Oldsmar, FL rainwater: 43,881 gallons off a roof
Rainwater from a roof in Oldsmar, FL
43,881gallons a year
That is a 1,500 sq ft asphalt roof under Oldsmar, FL's normal 55.2 inches of rain, about 795 gallons for every inch that falls.
In Oldsmar, 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 Dunedin 2.8 Ese station (5.8 mi away). Oldsmar, FL ranks 100th wettest of the 173 cities covered in Florida.
Month by month in Oldsmar
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.82 | 2,241 | |
| Feb | 2.57 | 2,043 | |
| Mar | 2.83 | 2,249 | |
| Apr | 2.83 | 2,249 | 190 |
| May | 2.11 | 1,677 | 279 |
| Jun | 7.77 | 6,176 | |
| Jul | 10.21 | 8,115 | |
| Aug | 8.80 | 6,994 | |
| Sep | 7.52 | 5,977 | |
| Oct | 3.09 | 2,456 | 157 |
| Nov | 1.79 | 1,423 | |
| Dec | 2.87 | 2,281 |
Jul is the wettest month (10.21 in, 8,115 gal off the roof); Nov the driest (1.79 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 Oldsmar
Best fit: one 55-gallon barrel, which delivers about 521 gallons to the garden in a normal year (83.2% 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 Oldsmar's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 521 | 42,145 |
| 110 gal | 521 | 42,145 |
| 165 gal | 521 | 42,145 |
| 275 gal | 521 | 42,145 |
| 550 gal | 521 | 42,145 |
| 1,000 gal | 521 | 42,145 |
| 1,500 gal | 521 | 42,145 |
| 2,500 gal | 521 | 42,145 |
| 5,000 gal | 521 | 42,145 |
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