Kennesaw, GA rainwater: 42,633 gallons off a roof
Rainwater from a roof in Kennesaw, GA
42,633gallons a year
That is a 1,500 sq ft asphalt roof under Kennesaw, GA's normal 53.6 inches of rain, about 795 gallons for every inch that falls.
In Kennesaw, 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 Kennesaw 5.6 Sw station (5.8 mi away). Kennesaw, GA ranks 32nd wettest of the 101 cities covered in Georgia.
Month by month in Kennesaw
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 4.69 | 3,728 | |
| Feb | 4.84 | 3,847 | |
| Mar | 5.37 | 4,268 | |
| Apr | 4.50 | 3,577 | |
| May | 3.99 | 3,171 | 45 |
| Jun | 4.16 | 3,306 | 24 |
| Jul | 5.06 | 4,022 | |
| Aug | 4.05 | 3,219 | 37 |
| Sep | 4.15 | 3,298 | 25 |
| Oct | 3.51 | 2,790 | 105 |
| Nov | 4.57 | 3,632 | |
| Dec | 4.75 | 3,775 |
Mar is the wettest month (5.37 in, 4,268 gal off the roof); Oct the driest (3.51 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 Kennesaw?
Best fit: one 55-gallon barrel, which delivers about 190 gallons to the garden in a normal year (80.6% 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 Kennesaw's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 190 | 41,169 |
| 110 gal | 190 | 41,169 |
| 165 gal | 190 | 41,169 |
| 275 gal | 190 | 41,169 |
| 550 gal | 190 | 41,169 |
| 1,000 gal | 190 | 41,169 |
| 1,500 gal | 190 | 41,169 |
| 2,500 gal | 190 | 41,169 |
| 5,000 gal | 190 | 41,169 |
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