I have searched all over the internet and consulted 2 plumbers to try to fix this issue. I am not a plumber; however, I am an apartment manager with a frustrated maintenance tech and even more frustrated resident. The apartment has a 40 gal water tank. It was installed 2 years ago. The tenant has just within the past week complained of her cold water being warm/ hot from the cold side of her faucets...all of the faucets. There are no single faucets - all Deltas 2 knob, separate hot cold supply lines. There are no mixing valves to check other than the washing machine. Which we shut off the water there to see if that was the problem; however, she is still experiencing warm water. We shut off the water from the water heater. Still, warm water coming from the cold side. This is an upstairs apartment. Water in other apartments is cold. The last time any kind of plumbing work was done was replacing a cold side stem in the bathtub faucet to fix a dripping faucet, not a single handle faucet either. Any other suggestions??

usually that means the warm air is heating the water in the pipe before it reaches the apartment.

Water in other apartments is running cold like it should be though.

Tempering valve on the toilet supply? Thermostatic mixing valve on the water heater?



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Your original posting does not give us anything to base a diagnosis on, and just because the other apartments do not have the problem does not mean the piping was installed the same way in all of them.

water bypassing at shower valve ?!

if water heater inlet valve is actually shut AND HOLDING you have either:

a cross connection with another unit

or

a 'sensitive' tenant not accustomed to 'southern' summer water

or

gremlins

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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They stated that all the faucets are two handles which cannot bypass.

I don't think the toilet has a tempering valve but will double check with maintenance on that. Isn't the tempering valve used to lessen condensation on toilets?

I will ask maintenance to check the thermostat valve on water heater. Thanks for the suggestions!

Both would be very rare in an apartment situation.