Leave the valve alone for now. The problem is in the
washing machine. There's a solenoid assembly that is
supposed to stay closed till it gets the voltage to open.
Go to your local library and get a book on appliance
repair that includes washing machines. The repair is
easy, the valve solenoid assembly is not very expensive.
Don't need to turn off the water heater unless you're
going to be running water out without it being replaced.
And you probably need to be calling the "water intake
valve" the "supply valve" instead.
Not still living in the apartment building, Catherine?

"chemqueries" wrote in message
oups.com...
Hello. My washing machine won't stop filling with water. The previous
residents of this house left the water faucets open all the time, and I
believe the valve may be broken (of course, there may be another
problem, but this is my first thought). I'd like to replace the valve
and see whether that helps. Before beginning this project, I will turn
off the water at the main shut off valve for the whole house. Please
tell me whether I need to turn off the water heater. It is a gas
powered water heater. I asked several people at the hardware store, and
they said that I do not need to turn off the water heater, but I'd like
to hear your thoughts. Also, if you have any other tips on this
project, please let me know. Thanks.