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.
County sewer maps do not show sewers run by cities, so a lot inside a city may be on sewer even when no county main is nearby.
Septic records include permits, designs and inspections; older ones are on microfilm and are found by parcel number.
Questions
Is Anderson Island on septic or sewer?
Both. 773 lots have septic records on file, and 3,789 are inside a county sewer service area. It varies lot by lot.
How do I find out if a house is on septic?
Search its address on Colvos Parcel: the report lists any septic records for the lot, the nearest county sewer main and the sewer service area, with links to the originals.
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.