早速のお返事ありがとうございます。
RTOに相談した際の返事です。
A tenant is responsible for telling a landlord about problems with the plumbing. A landlord is responsible for fixing them.
Did you keep notes on when you told your landlord about the leaking shower? If you kept notes, or sent him a letter or an email, you may be able to show that you did what you were supposed to, and that the problems for the downstairs tenant could have been prevented.
If your landlord charges you for the repair (for example, if he takes the $450 from the security deposit), you may apply to the Residential Tenancy Branch for dispute resolution, seeking an order that you get this money back.・・・・・・