0 of the 3,790 lots in Anderson Island (0%) 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 3,677 lots are outside the urban growth area, where Pierce County's own ADU rules decide.
773 of the 3,790 lots in Anderson Island (20%) have septic records on file with the Tacoma-Pierce County Health Department. 3,789 lots are inside a Pierce County sewer service area, and 0 are within 300 feet of a county sewer main.
Vacant land in Anderson Island sold for a median of $57,845 per acre across 180 sales since October 1, 2023. Homes sold for a median of $427,000 across 108 sales. 176 new homes were permitted since October 1, 2021.
Of the 3,790 lots in Anderson Island, 1,799 touch a mapped landslide hazard area, 815 an erosion hazard area, 698 a flood area and 502 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