squareeyes
I have firsthand experience!
According to an entomologist I spoke with in Puyallup about five years ago, WS is the northernmost area that has subterranean termites (let’s call them ST’s). They apparently have no interest in any areas east of here. ST’s need food and moisture, so if you have areas of standing water around your house try to fix that. Also remove any wood that may sit close to your house.
In my case, I discovered ST’s when they ate through a bit of caulk at the doorway of my mudroom. Mudroom has a cinderblock foundation (bad!), and the ST’s came up through the holes in the cinderblock and ate most of the mudsill and partway up the vertical supports. A handy friend removed the drywall inside and a few rows of siding outside to effect repairs and we tried to fill in as many cinderblock holes with quikcrete that we could access.
Cascade Pest Control was the only company I found in Seattle that deals with ST’s. He had to dig a shallow trench around the affected area, mix up several gallons of Termidor, and fill the trench with it. Termidor doesn’t repel ST’s, they go through the treated soil, and take it back to the nest where it kills everyone. It continues to work for five years. Next summer will be five years for me so I plan to have Cascade back for another treatment, just to be safe. It’s not cheap – cost around $400 just to treat around the mudroom, would be $1200-$1500 to treat around my 800 square foot house. If I remember correctly, Cascade will guarantee for five years if you treat around the entire structure, in my case I only did the one room so no guarantee.
I could go on for an hour about ST’s. I find them both horrifying ($$$) and fascinating.
If the inspector you used at time of purchase didn’t notice any damage to the mudsill in the crawlspace perhaps this is an early discovery. I’ll keep my fingers crossed for you.