Savannah, GA rainwater: 41,322 gallons off a roof
Rainwater from a roof in Savannah, GA
41,322gallons a year
That is a 1,500 sq ft asphalt roof under Savannah, GA's normal 52.0 inches of rain, about 795 gallons for every inch that falls.
In Savannah, 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 Savannah 1.7 W station (2.3 mi away). Savannah, GA ranks 59th wettest of the 101 cities covered in Georgia.
Month by month in Savannah
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.55 | 2,822 | |
| Feb | 3.31 | 2,631 | |
| Mar | 3.88 | 3,084 | |
| Apr | 3.41 | 2,710 | 117 |
| May | 3.86 | 3,068 | 61 |
| Jun | 6.21 | 4,936 | |
| Jul | 5.96 | 4,737 | |
| Aug | 7.25 | 5,762 | |
| Sep | 4.72 | 3,751 | |
| Oct | 4.02 | 3,195 | 41 |
| Nov | 2.42 | 1,923 | |
| Dec | 3.40 | 2,702 |
Aug is the wettest month (7.25 in, 5,762 gal off the roof); Nov the driest (2.42 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 Savannah?
Best fit: one 55-gallon barrel, which delivers about 183 gallons to the garden in a normal year (83.4% 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 Savannah's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 183 | 40,029 |
| 110 gal | 183 | 40,029 |
| 165 gal | 183 | 40,029 |
| 275 gal | 183 | 40,029 |
| 550 gal | 183 | 40,029 |
| 1,000 gal | 183 | 40,029 |
| 1,500 gal | 183 | 40,029 |
| 2,500 gal | 183 | 40,029 |
| 5,000 gal | 183 | 40,029 |
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