Very unusual water meter reading

Users who are viewing this thread

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Hi all,

I'm a doctor living in San Diego (i.e. have very little plumbing knowledge) and I went to check my water meter for leaks and found something unusual.

During the nighttime and in the morning (before people have showered), the meter's flow indicator triangle is perfectly still. No movement of water into the house.

Then sometime in the late morning after everyone has showered and use the toilets, faucets, etc... the water flow triangle spins continuously throughout the day at a very very slow and steady rate. The last time checked was around 8pm after I had used the toilet for the last time. Triangle was still spinning slowly after that.

Then at night time again at some point it stops spinning.

I tried isolating the home by turning off the main shutoff in the garage and I get the same results. Slow spin during the day, still at night.

Then I tried a different experiment. In the morning when it is still, I flushed the toilet just once to see what happened. The meter slowly began to spin like it does during the day, then kept slowing down until it stopped right at the exact amount of water used by the toilet (0.16 cubic feet ~1.2 gallons).

So I've been thinking of a few possibilities:

  1. I have a leak in the main water line somewhere between the street and the house (since the meter spins when I turn off the main shutoff valve in the garage). But this wouldn't explain why it is still in the night/mornings. If there was a leak it should be continuous, no? Also I am assuming it can't be sediment lodging or dislodging on a pinhole leak because the meter was spinning after the last water use at night. So presumably it stops on its own at some point in the night without external influence. Furthermore, my water bill has not been significantly different than before. I have not noticed any visible water issues or pooling in the front yard but I do have turf all across so maybe it's something I'm not seeing underneath. Again, wouldn't explain why the meter doesn't move at night and in the early morning.
  2. The water heater is filling slowly during the daytime after everyone showers and uses hot water?
  3. There is a faulty PRV or faulty shutoff valve that trickle feeds into the house due to the pressure differential?
  4. The expansion tank next to the water heater is filling?
  5. Faulty meter?
At a loss as to how to explain this phenomenon. I could call in a leak detection specialist, but wanted to see if it was something I could figure out myself with your all help. I also have turf in my front yard and would hate for all the landscaping to be demolished and concrete drilled through in order to find a leak that isn't there.

Has anyone seen this phenomenon before? Have any ideas on what could be causing it? Any next steps I can take to further my diagnosis before I call in a leak detection specialist?

Thank you all!
 
Last edited:

Tuttles Revenge

In the Trades
Messages
3,162
Reaction score
1,021
Points
113
I think first I would verify that your main works 100% by shutting off your main, relieving pressure at the highest fixture in the house, turning that fixture off, wait a period of time, then open that fixture again and see if the water system has pressurized again. If not, then I would move on to verifying whether there is a leak in the water main between the main shutoff and the meter.

By shutting off your main in the house and the shut off at the meter. Wait a period of time. turn on the meter and see if water rushes in. If there is a leak, it will depressurize that section and refill when you turn the meter back on.

(removed redundant info)
 

Jeff H Young

In the Trades
Messages
6,118
Reaction score
1,394
Points
113
Location
92346
Some interesting Ideas Bearman several can be discounted. but you need to really confirm the suggestions by Tuttles. assuming shut off valve does its job . PRV bad not an issue, water heater filling definitely not the issue
We have smart meters here and water company can tell us how much water we are using at specific times . like one gallon used from 2 am to 220 am. I had a customer paying plumbers to guess and try finding a leak similar to your issue we had small amounts being used , I determined it was outside the house and not inside it had a separate valve to irrigation sprinklers with a valve right at the main that was malfunctioned. I recommend replacing that valve so we could shut off irrigation replaced valve closed it and water usage stopped, though this didn't fix the leak As I told customer more time is needed to find and repair but they were satisfied weren't using sprinklers and could open valve, water yard and close valve again as it was a very small leak at weird hours no idea why it started and stopped during day or night I suspect pressure or temp fluctuation
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
I think first I would verify that your main works 100% by shutting off your main, relieving pressure at the highest fixture in the house, turning that fixture off, wait a period of time, then open that fixture again and see if the water system has pressurized again. If not, then I would move on to verifying whether there is a leak in the water main between the main shutoff and the meter.

By shutting off your main in the house and the shut off at the meter. Wait a period of time. turn on the meter and see if water rushes in. If there is a leak, it will depresurize that section and refill when you turn the meter back on.

