Salem, OH rainwater: 33,143 gallons off a roof
Rainwater from a roof in Salem, OH
33,143gallons a year
That is a 1,500 sq ft asphalt roof under Salem, OH's normal 41.7 inches of rain, about 795 gallons for every inch that falls.
In Salem, 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 Salem 4.5 Ne station (4.3 mi away). Salem, OH ranks 97th wettest of the 176 cities covered in Ohio.
Month by month in Salem
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.01 | 2,392 | |
| Feb | 2.39 | 1,900 | |
| Mar | 3.10 | 2,464 | |
| Apr | 3.80 | 3,020 | 69 |
| May | 4.06 | 3,227 | 36 |
| Jun | 4.36 | 3,465 | |
| Jul | 4.35 | 3,457 | |
| Aug | 3.53 | 2,806 | 102 |
| Sep | 3.85 | 3,060 | 62 |
| Oct | 3.26 | 2,591 | 136 |
| Nov | 3.01 | 2,392 | |
| Dec | 2.98 | 2,369 |
Jun is the wettest month (4.36 in, 3,465 gal off the roof); Feb the driest (2.39 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 Salem?
Best fit: one 55-gallon barrel, which delivers about 301 gallons to the garden in a normal year (74.3% 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 Salem's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 301 | 31,447 |
| 110 gal | 301 | 31,447 |
| 165 gal | 301 | 31,447 |
| 275 gal | 301 | 31,447 |
| 550 gal | 301 | 31,447 |
| 1,000 gal | 301 | 31,447 |
| 1,500 gal | 301 | 31,447 |
| 2,500 gal | 301 | 31,447 |
| 5,000 gal | 301 | 31,447 |
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