Montgomery, OH rainwater: 35,409 gallons off a roof
Rainwater from a roof in Montgomery, OH
35,409gallons a year
That is a 1,500 sq ft asphalt roof under Montgomery, OH's normal 44.6 inches of rain, about 795 gallons for every inch that falls.
In Montgomery, 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 Kings Mills station (8.5 mi away). Montgomery, OH ranks 19th wettest of the 176 cities covered in Ohio.
Month by month in Montgomery
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.35 | 2,663 | |
| Feb | 2.82 | 2,241 | |
| Mar | 3.85 | 3,060 | |
| Apr | 4.68 | 3,720 | |
| May | 4.94 | 3,926 | |
| Jun | 4.60 | 3,656 | |
| Jul | 3.84 | 3,052 | 64 |
| Aug | 3.72 | 2,957 | 79 |
| Sep | 3.00 | 2,384 | 168 |
| Oct | 3.23 | 2,567 | 140 |
| Nov | 3.07 | 2,440 | |
| Dec | 3.45 | 2,742 |
May is the wettest month (4.94 in, 3,926 gal off the roof); Feb the driest (2.82 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 Montgomery
Best fit: one 55-gallon barrel, which delivers about 370 gallons to the garden in a normal year (82.2% 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 Montgomery's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 370 | 33,794 |
| 110 gal | 370 | 33,794 |
| 165 gal | 370 | 33,794 |
| 275 gal | 370 | 33,794 |
| 550 gal | 370 | 33,794 |
| 1,000 gal | 370 | 33,794 |
| 1,500 gal | 370 | 33,794 |
| 2,500 gal | 370 | 33,794 |
| 5,000 gal | 370 | 33,794 |
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