Water Pressure Question?

During an inspection today when I checked the pressure, my gauge read 120psi. WOW! I went to another bib, ran a little water, and rechecked it. It then read 60. Went back to the first bib, 60 also. There was a pressure tank on the supply side of the gas HWH. Why would the pressure be so high? could it be from a faulty regulator?

I don’t think 120psi would be enough to activate the TPR valve, so it could be possible that when the hot water heater kicked on the pressure could have increased. The pressure tank would have a small amount of supply at that pressure, but when you ran the water it de-pressurized the tank.

Sounds like it was working properly. Most houses (here at least) to not have any backflow prevention at the meter, so we don’t get that happening. Many regulators do allow backflow, but not all. That is the purpose of having the tank.

Thermo expansion?

That’s what I was thinking too. Either that or a failing pressure reg. The gauge pic will make a great pic for my site.

One hose bib may be on the supply side of the incoming water line, and the other on the downside of the water pressure regulator, if there is one.

I thought of that but I could shut it off in the garage, so that would rule the before out.

Recommend installing an expansion tank at the WH.

Sometimes the Seat/Stem module can be faulty or have some debris (typical of “creeping”) at the Pressure Reducing Valve/ or Regulator.

Only mentioned as quickly running some water can temporarily resolve this, then the pressure will “creep” back up. Could be a couple minutes… could be hours.

I’ve made a habit and leave my Pressure Gauge on the Bibb for quite some time. Even the $15 ones have a red sweep on them, indicating the highest pressure measured during the time you left on. This can indicate creeps or increase in water pressure that may be of concern.

Water pressure probs can be a little tricky.

Report issue and defer to plumbing or qualified contractor/technician and limit the amount of “fix” prescribed to or for the contractor. Negative results can happen from recommending “fixes”

ie… Recommend a repair to X Widget as it makes sense too. Y Widget was the real problem at 5 times the cost.

Mr Inspector… I woulda called someone, but YOU were pretty sure that the X Widget was no good!

We all want to help people solve their problems, just don’t create one for yourself.