Finding and fixing a leaking pipe in a 20 yr old single story house

[xpate]

Hi, I have a leaking pipe somewhere inside the house. There is no visible evidence of its location but it is large enough to kick my pump on after 7 seconds. The pipe is PVC at the house supply point, so assuming PVC throughout. There appears to be just one run from front of house to rear of house and one branch to bathroom sink and shower, and maybe a T to feed the bathroom and also reach the rear of house. Total pipe length is 20 ft from intake front of house to split to bathroom, then 15 ft to outside of rear of house. The branch to the bathroom, which feeds the faucet, toilet and shower is 12 ft.

So my question, how do I find the leak, short of tearing up the whole house? I would think the leak is at a joint and the pipe layout seems rather uncomplicated. Are there any minimally invasive means to locate the leak?

Has anyone faced a similar experience? One last note, the trouble started after my wife installed an external water purification system, and the installers used an awful lot of solvent on their PVC subsystem. Afterwards the pump would cycle on for short burst every couple hours, I thought it was leaky toilet so I replaced the works. But this did not solve the problem and it has progressed to the point where we need to turn off the pump and water bill was sky high last month, lol. My feeling is that they did not flush the system adequately and this softened some joint and this progressed over time, is this feasible?

Thanks in advance for any suggestions or anecdotal experiences.

[cooked]

I had a similar experience, although we have no pump. I just short circuited the whole pipe along outside the house.

Now don't laugh: a friend of mine traced a leak using a pendulum. I'm not a superstitious person but it might be worth a try. I found my wallet after two days desperate searching, it was on top of a cupboard for some reason, the pendulum showed the right direction but not the height above ground, but I found it.

I believe plumbers sometimes use a stethoscope to listen for the hiss of running water.

[RichCor]

Once every 7 seconds sounds like a slow running shower, not a dripping leak.

You would think you could find it from the standing water.

Can you describe the "Water Purification System"? If it has a reverse osmosis component then this will dump lots of water out when back-cleaning the membrane.

[stoneyboy]

I had a similar experience, although we have no pump. I just short circuited the whole pipe along outside the house.

Now don't laugh: a friend of mine traced a leak using a pendulum. I'm not a superstitious person but it might be worth a try. I found my wallet after two days desperate searching, it was on top of a cupboard for some reason, the pendulum showed the right direction but not the height above ground, but I found it.

I believe plumbers sometimes use a stethoscope to listen for the hiss of running water.

Should I pop round.

[bankruatsteve]

Most cases when a PVC joint leaks there is a visible spray of water, especially when under pressure. It does seem likely to be somewhere in the water purification system. Re-check all system connections as those can weep almost undetectable to the eye but should be able to feel it. I also have had cases where poor quality shut-off valves have corroded so much that they will start leaking and one even broke right off. So, I would re-check all points of screw-in connection to the PVC.

[Artisi]

How long does it run for after coming on?

What type of pump is it?

How old is the pump?

Are you pumping from a tank or from the main system?

What makes you think it's the pump?

It could be a leaking valve in the pump not holding the pressure allowing it leak back to the low pressure side.

Is there a valve on the inlet side of the pump?

If yes, immediately the pump cycles and pressurises the system, close the valve on the inlet to the pump - if the leak is in the pipe the pump will want to switch back on as it losses pressure, if it's the pump it will stay pressurised.

If it's the pipe leaking I find it hard to believe you can't see any evidence of a leak - although you have said the water bill has esculated - but it is possible if leaking back to the m

[Artisi]

main

[lopburi3]

As said if using RO there is a lot of water going to ground when in operation - a normal system should be attached to a pressure tank and shut off but you have not advised what you have. What type of pump system? A check valve not closing pumping pressure water back into source is very common.

Normal search would be to turn off all taps that you can - bathroom should have shut offs (at least at toilet) to make sure it is not something local like the biggest fault (leaking toilet tank). Any hose in water pull out to make sure not leaking. Check all taps using paper to make sure no leak. In worst case you can usually plumb house using outside pipes so easy to see any faults and eliminate current system (cost is not that much and can be done neatly in many cases).

[wayned]

If your pumping from a tank, the tank is being filled from your main water line. The output of the pump feeds your house and it is normally "T"ed with the main water supply line so that you have both water from the pump and water from the main line, If the electric goes off you will still get water from the main line. There should be a flow control valve in the main line that will not allow the output of the pump to pump water back into the main line. If that valve has stuck open the pump will do as you described. I have very hard water and after failure of the valve 3 times I replaced it with a manual control. If the electric goes off I have no water until a manually turn the valve on.

[Lampang2]

Had the same problem.

Leakage under the house.

Had to put new tubes in and put them in the roof instead.

Never put polystyrene tubes in the ground.

Once building settles a bit, tubes Crack.

Use polyethylene if you absolutely must have tubes in ground.

[xpate]

Thanks everyone for the thoughtful replies, and yes stoneyboy, you can come try divining my leak if you are up to it, I am at wits end. I have tried getting my hands on a stethoscope as well, cooked, but to no avail. It seems I might have to go the replumb route, though I was hoping for an easier and more elegant solution.

