For last couple weeks, have had to turn on a second faucet... both upstairs on down, to get hot instead of lukewarm water... such as sink to get hot water for shower, or second sink to get hot water for kitchen sink

Is there a hot water recirculating system installed? Back to you, Tom

Tom, it is just a regular hot water heater, which it in the laundry room area of the garage... about 30 feet away from the entry to dining room and kitchen.

You may have a bad single handle cartridge in any of your fixtures that is allowing cold/hot to flow through creating a cross connection. Go to any sinks with single handle faucets and shut the valves below the sink off and see if things improve at other fixtures. Do one sink at a time to find the culprit. Also try shutting off washing machine valves. It may also be a shower or tub fuacet causing the issue, but they usually don't have individual shutoffs, so you may need to simply replace the cartridges in those if none of the sinks do the trick.

Thanks, will print this and check it. Will have to get back to y'all this weekend. Not really sure how this would explain it happening to all areas... kitchen, upstairs bedroom, and both downstairs showers...

A bad single handle cartridge in only fixture in the home can effect all fixtures in the home. And quite honestly, it can be a pain to track down sometimes, especially if it's a tub/shower valve with no individual supply shut offs. At least in a residential home, its just a matter of eliminating one fixture at a time, and there aren't too many to deal with. I get these calls in an assisted living home now and again with many many fixtures to eliminate. Time consuming to say the least, not to mention there are multiple recirc lines with multiple check valves and pumps which really can make the trouble shooting interesting. So far I haven't been completely stumped, at least not for more than a day or two, lol.

OK... so this means I have to go to every fixture and... do what??

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