There is no law in California which specifically provides that the landlord must reimburse you for an overly-high water bill as a result of the landlord's failure to repair a water leak. That being said, I think that any judge in California would require the landlord to reimburse you for the excess cost while there was a leak. The problem is, due to the fact that no law specifically governs this, your only remedy for collecting the reimbursement from your landlord is to demand it, and if they do not pay you, sue them in small claims court. There is no law in California under which you can lawfully deduct the excess water cost from your rent. Had you followed the proper notice procedures, you could have elected to hire someone yourself to perform the repairs, then deduct the cost of the repair from your rent, but that law only extends to repairs and not reimbursement for utilities. Make the demand in writing, and if the landlord does not reimburse you, your only options are to either sue the landlord in Small Claims Court (which will likely put you in a very bad position with the landlord), or wait until the end of your tenancy, keeping track of the expense, and demand reimbursement. Waiting, however, has its own risks as the statute of limitations on your claim against the landlord may expire. Your in a situation where you are kind of "damned if you do, damned if you don't." Good luck.
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