Who is responsible for water bills

[Moncy Samuel]

I bought a duplex last December and Today I got a surprise mail in my mailbox. One of the tenant in a duplex send me a water bill for $1000. The water bill is in his name however last month there was a water leak and the water company is charging him for the usage fee. I send my contractor and fixed the water leak as soon as i came to know about it. Now the question is, who is responsible in this situation and what are the next steps. Water line is in name of tenant and he pays bills every month.