RoofRainYield

California City, CA rainwater: 4,578 gallons off a roof

California City, CA: gallons off the roof each year

4,578gallons a year

That is a 1,500 sq ft asphalt roof under California City, CA's normal 5.8 inches of rain, about 795 gallons for every inch that falls.

California City, CA's rain arrives in a wet season and stops, so storage is what matters. It takes a cistern of 5,000 gallons to carry spring rain into the dry months.

Rainfall: NOAA 1991-2020 climate normals, the Mojave station (17.9 mi away). California City, CA ranks 359th wettest of the 376 cities covered in California.

Month by month in California City

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.08858
Feb1.491,184
Mar0.80636
Apr0.21167516
May0.13103526
Jun0.0324539
Jul0.18143520
Aug0.17135521
Sep0.1079530
Oct0.42334490
Nov0.34270
Dec0.81644

Feb is the wettest month (1.49 in, 1,184 gal off the roof); Jun the driest (0.03 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

What size rain barrel for California City

Best fit: a 5,000-gallon cistern, which delivers about 3,609 gallons to the garden in a normal year (99.1% of its need).

If you buy one, 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 gal1653,763
110 gal3303,598
165 gal4823,446
275 gal6643,264
550 gal9392,989
1,000 gal1,3892,539
1,500 gal1,8892,039
2,500 gal2,8891,039
5,000 gal3,6090

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