Columbus, OH rainwater: 33,525 gallons off a roof
Columbus, OH: gallons off the roof each year
33,525gallons a year
That is a 1,500 sq ft asphalt roof under Columbus, OH's normal 42.2 inches of rain, about 795 gallons for every inch that falls.
In Columbus, 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 Grandview Heights 0.1 N station (2.9 mi away). Columbus, OH ranks 80th wettest of the 176 cities covered in Ohio.
Month by month in Columbus
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.95 | 2,345 | |
| Feb | 2.33 | 1,852 | |
| Mar | 3.37 | 2,678 | |
| Apr | 3.95 | 3,139 | 50 |
| May | 4.59 | 3,648 | |
| Jun | 4.56 | 3,624 | |
| Jul | 4.73 | 3,759 | |
| Aug | 3.67 | 2,917 | 85 |
| Sep | 3.11 | 2,472 | 155 |
| Oct | 2.84 | 2,257 | 188 |
| Nov | 2.99 | 2,376 | |
| Dec | 3.09 | 2,456 |
Jul is the wettest month (4.73 in, 3,759 gal off the roof); Feb the driest (2.33 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
Which tank size is worth it in Columbus
Best fit: one 55-gallon barrel, which delivers about 373 gallons to the garden in a normal year (78.1% 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 Columbus's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 373 | 31,877 |
| 110 gal | 373 | 31,877 |
| 165 gal | 373 | 31,877 |
| 275 gal | 373 | 31,877 |
| 550 gal | 373 | 31,877 |
| 1,000 gal | 373 | 31,877 |
| 1,500 gal | 373 | 31,877 |
| 2,500 gal | 373 | 31,877 |
| 5,000 gal | 373 | 31,877 |
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