What kind of septic system do I have?

Septic system types vary from neighbor to neighbor. Older systems tend to have concrete tanks and use gravity to distribute liquid so the soil can clean it. Newer systems typically use an electric pressure system to distribute the liquids at intervals. What type of system you have depends on how much space there is, your soil, and other factors. Here’s a rundown of the different septic-system options in Washington State:

Types of Septic Systems | Washington State Department of Health

And to find out what type of system you have, go to Kingcounty.gov/septicrecords. 

What kind of soil do I have?

Soil types on the island are all over the map, no pun intended. Houses a block away from each other can have very different amounts and types of soil. A septic designer can help you test your soil to determine the best system for your property.

For a general overview of the types of soils on the island, check out this Geology of the Rock map.

If you’d like to dig deeper, read this article about Vashon aquifers.