Miami, OK rainwater: 36,561 gallons off a roof
Miami, OK: gallons off the roof each year
36,561gallons a year
That is a 1,500 sq ft asphalt roof under Miami, OK's normal 46.0 inches of rain, about 795 gallons for every inch that falls.
In Miami, OK 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 Columbus station (20.0 mi away). Miami, OK ranks 4th wettest of the 45 cities covered in Oklahoma.
Month by month in Miami
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 1.67 | 1,327 | |
| Feb | 1.99 | 1,582 | |
| Mar | 3.41 | 2,710 | |
| Apr | 5.07 | 4,030 | |
| May | 7.10 | 5,643 | |
| Jun | 5.17 | 4,109 | |
| Jul | 4.15 | 3,298 | 25 |
| Aug | 3.81 | 3,028 | 67 |
| Sep | 4.45 | 3,537 | |
| Oct | 3.77 | 2,996 | 72 |
| Nov | 2.98 | 2,369 | |
| Dec | 2.43 | 1,931 |
May is the wettest month (7.10 in, 5,643 gal off the roof); Jan the driest (1.67 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 Miami
Best fit: one 55-gallon barrel, which delivers about 135 gallons to the garden in a normal year (82.0% of its need).
Before you buy, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Miami's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 135 | 35,391 |
| 110 gal | 135 | 35,391 |
| 165 gal | 135 | 35,391 |
| 275 gal | 135 | 35,391 |
| 550 gal | 135 | 35,391 |
| 1,000 gal | 135 | 35,391 |
| 1,500 gal | 135 | 35,391 |
| 2,500 gal | 135 | 35,391 |
| 5,000 gal | 135 | 35,391 |
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 Oklahoma?
Encouraged through state legislation: Water for 2060 Act
From the 2015 (Pacific Northwest National Laboratory report 24347); not yet re-checked against current law, so check with your state water agency before building anything large. Source