(removed redundant info)
I think first I would verify that your main works 100% by shutting off your main, relieving pressure at the highest fixture in the house, turning that fixture off, wait a period of time, then open that fixture again and see if the water system has pressurized again. If not, then I would move on to verifying whether there is a leak in the water main between the main shutoff and the meter.

By shutting off your main in the house and the shut off at the meter. Wait a period of time. turn on the meter and see if water rushes in. If there is a leak, it will depresurize that section and refill when you turn the meter back on.

(removed redundant info)
Thanks for the response!

So the only snag in that plan is the property side shutoff lever at the main shutoff has been broken for years. I've never fixed it because I have a house water shutoff in the garage. So felt it was redundant to fix. So if I needed water to shut off at the street, it would have to be done on the city side of the meter. Which I don't have access to the tool needed.

I checked the meter again just now (9:40pm PST) and after the laundry machine had run for a bit, the meter slowly moved for a couple minutes before stopping completely.

I guess my main question is, since the meter eventually comes to a stop, whether it's a few minutes later or several hours later by the next morning, should I really even be worried about a leak? Since with leaks, it should be a continuous movement? Can this just be some sort of pressure issue in the system that doesn't have any significant effect? I mean my bill isn't even changed, so I wonder if I'm reading too much into it.

I guess I'm looking for reassurance as much as I'm looking for guidance.

Thanks so much again!
 

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
Bearman731: Do you have an irrigation system, such as a sprinkler system? If so, do you have a valve that can shut off the feed to that?
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Bearman731: Do you have an irrigation system, such as a sprinkler system? If so, do you have a valve that can shut off the feed to that?
I used to have a sprinkler system but they turned it off and capped it when we installed turf. I also disconnected the circuit board that controlled it too. So doubt the old sprinkler system has gone rogue.

For what it's worth, for the past hour the meter has been completely still.
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Another idea I had was:

What if the property side street shutoff valve (which has been broken for years), is in a partially open position. Such that when the entire system is pressurized and when a toilet is flushed, nothing abnormal happens, but it takes a while for the pressure to equilibrate because the valve is not 100% open. That could also explain why the meter also sometimes runs even when the garage shutoff is turned off, because the water still has to equilibrate in the main line between street and garage. It's the only diagnosis I can think of that unifies every occurrence.

Because otherwise, there doesn't seem to be a leak. For the past hour the meter hasn't moved at all.

Thanks for all the suggestions and tips so far!
 

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
Test the garage valve by shutting that. Open a faucet and after maybe 30 minutes, measure how much water comes from that open faucet in a time period, such as an hour. If that valve leaks, that will affect your sleuthing.
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Also forgive me for any misunderstandings on my end or even not describing things the right way. This isn't my area of expertise so just trying my best :)
 

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
So I agree we can logically infer, as you stated in #1 item 4, in that whatever weird thing is going on, it is going on upstream of the garage valve. I agree with your analysis. I was wondering if the leakage was somehow triggered by higher pressure, but pressures are more likely higher in the middle of the night rather than days.

So some leak that only occurs in higher sunlit daytime temperatures? I have a hard time picturing what could cause that.

I am eager to hear what the deal was if you get this figured out.
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Can weather play a role in any of this? The meter just started spinning again ever so slightly. It was raining earlier but now things are starting to dry up (although slowly because it's still cloudy). I'm struggling to figure out why the meter would be spinning again.

I'm inclined to think it has something to do with the valve at the main shutoff on the street. Perhaps because it is broken could it be in a semi-open position which makes the flow responses not instantaneous?

Another thought I had was, do the copper pipes in my house expand with rising temperatures? Could that then draw in more water to equilibrate the system?

Any chance a faulty PRV cause this? Where it leaks into the house, but when pressures are at equilibrium (such as at night with no activity), it doesn't affect it?
 

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
PRV is located where-- near the meter? If it leaked, would you see that? I don't really see the PRV doing this.

The main shutoff would be before the meter, according to my semantics.

While copper expands with rising temperature, water expands more.
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
PRV is in the garage near house shutoff valve there.

My meter has two shut-off valves. One before the meter (street/city side) and one immediately after the meter (property side). The property side meter doesn't work (been broken for years). But it doesn't matter because I have a whole house shutoff valve in the garage. The PRV is in the garage right after this house shutoff valve.

So I just checked and the meter stopped spinning now. It was slowing down almost imperceptibly until it stopped. I'm inclined to think it has something to do with equilibration of pressures now and not a leak. A leak should be continuous flow. I've also noticed a couple interesting behaviors:

When I run smaller things just once, like a toilet for example, the triangle runs initially fast during the rapid consumption phase, and then it slows down. It keeps slowing down to an inevitable stop within minutes.

