Who is responsible for pest control on a rental in Washington?

[Jack B.]

My lease just says tenants are responsible for any condition they create regarding pests. New tenant moved in yesterday and claims there are ants by the back door. I was working on the house for a week and never saw ANY ants anywhere. I have liquid ant bait etc. that I can put down, but that generally made me wonder, who is responsible for pest control at the rental by law since my state provided lease doesn't adequately address this IMO...