Washington County, TN Roof Snow Load - 15 psf
What ASCE 7 says about snow load in Washington County
That's Washington County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. §7.3.4's low-slope minimum of 15 psf is what actually governs on a flat or low-pitch roof here - higher than the 10.5 psf the base ground-load formula gives.
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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Washington County at a glance
- Design roof snow load15 psf
- Ground snow load, ASCE 7 map15 psf
- National rank#1,334 of 2,758
- Tennessee rank#3 of 95
- Population139,642
- Annual snowfall, NOAA normal9.3 in.
- FIPS47179
Where Washington County's figure sits nationally
Out of 2,758 rated US counties, Washington County sits at #1,334, the top 48% nationally - #3 of 95 within Tennessee. Tennessee counties average 10.3 psf; Washington County runs 4.7 psf higher than that.
Near 36.2957°N 82.495°W, FIPS 47179: Washington County counts 139,642 residents and a 15 psf map value, which the code's own factors turn into 15 psf.
How much it actually snows in Washington County
Most winters bring Washington County roughly 9.3 in. of snow - NOAA's normal at ERWIN 1 W, TN US, 11.3 mi off. (fresh vs. packed vs. ice explains why.)
Read this before you rely on it
Washington 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 Washington County's county-wide figure. Details: the calculation guide.