Writing sewage and sump pump care into lease: any suggestions?

[Athena Flint]

Newbie here trying to compile a lease for a house in PA. It's a country house so it has well water and a sump pump, and I want to make sure that it's clear in the lease that if the Tenants cause damage to the sewage system by disposing of improper things down the drain they will be covering the costs of fixing it! 

Is there anyone who would be willing to share how they have written that into a lease?