Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

BruceWard · Apr 29, 2011

I have 660' of 2" gasketed SDR17 water line in the ground. Watching the meter it spins about 2.5 gallons per hour. I have two hydrants attached to the line. I turned off shut off valves on the hydrant Ts and the water usage continued.

We have had 8.5" of rain in the last 2 weeks. The ground is so saturated that any leak would not be visible. Maybe the leak will show itself as the ground dries out in the summer.

The water line has over 80 PSI at the high end and closer to 90 in the middle.

Looking at my meter there is a small red wheel that registers hundredths of a gallon. I have seen this wheel spin in both directions. I do not know if the gallons used readout also spins backward.

My line is connected to a 8" main line with few homes connected. Likely less than 10 within a mile. The elevation changes as much as 100' within a mile.

I suspect that when the pressure on the main line increases additional water flows into my 660' x 2" 110 gallon line then when the pressure decreases water backs out. If the meter only registers water coming in then I may be paying for water I am not using.

I would appreciate your advice on whether or not it may be a metering issue and any methods of fixing or finding the leak.

Thanks

beeforty · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

I would make sure that the gallons used goes backwards!! If it doesn't then maybe what is happening is as your pressure builds up in your line it charges you for use, but when some else uses water and system pressure drops on your line and you have no demand for water use, the water flows back out of your line somewhat like a pulsing pressure pump. Maybe you are being charged for water pulsation

Might want to put a one way check valve in to make sure there is no back flow if you don't find any leaks.

CurlyDave · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

What is your water billing rate?

Typically it is less than $1 per 100 cubic feet. There are 7.8 gallons per cubic foot, so it might be as little as 0.1 cent per gallon. Even at a much higher rate, finding a leak in this line would be just about last on my priority list -- right after washing the old aluminum foil so I could re-use it.

Monitor it and see if it is increasing, which might be a concern, but 2.5 gallons per hour is not that much water.

LD1 · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

BruceWard said:
I suspect that when the pressure on the main line increases additional water flows into my 660' x 2" 110 gallon line then when the pressure decreases water backs out. If the meter only registers water coming in then I may be paying for water I am not using.

beeforty said:
I would make sure that the gallons used goes backwards!! If it doesn't then maybe what is happening is as your pressure builds up in your line it charges you for use, but when some else uses water and system pressure drops on your line and you have no demand for water use, the water flows back out of your line somewhat like a pulsing pressure pump. Maybe you are being charged for water pulsation Might want to put a one way check valve in to make sure there is no back flow if you don't find any leaks.

Not likely.

Water does NOT compress. Unless there is air entrapped in the line.

So it wouldnt matter wether there is 10psi or 100psi, the volume of water in the line would be the same. So I doubt that a pressure change would cause you issues.

Is there a shutoff valve BEFORE the meter anywhere?? I would think there would have to be. How else would the water company ever change out the meter?? So if there is, try shutting it off and see if the meter stops. If it does, my money is on a slow leak somewhere.

Curlydave, I disagree.

2.5gph IS a lot of water usage. About 1800 gallons per month:confused2:

My family of 3 only uses 3000-4000 gallons per month. And my bill is $20-$25 Not sure how much he uses, but I would certainly be concerned if my usage was up 50%. That would amount to about $10-$15 per month for nothing.

BruceWard · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

There is a shutoff valve before the meter. When I shut it off the meter stops turning as expected.

I pay about $4.50 per thousand gallons. So it is a $9 a month problem that would likely cost many times that to fix.

It is likely that some air is trapped in the line. I do not have a hydrant or any opening at the high point in the line. I have run a thousand or more gallons through the line since the last splice but I still get bubbles at the last hydrant which is down hill from the highest point. I ran the water at full blast (20 GPM) for 5 minutes to try to clear out the air last week but still have some bubbles.

I have seen the red wheel on the meter spin backwards several times so I know water is backing out of my line. I have dual check valves on both hydrants but not on the main line. This is how the city wanted it.

LD1 · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

I would put a call in to the city to find out exactally how their meter works.

If it is just air in the lines compressing and decompressing causing water to flow back and forth across the meter, and there meter registers both directions, then you arent being charged and its a non-issue.

But if you are being charged, that is an issue. And since you are seeing 2.5gph register on the meter, it sounds like there is either a leak, or the meter only reads one way.

But I'd call the city first to confirm how the meter works, cause if they verify that it reads one way only, you know you have to work on your air problem. If they confirm that it reads BOTH directions, then you have a leak somewhere.

jmanatee2 · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

if there were air trapped in the line or an expansion tank, it could allow for pulsation that would register on the meter. I believe water meters are like a disk and it doesn't care which way water is flowing.

You could add a check valve (pretty cheap) right after the meter this would stop and pulsing measurement.

Gary Fowler · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

There are some very sensitive microphone type leak detectors that will find just about any leak. We hired a company to find a leak on a 36" buried cooling water line that was 15 feet under ground and he not only found the major leak which was a blown gasket but could also detect drips of not more that 1 drop per minute. He said he could hear it when it dropped off the flange into the soil underneath. I couldnt verify that because we didnt dig up any other parts, but he was right on the money with the location and leak on the blown gasket. The device he used was not much bigger than a 2 way radio with a set of head phones and a section of metal probe that he simple place onto the firm soil. There was equipment running all around and it didnt bother the test. Might be a little expensive to your leak.

BruceWard · Apr 30, 2011

Re: Finding 2.5 GPH Water Leak in 660' of 2" Gasketed Pipe or is it a metering issue

Gary, I am in Hot Springs. If you still have the name of the company you used could you let me know who it was. That sounds like the perfect solution.