Pressure reducing valve and Neptune water meter

Joined
Jul 14, 2020
Messages
28
I just thought I would post this to see if anyone else had run into this problem. I noticed the red dial indicator continuously turning on my water meter , indicating water running even when no faucet or other device was on. Points to a leak. I checked the water pressure and saw it to be 100 psi when the pressure reducing valve is set for 55 psi. This tells me the PRV is bad, so I thought that would be where the leak is. The PRV is 3 feet from the water meter underground. I dug up the PRV only to see it dry. Still, since it is not regulating properly, I replace it. To my surprise, even though the old PRV was not leaking, putting in the new valve stopped the indicator on the meter from turning. To sum it up, the defect in the PRV was somehow causing the water meter to register water running when it was not. This was a Neptune water meter. This amounted to approx. 1000 to 2000 gal. per month on my bill. While not that much money, I still wanted the problem corrected.
 
If I understand your post correctly the PRV is before the meter? If so wouldn’t that be something your water provider is responsible for?
 
  • Like
Reactions: hrv
I'm not a plumber, but a hydraulic engineer...so comments come from my experience in hydraulics.

If the pressure reducing valve is actually a pressure reducing and relieving valve (which would be safer for the downstream system), and it was downstream of the meter, I could see it dumping flow "to tank" (sewer?) if it was malfunctioning.
 
If the pressure reducing valve is actually a pressure reducing and relieving valve (which would be safer for the downstream system), and it was downstream of the meter, I could see it dumping flow "to tank" (sewer?) if it was malfunctioning.

I've never seen a PRV used in residential applications that is also a relief valve. I have seen them used in commercial applications.
 
I'm not a plumber, but a hydraulic engineer...so comments come from my experience in hydraulics.

If the pressure reducing valve is actually a pressure reducing and relieving valve (which would be safer for the downstream system), and it was downstream of the meter, I could see it dumping flow "to tank" (sewer?) if it was malfunctioning.
I have seen those in commercial apps (we have one at work)
but not residential.
 
I've never seen a PRV used in residential applications that is also a relief valve. I have seen them used in commercial applications.
Years ago I was doing work at a place where a plumber was replacing a PRV. I didn't know much about them at the time, so he was happy to tell me about them. He said they use them in areas where the water pressure is abnormally high, coming into a residence. like if you lived in a town where they had a water tower. Just the normal pressure from the tower would cause problems if it wan't reduced after it left the tower. The closer you lived to the tower , you could see main pressure up to 200 psi. That would blow most household plumbing apart.,,
 
Years ago I was doing work at a place where a plumber was replacing a PRV. I didn't know much about them at the time, so he was happy to tell me about them. He said they use them in areas where the water pressure is abnormally high, coming into a residence.

I bought a house in Spotsylvania County, Virginia. The location is important, because I think it explains a lot about what happened. I noticed that the water pressure coming into the house was VERY high. It pegged a 100PSI gauge. I called the water company, which is part of the county government, and asked what is going on with the water pressure. The lady who answered the phone said, "Oh, we made some changes to our system. You can call a plumber to get a pressure regulator installed".

Absolutely no care given, let's just "make some changes" and potentially damage the customer's plumbing. Nobody I talked with in the neighborhood had any idea that their water pressure had increased, or that it could cause damage. (I would expect, if the water company weren't run by complete morons, that they'd at least have let the affected customers know...)

Worth noting that the house was built in 1975 and this happened in 2002.

I called a plumber to install a PRV and the plumber also had to come back to install an expansion tank on the water heater because a PRV absolutely prevents any backflow out to the main, so the water heater's TPR valve would sometimes drip. The expansion tank fixed that.
 
the water heater's TPR valve would sometimes drip.
This^^^ as No. 1 suspect. Beyond that look at any other automatic valves you may have . Sprinkler shutoff valves, toilets tanks that are always full to overflowing. Hissing sounds coming from the washing machine etc. If your water heater has a catch pan plumbed to drain make sure it is dry.
 
If I understand your post correctly the PRV is before the meter? If so wouldn’t that be something your water provider is responsible for?
Thanks for reading, but the PRV is after the meter, between meter and house.
 
Water services can be a pain to deal with. I had a water leak on the company side of the meter. They came out and replaced the line that services my meter. Great, everything was good. First thing I noticed all of the hot water faucets in the house started to seep. I thought OK, no big deal, they were all old and probably needed new parts. Then the hot water heater started leaking and not from the pop off valve. Again OK the thing was about 15 years old. Replaced the water heater and when I got it up and running the pop off valve was seeping. At this point (I'm slow) I decided that something is not right. Went out to my meter and spotted a new device installed on the company side of the meter. Called the company and they said yes we installed a check valve and they are required to it any time they service a meter line. It turns out I needed to install an expansion tank. What the heck! If they had just told me what they had done. With the check valve the pressure in the house plumbing would sky rocket when the water heater got the hot water temp up. The system had no way of absorbing the expanding water. Expansion tank cured the problem.
 
Thanks for reading, but the PRV is after the meter, between meter and house.
Here is Louisville the PRV is located before the actual water meter...So THEY are responsible for repair on it. I know because I had mine replaces a few years ago.....They do go bad over time....Anything AFTER the water meter is your responsibility...
 
Do you have a expansion tank on the cold water line off water heater? Need to check its operation. 60 lb water pressure set tank pressure at 60. Get any water out of air side tank is bad needs to be replaced.
 
