RoofRainYield

Parlier, CA rainwater: 9,403 gallons off a roof

How much rain a roof in Parlier, CA collects

9,403gallons a year

That is a 1,500 sq ft asphalt roof under Parlier, CA's normal 11.8 inches of rain, about 795 gallons for every inch that falls.

Parlier, 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 Fresno 5 Ne station (14.3 mi away). Parlier, CA ranks 297th wettest of the 376 cities covered in California.

Month by month in Parlier

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan2.271,804
Feb1.891,502
Mar2.241,780
Apr1.00795418
May0.55437474
Jun0.18143520
Jul0.0324539
Aug0.018541
Sep0.1187529
Oct0.56445473
Nov0.96763
Dec2.031,613

Jan is the wettest month (2.27 in, 1,804 gal off the roof); Aug the driest (0.01 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 Parlier

Best fit: a 2,500-gallon cistern, which delivers about 3,348 gallons to the garden in a normal year (95.9% 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 gal2758,505
110 gal5378,243
165 gal7578,023
275 gal1,0717,709
550 gal1,3987,383
1,000 gal1,8486,933
1,500 gal2,3486,433
2,500 gal3,3485,433
5,000 gal3,4345,346

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