33,572 |
| 1,500 gal | 415 | 33,572 |
| 2,500 gal | 415 | 33,572 |
| 5,000 gal | 415 | 33,572 |
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