McDonough, GA rainwater: 40,654 gallons off a roof
McDonough, GA: gallons off the roof each year
40,654gallons a year
That is a 1,500 sq ft asphalt roof under McDonough, GA's normal 51.2 inches of rain, about 795 gallons for every inch that falls.
In McDonough, 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 Mcdonough 5 Ene station (7.1 mi away). McDonough, GA ranks 70th wettest of the 101 cities covered in Georgia.
Month by month in McDonough
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 5.30 | 4,212 | |
| Feb | 4.47 | 3,553 | |
| Mar | 5.44 | 4,324 | |
| Apr | 3.82 | 3,036 | 66 |
| May | 3.31 | 2,631 | 130 |
| Jun | 4.32 | 3,434 | 4 |
| Jul | 4.43 | 3,521 | |
| Aug | 4.56 | 3,624 | |
| Sep | 3.73 | 2,965 | 77 |
| Oct | 3.45 | 2,742 | 112 |
| Nov | 3.65 | 2,901 | |
| Dec | 4.67 | 3,712 |
Mar is the wettest month (5.44 in, 4,324 gal off the roof); May the driest (3.31 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 McDonough
Best fit: one 55-gallon barrel, which delivers about 319 gallons to the garden in a normal year (82.0% 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 McDonough's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 319 | 39,180 |
| 110 gal | 319 | 39,180 |
| 165 gal | 319 | 39,180 |
| 275 gal | 319 | 39,180 |
| 550 gal | 319 | 39,180 |
| 1,000 gal | 319 | 39,180 |
| 1,500 gal | 319 | 39,180 |
| 2,500 gal | 319 | 39,180 |
| 5,000 gal | 319 | 39,180 |
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