Lawton, OK rainwater: 27,166 gallons off a roof
How much rain a roof in Lawton, OK collects
27,166gallons a year
That is a 1,500 sq ft asphalt roof under Lawton, OK's normal 34.2 inches of rain, about 795 gallons for every inch that falls.
In Lawton, 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 Lawton station (2.1 mi away). Lawton, OK ranks 36th wettest of the 45 cities covered in Oklahoma.
Month by month in Lawton
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 1.21 | 962 | |
| Feb | 1.71 | 1,359 | |
| Mar | 2.42 | 1,923 | |
| Apr | 3.28 | 2,607 | 133 |
| May | 4.95 | 3,934 | |
| Jun | 4.22 | 3,354 | 16 |
| Jul | 2.85 | 2,265 | 187 |
| Aug | 3.49 | 2,774 | 107 |
| Sep | 3.12 | 2,480 | 153 |
| Oct | 2.93 | 2,329 | 177 |
| Nov | 2.06 | 1,637 | |
| Dec | 1.94 | 1,542 |
May is the wettest month (4.95 in, 3,934 gal off the roof); Jan the driest (1.21 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 Lawton?
Best fit: one 55-gallon barrel, which delivers about 662 gallons to the garden in a normal year (85.5% 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 Lawton's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 662 | 25,769 |
| 110 gal | 662 | 25,769 |
| 165 gal | 662 | 25,769 |
| 275 gal | 662 | 25,769 |
| 550 gal | 662 | 25,769 |
| 1,000 gal | 662 | 25,769 |
| 1,500 gal | 662 | 25,769 |
| 2,500 gal | 662 | 25,769 |
| 5,000 gal | 662 | 25,769 |
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