Douglas, GA rainwater: 39,883 gallons off a roof
How much rain a roof in Douglas, GA collects
39,883gallons a year
That is a 1,500 sq ft asphalt roof under Douglas, GA's normal 50.2 inches of rain, about 795 gallons for every inch that falls.
In Douglas, 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 Douglas 2.5 Wsw station (2.4 mi away). Douglas, GA ranks 84th wettest of the 101 cities covered in Georgia.
Month by month in Douglas
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 4.33 | 3,442 | |
| Feb | 3.79 | 3,012 | |
| Mar | 4.46 | 3,545 | |
| Apr | 4.38 | 3,481 | |
| May | 3.04 | 2,416 | 163 |
| Jun | 5.42 | 4,308 | |
| Jul | 5.26 | 4,181 | |
| Aug | 5.48 | 4,356 | |
| Sep | 4.08 | 3,243 | 34 |
| Oct | 2.91 | 2,313 | 180 |
| Nov | 2.84 | 2,257 | |
| Dec | 4.19 | 3,330 |
Aug is the wettest month (5.48 in, 4,356 gal off the roof); Nov the driest (2.84 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
Which tank size is worth it in Douglas
Best fit: one 55-gallon barrel, which delivers about 320 gallons to the garden in a normal year (85.0% 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 Douglas's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 320 | 38,468 |
| 110 gal | 320 | 38,468 |
| 165 gal | 320 | 38,468 |
| 275 gal | 320 | 38,468 |
| 550 gal | 320 | 38,468 |
| 1,000 gal | 320 | 38,468 |
| 1,500 gal | 320 | 38,468 |
| 2,500 gal | 320 | 38,468 |
| 5,000 gal | 320 | 38,468 |
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