RoofRainYield

Reedley, CA rainwater: 15,546 gallons off a roof

Rainwater from a roof in Reedley, CA

15,546gallons a year

That is a 1,500 sq ft asphalt roof under Reedley, CA's normal 19.6 inches of rain, about 795 gallons for every inch that falls.

Reedley, CA's rain arrives in a wet season and stops, so storage is what matters. It takes a cistern of 2,500 gallons to carry spring rain into the dry months.

Rainfall: NOAA 1991-2020 climate normals, the Pine Flat Dam station (16.5 mi away). Reedley, CA ranks 94th wettest of the 376 cities covered in California.

Month by month in Reedley

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.903,100
Feb3.542,814
Mar3.442,734
Apr1.631,296339
May0.84668438
Jun0.29230506
Jul0.0324539
Aug0.000542
Sep0.13103526
Oct0.99787419
Nov1.431,137
Dec3.342,655

Jan is the wettest month (3.90 in, 3,100 gal off the roof); Aug the driest (0.00 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 Reedley?

Best fit: a 2,500-gallon cistern, which delivers about 3,203 gallons to the garden in a normal year (96.8% of its need).

Before you buy, ask about a rebate first: cistern-sized storage costs real money, and a buried or tall tank may need a permit. Place it where a full tank (about 8.3 lb a gallon) sits on firm, level ground.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal49514,414
110 gal90514,005
165 gal1,15913,751
275 gal1,40413,506
550 gal1,67913,231
1,000 gal2,12912,781
1,500 gal2,62912,281
2,500 gal3,20311,706
5,000 gal3,20311,706

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 California?

Legal. Use of rainwater collected from rooftops does not require a water right permit (Rainwater Capture Act of 2012, Water Code 10570 et seq.). The Act does not change existing water rights; local building/plumbing codes still apply to installed systems.

Checked against the current source on 2026-11-06. Source