Service / Emotional Support Dogs

[Levi Kruse]

Washington state, Cowlitz County

Hello, I am new (2 days) to the landlord scene and I have a duplex with inherited tenants. One tenant has 4 small (large rat size) dogs and claims that they are emotional support/ service dogs and that I can not legally charge pet rent. I am reading up on service dogs and I cant find reference to limits, can a tenant have as many service animals as they like without any recourse on my end (even though damage is more likely and insurance is more expensive for me)?

Sorry if this has been answered already I cant seem to find anything useful with my search terms :-(