3,047 of the 3,075 lots in Auburn (99%) are zoned for houses inside an urban growth area. On those lots, Washington's HB 1337 requires the city or county to allow at least two accessory dwelling units (ADUs). Another 0 lots are outside the urban growth area, where Pierce County's own ADU rules decide.
3 of the 3,075 lots in Auburn (0%) have septic records on file with the Tacoma-Pierce County Health Department. 966 lots are inside a Pierce County sewer service area, and 0 are within 300 feet of a county sewer main.
Of the 3,075 lots in Auburn, 2 touch a mapped landslide hazard area, 0 an erosion hazard area, 3,075 a flood area and 69 an inventoried wetland, on Pierce County's maps.
From the Pierce County Assessor-Treasurer, the county's zoning, sewer, hazard and growth-area maps, and the Tacoma-Pierce County Health Department. Records as of October 2, 2026.
How these numbers are worked out · Guides