I just bought my first new home. Right off the bat I experinced my first home owner repair. The gas was turned on, the hot water heater started up and tada the line to my toilet is a hot water line. I now know about the wax seal under the toilet and the effect of heat on porcelain. I have replaced the old cracked toilet with a new one and am very proud of myself for taking on this task. Now I am up to the point of how to deal with the toilet supply line. Why is it hot water? Has it always been this way? If so the previous owners must have noticed. This house is 98 years old I cannot figure out how the line has been hot the entire time. How do I switch this to the cold water? There is no access panel in the bathroom and the line comes up through the floor. The bathroom is on the second floor and I can access plumbing in the basement. Where do I start? What do I look for? How do I fix it? Thanks to anyone with info.

Are you sure that the commode is the only thing that has hot water going to it? There has been cases where the hot water got too hot and backed up hot water into the cold water lines. So that is the first thng I would check.

If there is some way to trace the water pipes from the basement look to see if there are any branches off the pipe that goes up to the commode.

Give us more info and maaybe we can help.

Oh has there been any new piping been done on your house.

It is either failing mixing valve or crossed h/c lines...

FWIW: mixing valves are sometimes used on toilet supplies to make the water warm so the bowl doesn't sweat. It's not common.

FWIW: mixing valves are sometimes used on toilet supplies to make the water warm so the bowl doesn't sweat. It's not common.

It may not be common practice but I've seen a toilet tank mixing valve,(see image) installed. If you had one you would see two pipes coming out of the wall going to this valve and one leading to the tank. The only other explanation is that you have a cross connection. In that case you will have to track the toilet supply back to its source. Good luck, Tom

Turn off cold water input valve to water heater. Open hot side of a faucet, let pressure off line. Flush toilet, see if toilet refills. If toilet does not refill, toilet is plumbed to hot water line.