Surprise lien letter from WA utilities on my recent duplex

[Carlos Enriquez]

I live in California and I purchased a duplex in WA State and closed on 7/24/2015.  I had a PM already contracted to take over the same day, which he did go over and talk to the two tenants.

Last week, on 9/16, 2015, I received a letter from the utilities that stated that in WA State, the owner is responsible for water/sewer/trash and that my tenants are delinquent, and it is a lienable offense!  I was very surprised, since I had not heard about this and my PM never mentioned it.  The utilities said that the PM never registered in July as my PM and that if he had, he would have received a duplicate bill and could have been on top of it, but that's a different story.  PM's need to register themselves as an owner's PM to be able to deal with utilities directly.

Since the trash is a fixed amount, I think that I will add it to the monthly rent once the leases expire.  It's only $20 a month, and a PM will get the duplicate bill, not a tenant.  Twenty dollars more on top of the rent amount won't seem exorbitant.

But water/sewer is where I'm trying to decide if to have tenants pay directly with a "tenant" bill, or if I should charge an average on top of the rent?  With the base fee, step1, step2, step3, along with sewer base and steps, the charges are always different and confusing, so it will be hard to get an average.  Most likely I'll have the PM monitor the duplicate bills to see that they are kept up with, and try to collect when not paid, because I don't want to get stuck paying them when the tenants ignore it.

Is it grounds for eviction when the lease stipulates that tenants are responsible for paying utilities?

What do you Washington State landlords do about this?