Please help, thank you, my house is rented to someone else, and then the kitchen is under the sink

His failure to turn off the water pipes was the direct cause of this accident, the house is yours, and you are also responsible, depending on how you two talk. I think he's primarily responsible, and you should be held accountable. Because the house is yours.

Personal opinions are not necessarily true.

Yes, that's how I see it.

The responsibility is shared between both of you. The proportion of the burden depends on what you talk about, and the principle is that he has the main responsibility.

In the future, decorating the house, even if it is rented, water, electricity and waterproofing must not be sloppy.

If the tenant is responsible, you can go to the arbitration agency and request arbitration, but the water company will definitely come to you first to solve the problem, and you can ask the tenant for compensation. If there was a problem with the water pipe before, and the tenant did not respond and asked you to solve it, it was his business, and if you did not solve the problem when asked to solve it, you are also responsible.

The tenant is responsible, the landlord is also responsible, how to divide, I don't know, it's best to consult a specialized person.