RoofRainYield

Port Angeles, WA rainwater: 21,094 gallons off a roof

How much rain a roof in Port Angeles, WA collects

21,094gallons a year

That is a 1,500 sq ft asphalt roof under Port Angeles, WA's normal 26.5 inches of rain, about 795 gallons for every inch that falls.

Port Angeles, WA has gaps between storms long enough to drain a single barrel. Around 165 gallons of storage catches most of what is worth catching.

Rainfall: NOAA 1991-2020 climate normals, the Port Angeles station (0.8 mi away). Port Angeles, WA ranks 71st wettest of the 91 cities covered in Washington.

Month by month in Port Angeles

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan3.813,028
Feb2.411,915
Mar2.361,876
Apr1.571,248347
May1.08858408
Jun1.08858408
Jul0.55437474
Aug0.67533459
Sep1.22970390
Oct3.162,512148
Nov4.393,489
Dec4.243,370

Nov is the wettest month (4.39 in, 3,489 gal off the roof); Jul the driest (0.55 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 Port Angeles?

Best fit: 3 linked 55-gallon barrels, which delivers about 2,173 gallons to the garden in a normal year (82.5% of its need).

Before you buy, link barrels with a short hose at the base so they fill and drain together, and check the overflow points away from the house.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal1,02019,069
110 gal1,78218,307
165 gal2,17317,916
275 gal2,38717,702
550 gal2,38717,702
1,000 gal2,38717,702
1,500 gal2,38717,702
2,500 gal2,38717,702
5,000 gal2,38717,702

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 Washington?

Collecting and storing rooftop rainwater for use on site needs no water right permit, provided the roof is part of a fixed above-ground structure whose primary purpose is not rain collection. Ecology may set local restrictions on new systems if they harm instream values or existing water rights. No state storage cap in the policy.

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