So I recently moved into a duplex and everything is good except that the shower water temp fluctuates. It gets warmer fairly soon after starting my shower. The water pressure seems good. At least the hot is. I have my own water heater and there is no one else in the unit so no one flushing or using water but me.It is an old three handle setup with a diverter and a hot water knob and a cold water knob. Any ideas why I lose cold water?

There is possibility you have a loose washer on cold water stem

Milo

I think you said it best when you said it was old, and maybe needs some maintenance. Do you own, lease, or rent? The status is important as to how you go about rectifying this, and any other issue you come across. Owners can fix their own stuff but renters and leasees are bound by whatever terms their contract states.

Which are you?