Stillwater, OK rainwater: 28,645 gallons off a roof

Stillwater, OK: gallons off the roof each year

In Stillwater, 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 Stillwater 2 W station (1.3 mi away). Stillwater, OK ranks 32nd wettest of the 45 cities covered in Oklahoma.

Month by month in Stillwater

May is the wettest month (4.71 in, 3,744 gal off the roof); Jan the driest (1.32 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 Stillwater

Best fit: one 55-gallon barrel, which delivers about 489 gallons to the garden in a normal year (84.5% 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 Stillwater's roof water will pass straight through it.

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