Jacksonville, FL rainwater: 42,204 gallons off a roof
Jacksonville, FL: gallons off the roof each year
42,204gallons a year
That is a 1,500 sq ft asphalt roof under Jacksonville, FL's normal 53.1 inches of rain, about 795 gallons for every inch that falls.
In Jacksonville, FL 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 Jacksonville 4.2 Ese station (4.5 mi away). Jacksonville, FL ranks 130th wettest of the 173 cities covered in Florida.
Month by month in Jacksonville
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.28 | 2,607 | |
| Feb | 2.72 | 2,162 | |
| Mar | 3.21 | 2,551 | |
| Apr | 2.70 | 2,146 | 206 |
| May | 3.76 | 2,988 | 74 |
| Jun | 6.62 | 5,262 | |
| Jul | 5.86 | 4,658 | |
| Aug | 7.03 | 5,587 | |
| Sep | 7.84 | 6,231 | |
| Oct | 4.72 | 3,751 | |
| Nov | 2.35 | 1,868 | |
| Dec | 3.01 | 2,392 |
Sep is the wettest month (7.84 in, 6,231 gal off the roof); Nov the driest (2.35 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 Jacksonville
Best fit: one 55-gallon barrel, which delivers about 240 gallons to the garden in a normal year (85.9% 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 Jacksonville's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 240 | 40,824 |
| 110 gal | 240 | 40,824 |
| 165 gal | 240 | 40,824 |
| 275 gal | 240 | 40,824 |
| 550 gal | 240 | 40,824 |
| 1,000 gal | 240 | 40,824 |
| 1,500 gal | 240 | 40,824 |
| 2,500 gal | 240 | 40,824 |
| 5,000 gal | 240 | 40,824 |
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 Florida?
Legal. Florida approves onsite non-potable use of rainwater for landscape irrigation, vehicle washing, filling pools and fountains and, in some local jurisdictions, toilet/urinal flushing (Florida Plumbing Code). No state storage cap or registration for non-potable collection.
Checked against the current source on 2026-11-06. Source