Surprise Drainage Utility Bill

I received a surprise Drainage Utility Bill for ~$90. I have owned a duplex for 3 years and never paid a water bill as those are normally under the tenants name and responsibility. Can anyone tell me if this is a new fee being charged? Their office is not open till Monday and I am confused how I owe $90 all of the sudden when I have not had a bill like this for 3 years.