Nanny Pay in Snohomish?

2-Step

I have two kids and one on the way and I'm trying to figure out a reasonable hourly rate for a part time nanny over the summer. I work from home, so I will be here while the nanny is here and plan to pop out of my office to nurse the baby. My kids will be 7, 4.5 and 4 months when the nanny starts. So, two potty trained and fairly easygoing kids and one newborn. We live on acreage far from the road with a lot of safe play areas outside, so I would expect she would stay here and play all day and not be driving them anywhere. Basic tasks would be just entertainment and meal prep and maybe some light cleanup - like dishes after lunch. I was thinking $17-$20 an hour, but that is kind of a shot in the dark. The 7 year old will not always be here, as he will be doing some summer camps. What do you pay your snohomish county nanny?