Marietta, OH rainwater: 35,218 gallons off a roof
Rainwater from a roof in Marietta, OH
35,218gallons a year
That is a 1,500 sq ft asphalt roof under Marietta, OH's normal 44.3 inches of rain, about 795 gallons for every inch that falls.
In Marietta, 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 Marietta Lock 1 station (0.9 mi away). Marietta, OH ranks 22nd wettest of the 176 cities covered in Ohio.
Month by month in Marietta
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.55 | 2,822 | |
| Feb | 3.12 | 2,480 | |
| Mar | 4.07 | 3,235 | |
| Apr | 3.86 | 3,068 | 61 |
| May | 4.05 | 3,219 | 37 |
| Jun | 4.78 | 3,799 | |
| Jul | 4.55 | 3,616 | |
| Aug | 3.65 | 2,901 | 87 |
| Sep | 3.29 | 2,615 | 132 |
| Oct | 3.04 | 2,416 | 163 |
| Nov | 2.89 | 2,297 | |
| Dec | 3.46 | 2,750 |
Jun is the wettest month (4.78 in, 3,799 gal off the roof); Nov the driest (2.89 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 Marietta?
Best fit: one 55-gallon barrel, which delivers about 380 gallons to the garden in a normal year (79.0% of its need).
Before you buy, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Marietta's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 380 | 33,577 |
| 110 gal | 380 | 33,577 |
| 165 gal | 380 | 33,577 |
| 275 gal | 380 | 33,577 |
| 550 gal | 380 | 33,577 |
| 1,000 gal | 380 | 33,577 |
| 1,500 gal | 380 | 33,577 |
| 2,500 gal | 380 | 33,577 |
| 5,000 gal | 380 | 33,577 |
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