Holly Hill, FL rainwater: 39,923 gallons off a roof
Holly Hill, FL: gallons off the roof each year
39,923gallons a year
That is a 1,500 sq ft asphalt roof under Holly Hill, FL's normal 50.2 inches of rain, about 795 gallons for every inch that falls.
In Holly Hill, 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 Ormond Beach 3.5 Se station (1.3 mi away). Holly Hill, FL ranks 162nd wettest of the 173 cities covered in Florida.
Month by month in Holly Hill
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 3.16 | 2,512 | |
| Feb | 2.81 | 2,233 | |
| Mar | 3.09 | 2,456 | |
| Apr | 2.45 | 1,947 | 237 |
| May | 3.94 | 3,132 | 51 |
| Jun | 5.90 | 4,689 | |
| Jul | 5.19 | 4,125 | |
| Aug | 6.79 | 5,397 | |
| Sep | 6.13 | 4,872 | |
| Oct | 5.12 | 4,069 | |
| Nov | 2.92 | 2,321 | |
| Dec | 2.73 | 2,170 |
Aug is the wettest month (6.79 in, 5,397 gal off the roof); Apr the driest (2.45 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 Holly Hill
Best fit: one 55-gallon barrel, which delivers about 239 gallons to the garden in a normal year (83.0% 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 Holly Hill's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 239 | 38,544 |
| 110 gal | 239 | 38,544 |
| 165 gal | 239 | 38,544 |
| 275 gal | 239 | 38,544 |
| 550 gal | 239 | 38,544 |
| 1,000 gal | 239 | 38,544 |
| 1,500 gal | 239 | 38,544 |
| 2,500 gal | 239 | 38,544 |
| 5,000 gal | 239 | 38,544 |
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