Gainesville, GA rainwater: 41,632 gallons off a roof
Rainwater from a roof in Gainesville, GA
41,632gallons a year
That is a 1,500 sq ft asphalt roof under Gainesville, GA's normal 52.4 inches of rain, about 795 gallons for every inch that falls.
In Gainesville, 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 Gainesville Gilmer Ap station (1.3 mi away). Gainesville, GA ranks 57th wettest of the 101 cities covered in Georgia.
Month by month in Gainesville
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 4.95 | 3,934 | |
| Feb | 4.65 | 3,696 | |
| Mar | 4.78 | 3,799 | |
| Apr | 3.98 | 3,163 | 46 |
| May | 4.01 | 3,187 | 42 |
| Jun | 4.23 | 3,362 | 15 |
| Jul | 4.42 | 3,513 | |
| Aug | 4.73 | 3,759 | |
| Sep | 3.89 | 3,092 | 57 |
| Oct | 3.85 | 3,060 | 62 |
| Nov | 4.18 | 3,322 | |
| Dec | 4.71 | 3,744 |
Jan is the wettest month (4.95 in, 3,934 gal off the roof); Oct the driest (3.85 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 Gainesville
Best fit: one 55-gallon barrel, which delivers about 180 gallons to the garden in a normal year (80.7% 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 Gainesville's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 180 | 40,237 |
| 110 gal | 180 | 40,237 |
| 165 gal | 180 | 40,237 |
| 275 gal | 180 | 40,237 |
| 550 gal | 180 | 40,237 |
| 1,000 gal | 180 | 40,237 |
| 1,500 gal | 180 | 40,237 |
| 2,500 gal | 180 | 40,237 |
| 5,000 gal | 180 | 40,237 |
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