Calhoun, GA rainwater: 41,672 gallons off a roof
Calhoun, GA: gallons off the roof each year
41,672gallons a year
That is a 1,500 sq ft asphalt roof under Calhoun, GA's normal 52.4 inches of rain, about 795 gallons for every inch that falls.
In Calhoun, GA 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 Resaca station (6.5 mi away). Calhoun, GA ranks 56th wettest of the 101 cities covered in Georgia.
Month by month in Calhoun
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 5.20 | 4,133 | |
| Feb | 5.32 | 4,228 | |
| Mar | 5.10 | 4,054 | |
| Apr | 4.50 | 3,577 | |
| May | 3.78 | 3,004 | 71 |
| Jun | 3.65 | 2,901 | 87 |
| Jul | 3.84 | 3,052 | 64 |
| Aug | 4.15 | 3,298 | 25 |
| Sep | 4.15 | 3,298 | 25 |
| Oct | 3.60 | 2,861 | 94 |
| Nov | 4.10 | 3,259 | |
| Dec | 5.04 | 4,006 |
Feb is the wettest month (5.32 in, 4,228 gal off the roof); Oct the driest (3.60 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 Calhoun
Best fit: one 55-gallon barrel, which delivers about 298 gallons to the garden in a normal year (81.6% 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 Calhoun's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 298 | 40,204 |
| 110 gal | 298 | 40,204 |
| 165 gal | 298 | 40,204 |
| 275 gal | 298 | 40,204 |
| 550 gal | 298 | 40,204 |
| 1,000 gal | 298 | 40,204 |
| 1,500 gal | 298 | 40,204 |
| 2,500 gal | 298 | 40,204 |
| 5,000 gal | 298 | 40,204 |
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 Georgia?
Legal. Outdoor irrigation use is unrestricted; indoor non-potable systems must follow Appendix I 'Rainwater Recycling Systems' of the Georgia amendments to the state plumbing code. No state storage cap; potable use depends on local rules.
Checked against the current source on 2026-11-06. Source