When I run something more substantial or in multiple consecutive times, like a washing machine, followed by bathroom a couple times, followed by using the faucets, etc... The meter keeps running slowly for a while afterwards, even upto an hour until it finally stops.

I suspect the reason it is completely stopped in the early morning is because it's been hours since water was last used. So it had time to settle down to zero.

The fact that water keeps coming in slowly AFTER the appliances are done being used, in proportion to the amount of time and water the appliances used, leads me to think that the meter is "catching up" to the losses. I.e. there is some sort of equilibration happening until the pressures are similar enough that there is no more flow registering.

Since the meter inevitably comes back to zero, even during the daytime now, I am less inclined to think it is a leak. And rather an equilibration issue.

What do you think?
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Can that happen, where the house pipes need time to get "refilled" until the pressure is equivalent everywhere? And that could cause a delay in the water meter returning to zero movement?

Or another thought is, if the pressure in the system is dropping with water use, does water need to continue running into the house to repressurize the expansion tank?
 
Last edited:

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
Can that happen, where the house pipes need time to get "refilled" until the pressure is equivalent everywhere? And that could cause a delay in the water meter returning to zero movement?

Or another thought is, if the pressure in the system is dropping with water use, does water need to continue running into the house to repressurize the expansion tank?
Water is nearly incompressible, so the time to re-pressurize would be tiny. I was going to say "minute", but that might be confused with 60 seconds, and we would be talking milliseconds. https://grammarist.com/heteronyms/minute-vs-minute

The thermal expansion tank air precharge should be set to the PRV regulation pressure, or a tad higher. So that tank should stay empty of water during any refilling that might go on.
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Water is nearly incompressible, so the time to re-pressurize would be tiny. I was going to say "minute", but that might be confused with 60 seconds, and we would be talking milliseconds. https://grammarist.com/heteronyms/minute-vs-minute

The thermal expansion tank air precharge should be set to the PRV regulation pressure, or a tad higher. So that tank should stay empty of water during any refilling that might go on.

Let's say hypothetically if I mucked around with the PRV (actually not a hypothetical situation, this actually happened) and didn't take into consideration the expansion tank, could the expansion tank then be filling? Basically wondering whether any sort pressure differential can cause water to keep moving in?

I tested the meter out again today:

1. Meter was completely still
2. Took shower and afterwards meter started turning
3. Triangle kept turning very slowly
4. Turned off main water valve in garage
5. Meter kept turning very slowly until it eventually stopped.
6. Turned on upstairs most distant faucet until it stopped running.
7. Then turned the garage valve back on (heard a woosh of water come in)
8. Meter started spinning again and then slowed down until it eventually stopped.

How can I make any sense of this? The fact that it inevitably comes to a stop tells me there's no leak anywhere. But why the delay in stopping?
 

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
Check the air precharge on the thermal expansion tank while the water pressure is zero.

If the water pressure is higher than the air precharge, the air pressure will be close to the water pressure. Why only close? The diaphragm in the tank is not perfectly limp.

7. I expect that woosh was quick, but if the air precharge is lower than the water pressure setting, then the woosh would be longer than it otherwise would have been.

8. How long? Does this meter appear to be totally mechanical, or does it have an electronic display? I expect mechanical, based on your words.
 

Bearman731

New Member
Messages
21
Reaction score
1
Points
3
Location
San Diego
Check the air precharge on the thermal expansion tank while the water pressure is zero.

If the water pressure is higher than the air precharge, the air pressure will be close to the water pressure. Why only close? The diaphragm in the tank is not perfectly limp.

7. I expect that woosh was quick, but if the air precharge is lower than the water pressure setting, then the woosh would be longer than it otherwise would have been.

8. How long? Does this meter appear to be totally mechanical, or does it have an electronic display? I expect mechanical, based on your words.
7. Woosh was really quick. Almost instantaneous as I turned the valve.

8. Probably on the order of 3-4 minutes? I should've timed it. It moved approximately 0.17 cubic feet of water from the woosh to the time it stopped turning. Meter is mechanical.
 

Reach4

Well-Known Member
Messages
36,691
Reaction score
3,915
Points
113
Location
IL
3-4 minutes is a lot more than I thought you were going to say.

You might ask the water department. Maybe they will say it is normal for that meter, but I don't know what the mechanism would be.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks