RoofRainYield

Everett, WA rainwater: 31,991 gallons off a roof

How much rain a roof in Everett, WA collects

31,991gallons a year

That is a 1,500 sq ft asphalt roof under Everett, WA's normal 40.3 inches of rain, about 795 gallons for every inch that falls.

Everett, 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 Everett station (0.7 mi away). Everett, WA ranks 52nd wettest of the 91 cities covered in Washington.

Month by month in Everett

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan5.044,006
Feb3.702,941
Mar4.113,267
Apr3.402,702118
May2.702,146206
Jun2.301,828256
Jul1.04827413
Aug1.15914399
Sep2.341,860251
Oct3.702,94181
Nov5.824,626
Dec4.953,934

Nov is the wettest month (5.82 in, 4,626 gal off the roof); Jul the driest (1.04 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 Everett

Best fit: 3 linked 55-gallon barrels, which delivers about 1,440 gallons to the garden in a normal year (83.6% of its need).

If you set one up, 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 gal1,01629,565
110 gal1,32529,256
165 gal1,44029,141
275 gal1,47429,106
550 gal1,47429,106
1,000 gal1,47429,106
1,500 gal1,47429,106
2,500 gal1,47429,106
5,000 gal1,47429,106

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