Okmulgee, OK rainwater: 37,618 gallons off a roof
Rainwater from a roof in Okmulgee, OK
37,618gallons a year
That is a 1,500 sq ft asphalt roof under Okmulgee, OK's normal 47.3 inches of rain, about 795 gallons for every inch that falls.
In Okmulgee, 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 Dewar 2 Ne station (12.0 mi away). Okmulgee, OK ranks 3rd wettest of the 45 cities covered in Oklahoma.
Month by month in Okmulgee
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 2.21 | 1,757 | |
| Feb | 1.93 | 1,534 | |
| Mar | 3.53 | 2,806 | |
| Apr | 4.35 | 3,457 | |
| May | 6.79 | 5,397 | |
| Jun | 4.99 | 3,966 | |
| Jul | 3.93 | 3,124 | 52 |
| Aug | 4.29 | 3,410 | 7 |
| Sep | 4.90 | 3,895 | |
| Oct | 4.33 | 3,442 | 2 |
| Nov | 3.30 | 2,623 | |
| Dec | 2.78 | 2,210 |
May is the wettest month (6.79 in, 5,397 gal off the roof); Feb the driest (1.93 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 Okmulgee?
Best fit: one 55-gallon barrel, which delivers about 52 gallons to the garden in a normal year (83.4% 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 Okmulgee's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 52 | 36,591 |
| 110 gal | 52 | 36,591 |
| 165 gal | 52 | 36,591 |
| 275 gal | 52 | 36,591 |
| 550 gal | 52 | 36,591 |
| 1,000 gal | 52 | 36,591 |
| 1,500 gal | 52 | 36,591 |
| 2,500 gal | 52 | 36,591 |
| 5,000 gal | 52 | 36,591 |
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