Marco Island, FL rainwater: 42,363 gallons off a roof
How much rain a roof in Marco Island, FL collects
42,363gallons a year
That is a 1,500 sq ft asphalt roof under Marco Island, FL's normal 53.3 inches of rain, about 795 gallons for every inch that falls.
In Marco Island, 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 Marco Is station (1.3 mi away). Marco Island, FL ranks 128th wettest of the 173 cities covered in Florida.
Month by month in Marco Island
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.50 | 1,987 | |
| Feb | 1.91 | 1,518 | |
| Mar | 2.05 | 1,629 | |
| Apr | 2.48 | 1,971 | 233 |
| May | 3.38 | 2,686 | 121 |
| Jun | 8.36 | 6,645 | |
| Jul | 6.60 | 5,246 | |
| Aug | 9.16 | 7,280 | |
| Sep | 9.92 | 7,884 | |
| Oct | 3.21 | 2,551 | 142 |
| Nov | 2.02 | 1,606 | |
| Dec | 1.71 | 1,359 |
Sep is the wettest month (9.92 in, 7,884 gal off the roof); Dec the driest (1.71 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 Marco Island?
Best fit: one 55-gallon barrel, which delivers about 397 gallons to the garden in a normal year (80.0% 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 Marco Island's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 397 | 40,856 |
| 110 gal | 427 | 40,827 |
| 165 gal | 427 | 40,827 |
| 275 gal | 427 | 40,827 |
| 550 gal | 427 | 40,827 |
| 1,000 gal | 427 | 40,827 |
| 1,500 gal | 427 | 40,827 |
| 2,500 gal | 427 | 40,827 |
| 5,000 gal | 427 | 40,827 |
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