Any businesses in Chiang Mai to check for underground leak in a single family residence? I know in the US they have/use the technology for this. I'm guessing no way in Thailand, but doesn't hurt to ask.

Many Thai plumbers can do it by attaching a pressure gauge and closing all the valves, pressurize the system, wait, if pressure does not drop, no leak. It is standard procedure here on new construction (good quality new construction). All that is needed is a pressure gauge and a small hand pump with fittings to pressurize the system, if the water pressure is not high enough when the valves are closed.

If your house water comes from a dedicated pump with a pressure tank, turn off all the valves and listen for a few hours to hear if the pump cycles on, if so you have a leak, if it is a big leak the pump will cycle on quicker and more frequently.

But its not always a leak that sets off your pump re filling the storage tank.

In this weather evaporation can activate the pump for 5seconds several times a day.

Any leak before the meter though is no cause for concern

Before getting into this further it would help if the OP described his water system.

Is it city water with no pump?

Is it water coming from his elevated storage tank into the house?

Is it water coming from a pump into the house?

Or something else?

Also, why is it that he/she wants to check for leaks? Is there some indication that there may be leaks?

Okay, here's more info. I have a tank and water pump. And I know there is a leak because the pump comes on for about 2-3 seconds every 8 minutes. And the pump presure switch is not adjustable. It's really annoying. So, I know I have a leak, one story house, and I want to pinpoint the leak before I start tearing up the concrete all over the place.

Any sophisticated leak detectors out there?

If you have got a pressure vessel, check the air pressure.

Okay, here's more info. I have a tank and water pump. And I know there is a leak because the pump comes on for about 2-3 seconds every 8 minutes. And the pump presure switch is not adjustable. It's really annoying. So, I know I have a leak, one story house, and I want to pinpoint the leak before I start tearing up the concrete all over the place.

Any sophisticated leak detectors out there?

2 questions..you have a tank. Is is a pressure tank or just a water tank. A pressure tank has an air chamber and is designed to hold water under pressure (by the air pressure) and holds anywhere from 4-100 gallons according to system design.

Second, do you have any shock busters (Arresters) installed on your water lines at a toilet or where there is a faucet with a long run? These are to prevent water hammer and blown (or leaking lines)

Otherwise, do you have any shut-off valves on your likes? This same problem can be caused by a leaking toilet valve, etc and without a large pressure tank, the pump will run very often.

Okay, here's more info. I have a tank and water pump. And I know there is a leak because the pump comes on for about 2-3 seconds every 8 minutes. And the pump presure switch is not adjustable. It's really annoying. So, I know I have a leak, one story house, and I want to pinpoint the leak before I start tearing up the concrete all over the place.

Any sophisticated leak detectors out there?

Does the pump move water into the tank or out of the tank and into the house?

A properly function pressure switch would indicate a leak if the pump is cycling as you say but if the switch is not functioning properly it could cycle as you say and just be a bad switch not indicating a leak (I had one like that).

Probably no "sophisticated leak detectors" and that is why people are suggesting other alternatives.

Thanks all for the replies. The pump moves the water from the tank. It's a new pump and I checked the presure switch, there is no way to adjust it. And I do know there is a leak, maybe two. Why, because I found one already from the shower valve, the fitting in the wall was not glued. So, now the pump is coming on less frequently and probably another leak that I cannot locate. I was lucky finding the problem from the shower because it was on an outside wall, the others are not. So, that's why I need the technology to locate the other leak, other than busting up tile and concrete all over the place.

You might want to install a one way check valve just after the pump.

When the pressure switch shuts off the pump, the housing is under pressure also, and there is nothing to stop the water under pressure from reverse flowing back into the tank if there is a pressure differential.

I had a water tank in my house in Canada, just before the pump, and had to install the check valve to stop back-flow.

Well, you are part way home with low tech so keep looking for other leaks. Outside faucets connected to the water system? Very slowly running toilets? Leaks will often show themselves with time, I had to wait 10 days before one leaked enough to show.

If the problem started with the installation of the new pump, that could be the cause. Hitachi pumps and perhaps others require the installation of an included but not installed spring when being used to pump from shallow or raised tanks rather than from wells. So check your installation manual.

We spotted one leak, when the paint on the outside-wall started bubbling, and later the terrace got a bit damp.

That's the trouble with burying pipes inside walls.