Brunswick, GA rainwater: 39,971 gallons off a roof
Rainwater from a roof in Brunswick, GA
39,971gallons a year
That is a 1,500 sq ft asphalt roof under Brunswick, GA's normal 50.3 inches of rain, about 795 gallons for every inch that falls.
In Brunswick, 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 Brunswick station (3.0 mi away). Brunswick, GA ranks 83rd wettest of the 101 cities covered in Georgia.
Month by month in Brunswick
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.54 | 2,814 | |
| Feb | 3.06 | 2,432 | |
| Mar | 3.80 | 3,020 | |
| Apr | 3.07 | 2,440 | 160 |
| May | 3.04 | 2,416 | 163 |
| Jun | 6.35 | 5,047 | |
| Jul | 4.94 | 3,926 | |
| Aug | 6.95 | 5,524 | |
| Sep | 6.26 | 4,975 | |
| Oct | 4.60 | 3,656 | |
| Nov | 2.03 | 1,613 | |
| Dec | 2.65 | 2,106 |
Aug is the wettest month (6.95 in, 5,524 gal off the roof); Nov the driest (2.03 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 Brunswick?
Best fit: one 55-gallon barrel, which delivers about 275 gallons to the garden in a normal year (85.2% 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 Brunswick's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 275 | 38,616 |
| 110 gal | 275 | 38,616 |
| 165 gal | 275 | 38,616 |
| 275 gal | 275 | 38,616 |
| 550 gal | 275 | 38,616 |
| 1,000 gal | 275 | 38,616 |
| 1,500 gal | 275 | 38,616 |
| 2,500 gal | 275 | 38,616 |
| 5,000 gal | 275 | 38,616 |
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