Hot Water Question

Hello,

Recently the water heater in the house I rent in Washington, D.C. has gone bad. We get hot water for about 5-10 minutes, and then we have ice water. My landlord is claiming that we have to fix it if it falls under 250 dollars because within our lease it says we are responsible for repairs less than 250 dollars. I just want to make sure she is within her rights to make us pay to fix the water heater.

Thanks.