  • Like
Reactions: hrv
I just thought I would post this to see if anyone else had run into this problem. I noticed the red dial indicator continuously turning on my water meter , indicating water running even when no faucet or other device was on. Points to a leak. I checked the water pressure and saw it to be 100 psi when the pressure reducing valve is set for 55 psi. This tells me the PRV is bad, so I thought that would be where the leak is. The PRV is 3 feet from the water meter underground. I dug up the PRV only to see it dry. Still, since it is not regulating properly, I replace it. To my surprise, even though the old PRV was not leaking, putting in the new valve stopped the indicator on the meter from turning. To sum it up, the defect in the PRV was somehow causing the water meter to register water running when it was not. This was a Neptune water meter. This amounted to approx. 1000 to 2000 gal. per month on my bill. While not that much money, I still wanted the problem corrected.
I'm actually in the beginning stages of dealing with something like this.

I have the electronic Neptune meter outside and all of a sudden, last month we started using about 4000 gallons more water than normal. That sort of got my attention and I made sure everything was off that should be, including a dripping hose barb, and didn't think any more about it until I got my water bill this month, which was 6000 gallons over what we usually use.

Water company sent me a data pull of the meter which shows the last 3 months broken down by hour. Almost EVERY single day at 1am - 5am the meter reports between 25-50 gallons of water being used. Of course, their response was 'its on your side of the meter'.

I'll definitely check the pressure at the house. I'm pretty sure my PRV is in the garage as memory serves. (yep)

I might just replace it anyways since it is easy to get to. I wonder if the backflow valve has given it up and water moving back and forth is adding up.

1704531135224.jpg
 
Last edited:
If I understand your post correctly the PRV is before the meter? If so wouldn’t that be something your water provider is responsible for?
If it is before the meter they should fix it not you....
 
shut water off to prv,mark the adjusting screw position and work screw up and down a few times,put back to marks on screw pressure setting ,,this may free up the diaphram,as it may have deposits,disconect and flush,,also some prv valves and meters have screens at inlet port,clean this,,some systems may have a watts (brand) back flow preventor valve also, do you have a pressure gage in the down side of meter?? the prv should be before the meter possibly with a by-pass line/valves (tagged) depending on your local codes.also if suspected you can request a meter change out with your local water dept if readings are too high or continually adding meter totals from times past.or with the downside (after meter) ,close valve ,mark the meter,then wait a few hrs to see if still adding,
 
shut water off to prv,mark the adjusting screw position and work screw up and down a few times,put back to marks on screw pressure setting ,,this may free up the diaphram,as it may have deposits,disconect and flush,,also some prv valves and meters have screens at inlet port,clean this,,some systems may have a watts (brand) back flow preventor valve also, do you have a pressure gage in the down side of meter?? the prv should be before the meter possibly with a by-pass line/valves (tagged) depending on your local codes.also if suspected you can request a meter change out with your local water dept if readings are too high or continually adding meter totals from times past.or with the downside (after meter) ,close valve ,mark the meter,then wait a few hrs to see if still adding,
At least in my case, they won't replace the meter. They swear it is a leak on my part. The pattern in the log is too repeatable to be a leak IMO, not that I'm a plumber or anything.

Almost every single night repeats this pattern. The only thing that should draw water at night is the icemaker, or a toilet if one of us gets up to flush. We don't have a water softener, sprinklers, or anything like that. And according to my cameras, no one is sneaking up to the house and stealing water.

The only other thing I can possibly think of is that there is a leak, and system pressure creeps up during those hours of low demand overnight and the leak flows more...I'm not convinced that is possible, but that is the only other thing I could think of until I stumbled across this post. There are a few mentions online as well of Neptune meters reading pressure fluctuations as flow and people replacing a backflow preventer.

In our county they are in the home, not at the meter as far as I'm aware of.

1704536077442.png

1704536049721.png

1704536020636.png
 
before you go turn in at nite,first check if everything is off sink fawcetts etc,and make sure toilet is not leaking,,wait a while or in the am see if there is still pressure in the lines,if not something is draining off line,then one by one,isolate the toilets first,ref,ice wash machine humidifiers etc supply lines and other suspecting plumbing fixtures to locate problem,,,,,,also add a gauge in line may help,the water pressure is usually higher at nite to note
 
before you go turn in at nite,first check if everything is off sink fawcetts etc,and make sure toilet is not leaking,,wait a while or in the am see if there is still pressure in the lines,if not something is draining off line,then one by one,isolate the toilets first,ref,ice wash machine humidifiers etc supply lines and other suspecting plumbing fixtures to locate problem,,,,,,also add a gauge in line may help,the water pressure is usually higher at nite to note
For the toilet put a few drops of food coloring in the tank and DO NOT flush it....When you get up in the morning if the water is clear in the bowl no leak...if you see color in the water it is leaking most likely the flap area....
 
Dye test was the very first thing I did. Both passed over a period of 6 hours.

I've already ordered the parts to replace my BFP/Regulator. The house is watertight and the pattern of the late-night 'usage' just speaks to something that isn't a leak. (Especially if the toilets are not flowing). If it were a leak in the main it should be flowing all the time to some extent. There's no way it would be 0 flow some parts of the day and then just start leaking overnight.

Hope to have it replaced on Monday and will have the water folks pull another data dump later in the week.
 
Years ago, our water company would make some operational change late at night that made the supply pressure swing up and down 40-50 lbs every few seconds. It made the copper pipes creak in the walls and the water heater make stress noises.

If your supply has pressure fluctuation AND your PRV is stuck, AND you have an expansion tank on the water heater, it will generate a small flow on each swing as the expansion tank pressurizes. I have no idea what happens with the meter when the pressure drops and the flow reverses, whether the measurement reverses or locks in place.

In my case I didnt experience any metering problems from the pressure swings because there was no PRV or expansion tank on our house at the time. (I quickly added both, however, to prevent the pipes from fatiguing from the flexing.)
 
Back
Top