Thread: City water main not cold

I am in New Jersey. I checked this house and the water coming in from the city main was cool not cold. Any thoughts?

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If it's been real hot (and I hear it has been rather brutal up there the past week or so) and if the pipe is not real deep in the soil, then the pipe could very well warm up and warm the water up too.

I'm in SE Pennsylvania Martin so I'm not far from you. I see this condition in my own house when the outside air temperature hits "broiling" like we've had lately. And in the dead of winter, cold water is real cold.

Originally Posted by Martin Muth

I am in New Jersey. I checked this house and the water coming in from the city main was cool not cold. Any thoughts?

I was in Texas once, went to the motel, turned on the "Cold" water---it was warm. Turned on the "Hot" water---it was hot. Called the front desk---they said that the pipes there are not that far down in the soil. In the summer, the "Cold" water is warm due to the soil heating up. Everyone keeps water in their frig to have "Cold" water. Maybe you have the same situation there. However, I live in NJ and my Cold water is cold, not as cold as it is in the winter, but it's cold---not warmish.

Originally Posted by Nick Ostrowski

I'm in SE Pennsylvania Martin so I'm not far from you. I see this condition in my own house when the outside air temperature hits "broiling" like we've had lately. And in the dead of winter, cold water is real cold.

Same here. We're at that time of year when most showers I take are "cold" only, and I'm disappointed that the water is barely cool.

Living in Phoenix, I have learned that warm water in the summer only comes out of the cooler and fridge.
If you have piping in your attic, you don't even get that for the first few minutes - you can burn yourself with the initial run of "cold" when you turn on some fixtures.

Looks like you guys are having the same temps we are in FL now, normally we only get cold water in the winter Jan-Feb other wise it's somewhat warm... Enough so I rarely use the hot water when taking a shower. I can even feel heat radiating up from the toilet that's nearest the sewer main coming from the house when the lid is lifted! (very mild, but I can feel it with my hand when first opened in an air conditioned home.
Did you take a temperature reading to see how warm it actually is?

Might be expansion from the water heater.

Heat traps? expansion tank? Potential in house system for "crossover"? (Such as point of use or booster water heater devices, single handle faucets, etc.) Was the system "Open" or "Closed"? Metallic or "plastic"?


What was the size of the house main and distance from supply (city main)? Did you calculate the volume of water and flow rate to flush the system of stagnated water to actually determine the true "fresh" water supply temperature ?

I'll toss in a curve here. I had this situation once during the Fall - no warm weather. The client was the renter of the property who wanted to buy it. He said the "cold" water had always been warm during the 2 years he had lived there. I also found amperage on the incoming water line and the copper pipe was blackened from the point where it entered through the foundation to the grounding clamp about 15 feet inside the basement.

I have often found amperage on discolored copper water lines and in my view there is an association but no one has been able to explain it. The mere fact of having amperage on water lines is totally baffling to most of the techies at the utility and there has been a somewhat unofficial conclusion that it's not to be a worry. Now as far as whether amperage on a water line can heat the water - that seems so far out in left field I can't find a sole who can grasp that possibility.

Originally Posted by Eric Barker

I have often found amperage on discolored copper water lines and in my view there is an association but no one has been able to explain it. The mere fact of having amperage on water lines is totally baffling to most of the techies at the utility and there has been a somewhat unofficial conclusion that it's not to be a worry.

That could be from several causes: a) there is a ground-fault somewhere and current is on the ground when it should not be; b) there could be a neutral bonded to ground someplace downstream from the service equipment, and if far enough downstream, all grounded metal cases would have neutral current flowing through them, including water heater and their connected metal piping; c) there could be a bad neutral to the service and more neutral current is going back to the transformer through the ground than is intended (none is really intended, but there will be some); d) stray currents caused by the fact that the power companies only use a 3-wire service feed which forces some of the neutral current back to the transformer through earth from the grounding electrode system at the service; e) and there may be other causes.

Now as far as whether amperage on a water line can heat the water - that seems so far out in left field I can't find a sole who can grasp that possibility.

Not sure why that is so hard to grasp, that is precisely why conductor heat up when current is run through them, and that metal pipe is a conductor with current running through it - but it would take a fair amount of current to heat up a copper water pipe even without water in it, add water in it and it would take a lot of current to heat the pipe up (which would then heat the water up). What levels of current are you finding in the water pipes?

Originally Posted by Jerry Peck

Not sure why that is so hard to grasp, that is precisely why conductor heat up when current is run through them, and that metal pipe is a conductor with current running through it

Kinda my thinking too. I don't remember the amperage found. What would have been more useful is if I had been able to measure the voltage on the pipe.

How were you able to read the amperage? Did you use a clamp-on meter or did you get a reading some other way?

Originally Posted by Eric Barker

What would have been more useful is if I had been able to measure the voltage on the pipe.

The current would be more useful as, because that pipe is (is supposed to be) "ground", measuring voltage to ground would not produce much voltage at all, the only voltage you would read would be the voltage drop across the resistance in the copper pipe caused by the current through the copper pipe.

Originally Posted by Jerry Peck

The current would be more useful as, because that pipe is (is supposed to be) "ground", measuring voltage to ground would not produce much voltage at all, the only voltage you would read would be the voltage drop across the resistance in the copper pipe caused by the current through the copper pipe.

Had a situation once where equipment was acting strange. When the equipment ground was removed from the "Ground Bar" - trouble disappeared. Traced it to a faulty connection in an adjacent electrical substation 2000' from the building. You never know.

Year 1976, a bitterly cold winter in Washington DC. So cold that the Chesapeake Bay froze hard enough that people were driving their cars under the bay bridge.

So many water services froze that plumbing companies hired welders to thaw service lines by connecting arc welders to a hose bib at the house and on the meter yoke located in the meter pit at the street. A high amperage current between these two points would then thaw the line.

So, after saying all that, yes, a current running through a water service could indeed raise the temperature. But I would think only during times of no water flow as it would be a slow process.

I can’t recall how many craw spaces I worked in to repair pipes damaged from freezing.
Man, I don’t miss those days!

Many cities store water in above ground tanks. With the recent weather how hot/warm do you think these tanks are? I would think they would be a giant heat sinks that warms the water as it flows through it. That would be a reasonable explanation of why the cold water is tepid.

//Rick

If your municipality uses water towers, and outside air temperatures have been in the high 80's and 90's, your cold tap water will be "warm."

Originally Posted by James Duffin

How were you able to read the amperage? Did you use a clamp-on meter or did you get a reading some other way?

Clamp on meter