SnowLoadCheck

Pierce County, WA Roof Snow Load - 15 psf

What ASCE 7 says about snow load in Pierce County

Moderate
15 psf

That's Pierce County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. ASCE 7's low-slope-roof minimum (§7.3.4) raises the governing figure to 15 psf - higher than the 10.5 psf the ground-load formula alone would give, and the code says use the larger one.

Converted to something you can actually eyeball on a roof: about 33 in. of fresh powder, 12 in. once it settles and packs down, or just 3 in. if it's turned to ice. Modern-code homes carry a load like this without issue; an older addition, a carport, or any flat-roofed section is where it is worth checking first.

Pierce County at a glance

Where Pierce County's figure sits nationally

Out of 2,758 rated US counties, Pierce County sits at #1,307, the top 47% nationally - #4 of 10 within Washington. 16 psf is Washington's typical county figure - Pierce County comes in 1 psf under it.

Near 47.0514°N 122.1532°W, FIPS 53053: Pierce County counts 941,170 residents and a 15 psf map value, which the code's own factors turn into 15 psf.

How much it actually snows in Pierce County

Most winters bring Pierce County roughly 5.6 in. of snow - NOAA's normal at MCMILLIN RSVR, WA US, 7.6 mi off. (fresh vs. packed vs. ice explains why.)

Read this before you rely on it

Pierce County's number above is ASCE 7-22's default case, not a custom calculation: ordinary residential occupancy, heated, sited on ground that's neither fully sheltered nor fully exposed. Any one of those changing - pitch, exposure, heating, occupancy - moves the real figure.

Nothing here substitutes for an address-level number. Get one free, in about a minute, from the ASCE 7 Hazard Tool using your own coordinates rather than Pierce County's county-wide figure. See the methodology guide.