Defiance, OH rainwater: 29,964 gallons off a roof
Defiance, OH: gallons off the roof each year
29,964gallons a year
That is a 1,500 sq ft asphalt roof under Defiance, OH's normal 37.7 inches of rain, about 795 gallons for every inch that falls.
In Defiance, 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 Defiance station (1.0 mi away). Defiance, OH ranks 155th wettest of the 176 cities covered in Ohio.
Month by month in Defiance
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.59 | 2,059 | |
| Feb | 2.17 | 1,725 | |
| Mar | 2.55 | 2,027 | |
| Apr | 3.67 | 2,917 | 85 |
| May | 4.26 | 3,386 | 11 |
| Jun | 3.63 | 2,885 | 90 |
| Jul | 3.66 | 2,909 | 86 |
| Aug | 3.50 | 2,782 | 106 |
| Sep | 3.25 | 2,583 | 137 |
| Oct | 2.87 | 2,281 | 185 |
| Nov | 3.00 | 2,384 | |
| Dec | 2.55 | 2,027 |
May is the wettest month (4.26 in, 3,386 gal off the roof); Feb the driest (2.17 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 Defiance
Best fit: one 55-gallon barrel, which delivers about 544 gallons to the garden in a normal year (77.8% 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 Defiance's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 544 | 28,206 |
| 110 gal | 544 | 28,206 |
| 165 gal | 544 | 28,206 |
| 275 gal | 544 | 28,206 |
| 550 gal | 544 | 28,206 |
| 1,000 gal | 544 | 28,206 |
| 1,500 gal | 544 | 28,206 |
| 2,500 gal | 544 | 28,206 |
| 5,000 gal | 544 | 28,206 |
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