Chillicothe, OH rainwater: 34,622 gallons off a roof
Rainwater from a roof in Chillicothe, OH
34,622gallons a year
That is a 1,500 sq ft asphalt roof under Chillicothe, OH's normal 43.6 inches of rain, about 795 gallons for every inch that falls.
In Chillicothe, 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 Waverly station (15.9 mi away). Chillicothe, OH ranks 37th wettest of the 176 cities covered in Ohio.
Month by month in Chillicothe
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.20 | 2,543 | |
| Feb | 3.13 | 2,488 | |
| Mar | 4.25 | 3,378 | |
| Apr | 4.10 | 3,259 | 31 |
| May | 4.43 | 3,521 | |
| Jun | 4.37 | 3,473 | |
| Jul | 4.20 | 3,338 | 19 |
| Aug | 3.49 | 2,774 | 107 |
| Sep | 2.95 | 2,345 | 175 |
| Oct | 3.15 | 2,504 | 150 |
| Nov | 2.90 | 2,305 | |
| Dec | 3.39 | 2,694 |
May is the wettest month (4.43 in, 3,521 gal off the roof); Nov the driest (2.90 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 Chillicothe?
Best fit: one 55-gallon barrel, which delivers about 390 gallons to the garden in a normal year (81.0% 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 Chillicothe's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 390 | 32,987 |
| 110 gal | 390 | 32,987 |
| 165 gal | 390 | 32,987 |
| 275 gal | 390 | 32,987 |
| 550 gal | 390 | 32,987 |
| 1,000 gal | 390 | 32,987 |
| 1,500 gal | 390 | 32,987 |
| 2,500 gal | 390 | 32,987 |
| 5,000 gal | 390 | 32,987 |
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