As a landlord, I would pay Indah Water bills, but the rental will raise it for another rm50.

Only way is state clearly in the contract, but sometimes people will ignore the contract especially on the final few months.
TNB you can avoid this by spending rm10 to include tenant's name and when shit happens, you no need to be held responsible for this.
As for water bill and IWK, that's something that put lanlord at risk.