Pass on cloged drain bill to tenants?

[Mark Forest]

The tenants called me and said the laundry room drain was backing up. We called a plumber/drain cleaner company because we like to get on these things immediately, and I will not be available for a while. The plumber cleaned the clog and said he found stringy threads like on a mop clogging the pipe. The tenants have been there for over a year, so obviously they have been careless by allowing inappropriate things down the drain against the terms of the lease.

Would any of you pass the $250.00 bill on to them or wait till the next time after sending them a letter about proper disposal using drains?