Some additional information to rule out the scenarios envisioned by artisi, lopburi3, and wayned, the tank and pump system are stable when I shut off valve to house, so leak would appear to originate in house, please see pictures for further detail:

Water Purifier with Valve open pump off.

Valve to house closed (red stop cock on left side) and Pump on (pressure holds, pump is silent)

Indicates that pump system is functioning and not leaking prior entry to house system.

Only additional external pipe visible front of house:

So, pump and tank are ok, but no sign of leak inside or outside. (No geysers or floods, lol)

Is it possible that leak is back to main from the point of entry into house?

Once again, thank you all for your help..

I really need to solve this as the clock, errr meter is ticking

[lopburi3]

Do you have any water pressure in house with pump disconnected/valve turned off? If you do then you have a connection back to source from house (after that value from pump) somewhere.

[lopburi3]

Can not be sure of meter reading but is that really 45 PSI or something else? Expect that high a pressure on 20 year old plastic pipes is likely to be excessive for most joints (as Thai do not tend to push tight).

[xpate]

Yes mains is still connected to the house from street:

Down Left is original house main and running up and right is to the holding tank.

Yes, it says 45 psi, but not sure of accuracy, as that is from the RO tank.

But the system has been running like that since installation 5 years ago without incident.

Problem began with RO Tank and escalated over nine months. (I am work in Japan so not here that often, so I was unaware just how bad the situation had become.)

And I can't find leak anywhere in house, but I fear it is deep in structure.

Tank is installed well with intake from street then back to pump, then into house via the out side tap.

Thanks again

[RichCor]

Let's see if I have this right.

City/District community water 'service' (delivered at ~45psi)

In-Line chemical water treatment

SAN 1500 storage tank with refill float valve

Pump from storage tank

-> to residence

So two isolating systems. (Unless the storage tank is pressurized, not float-filled, and pump can be bypassed.)

If the 'pump' wasn't constantly running then I would assume a leak in the first system. But because the 'pump' is heard running without service being called (an open valve inside) then the leak is isolated to the second system, inside your residence.

Don't know why you can't see any evidence of a leak. Any weeds growing really really near the house?

Hopefully you find it before everything falls into the underground cavern being excavated.

[RichCor]

Wait, are you splitting the water service out, one side direct to the residence, the other to a storage tank (float-valve filled), then connected BACK into the residence???

Do you use a MANUAL valve control to prevent BACKFLOW??? I don't see any BACKFLOW / Anti-Siphon devices. Are you sure your not cycling the water in a circle (only running the pump, not actually using additional water through the meter)!!!

[lopburi3]

Looks as if there is a check valve (brass) after the coupling on the old route to house and that has failed and you are now pumping water back into your water tank when pump is running and you allow water into house on the route from tank/filter. You need to replace that check valve (or remove that path entirely and make a connection inside property and use an on/off tap that you can manually throw in case of power outage or pump failure rather than depend on check-valve (but that is up to you) - but for now am 90% sure that you have a check valve failure

[lopburi3]

One more check you can do is to keep that pump path closed and see if there is any change in your water meter reading - it should not increase but if there is a leak inside house it will.

[RichCor]

My assumption is that your system is acting as a reserve pressure tank for the community water system.

Missing numerous check-valves in your water lines, whenever the pressure drops, your storage tank and water pump are automatically cycling water on itself or backflowing water through your meter (it can run backwards), then the tank is refilling back to level when the pressure returns.

You need working check-valves somewhere on the both water lines after the split in the street.

[wpcoe]

If you end up replumbing the house, any place you have a branch off the main pipe, place a shutoff valve on the branch. That way if you have a leak in the future you can home in on the source much more easily by turning of branches.

Another trick is to place a few drops of food dye in each toilet tank to see if they are leaking into the bowl. Color in the bowl indicates a leak. It could be a combination of several slow leaks leading to the overall bigger water loss.

[Artisi]

Recycling at 7 second intervals would indicate a fairly major leak. Have you viewed the meter when the pump cycles - this will at least tell you if a major leak in terms of flow.

What pump is installed?

[xpate]

Thanks for your considered troubleshooting advise and suggestions.

Yes, I cannot find any sign of the leak and fear becoming a statistic under the heading "Gigantic Sinkhole Swallows xpate in CM" lol.

I turn off water to tank at tank shut off valve and meter keeps spinning

I last looked at this in April, and went through pretty much all of the troubleshooting advice given here, but I am very glad to have done it once more, to rule out anything.

Any further suggestions are always welcome and appreciated.

[lopburi3]

In that case (water off to tank but meter running) that direct link to house seems to be the source of water loss and appears you have a major leak under house someplace so believe it is time to redo at water lines. As said this can normally be done on outside and enter each service area with a shut off valve to help in any later issues.

[Artisi]

Putting my brain back into gear, as you are pumping from a tank it is very unlikely you will see any movement on the flow meter until the tank level drops after a number of cycles. Possibly you can monitor the tank level over a period of time / pump cycles.