My almost 30years old electrical hot water tank is leaking and flooding my basement. I turned off the power source to it and also turned the only knob/valve that l see off in hopes of stopping water flow to the tank but it is not working. How do l stop water flow into the tank to prevent flooding of my basement?
If the water valve does not stop the flow, then you have one of these conditions, with the most likely first;
1. The valve is defective
2. You have a single handle faucet in the house which needs to be repaired.
3. The water lines are connected to the heater backwards
Licensed residential and commercial plumber
If the valve going to the WH does not stop the flow (keep in mind that it will still potentially empty the tank, but the goal is to stop new water from getting into it), then the next step would be to turn off the water to the house. In the meantime, put a hose on the drain of the WH and open the T&P valve on the top of it (this is the safety valve that has a lever on it) to drain the tank through the hose. Hopefully, you have somewhere safe to let that drain to, otherwise, maybe run it into a bucket and dump it out in a safe location.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013
are you sure the water supply is not turning off and the water you are seeing is the water that is in the tank?
Just suggesting to look for the obvious first.