How to Find a Water Leak in Your House

Ways to quickly and easily locate water leaks all around your home

Co-authored by David Balkan

Last Updated: March 9, 2023 References

In most cases the water line running to your home is "metered" for accountability and billing purposes. A leak on your line can be very costly. Yet, even a very small leak can be found through trying a few simple techniques and can save you from a nasty surprise from your local utility company. If you have been notified that you have a leak, here are a few steps you can do before calling a plumber. The more you do, the less it will cost you in the long run!

Method 1

Method 1 of 6:

Hot Water Tanks

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Check the Pressure Relief Valve on the hot water tank. Sometimes these valves are plumbed directly into a drain and may be leaking without your knowledge. If you can't remove the drain pipe to check for a leak listen for a hissing sound, it may be leaking.^{[1]
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Research source}

Method 2

Method 2 of 6:

Toilets

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Check the toilet for leaks by removing the top off the tank and listening very closely. If you hear any hissing at all, try to locate where it is coming from.^{[2]
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Research source} If you locate the area where the leak is coming from, assess it and determine if you can fix it. If you can't, then call a plumber.^{[3]
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Expert Source

David Balkan
Professional Plumber & CEO of Balkan Sewer & Water Main
Expert Interview. 29 April 2021.}
- If nothing is noticeable, add some food coloring and put a couple of drops in the tank (not the bowl). Wait several minutes and if you have coloring in the bowl, you have a leak in the flapper at the bottom of the tank that is allowing water to seep through.^{[4]
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  Research source} At this point you can assess if you want to do the repair yourself, or call a plumber.
- If you have more toilets, go ahead and repeat the process with each toilet to make sure you don't have more than one problem.

Method 3

Method 3 of 6:

Meter Line

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If the toilets are fine, check the line running from the meter to the house.^{[5]
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Research source} While this may sound difficult, you can save money if you can locate the leak for the plumber.
- If you know you have a shut-off valve by the house, shut it off temporarily and check the meter by removing the lid and watching the dial on top of the meter.^{[6]
  X
  Expert Source
  
  David Balkan
  Professional Plumber & CEO of Balkan Sewer & Water Main
  Expert Interview. 29 April 2021.}
- If you can't see the meter head, try digging around because they sometimes have dirt or grass covering the top of them. Once you locate it and the valve is turned off by the house, watch the meter to see if is turning. If it is still turning, then the leak is between the meter and the house. That is, unless you have a leaking valve, and this very common with these older bronze gate valves. Then, your leak may also be inside the house.
- At this point, walk the area between the meter and the shut-off valve. Look for signs of a leak such as: soft muddy areas, grass that is greener than the rest or growing much faster than other areas. If you see such an obvious sign, call the plumber or assess if you can make a repair yourself.
- If you have the valve shut off at the house and the meter has stopped moving, then the leak is somewhere in the house. Try some other techniques to try to locate the problem.

Method 4

Method 4 of 6:

Hose Bibs

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Try to locate a leak by the house. This will require you to locate all the hose-bibs (hose-bibs are the pipes that you hook your hoses to, in case you were unsure!). Usually an average residence has one hose-bib in the front and one in the back, but be sure to find every one that you have and listen carefully.^{[7]
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- Once you have located them, take a screwdriver, preferably one long enough to give yourself room to work, and put the metal tip of the screwdriver directly on the metal part of the hose-bib. Put your thumb knuckle on the top of the screwdriver, and then place your knuckle on the side of your head, immediately in front of your ear. The sound will travel directly to your eardrum. The idea, here, is for the solid screwdriver to work like a stethoscope. This works for most metal valves, as well.
- Listen carefully for any sound emitting from the hose-bib. If you hear anything at all, remember where it is (perhaps mark it with chalk), and go to the next one. If the sound emitted gets louder at any of the other hose-bibs, then the leak is closer to that particular unit. Note that and contact your plumber: Giving the plumber this information will save the plumber loads of time in finding the leak, which in turn saves you money.
- If you survey all the hose-bibs and still find no sound, go into the house and follow the same process with the screwdriver on your house fittings such as faucets in sinks, shower valves, washer, hot water heater (be careful to avoid being scalded when working around the hot water heater). If you are still not sure, just contact the plumber.

Method 5

Method 5 of 6:

Other Leaks

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Check the garden.^{[8]
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Trustworthy Source
United States Environmental Protection Agency
Independent U.S. government agency responsible for promoting safe environmental practices
Go to source} Look at hoses, taps, and drip irrigation systems.
2
Check the shower head for leaks.^{[9]
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Trustworthy Source
United States Environmental Protection Agency
Independent U.S. government agency responsible for promoting safe environmental practices
Go to source} It should be a fairly straightforward home repair if this is a source of leaking.^{[10]
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If you have a swimming pool, it is important to check to see if it has any leaks.^{[11]
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Method 6

Method 6 of 6:

Near Enough is Helpful

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Recognize that in many cases a leak can be very hard to locate. Not all of the leaks outlined in this article can be located and if you're not used to plumbing positioning, you may miss something easily. All the same, if you try these steps, you should be able to find an approximate location and this is a most valuable exercise in itself because it will help the plumber (many plumbers do not like searching for a problem so anything you can do they will appreciate), making it time saving for the plumber and that translates into savings for you.^{[12]
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Expert Source

David Balkan
Professional Plumber & CEO of Balkan Sewer & Water Main
Expert Interview. 29 April 2021.}

Expert Q&A

Question

How do you detect a water leak under concrete?

David Balkan
Professional Plumber & CEO of Balkan Sewer & Water Main
David Balkan is a Professional Plumber, CEO of Balkan Sewer and Water Main Service, and President of Balkan Sewer and Drain Cleaning. As a hands-on owner of these companies for over 40 years, David is knowledgeable about water service lines, sewers, and drain line issues. David is a Committee Chairman of the Master Plumbers Council and has sat on the Executive Committee of the Sub Surface Plumbers Association of New York for over 30 years. His knowledge and solution-oriented approach contributed to Balkan Sewer and Water Main Service being the largest and most trusted service in New York City and the recipient of the 2017 Angie’s List Super Service Award.

David Balkan

Professional Plumber & CEO of Balkan Sewer & Water Main

Expert Answer

That is probably one of the most difficult leaks to detect. Every meter has what's called a leak dial. If your meter is spinning and there's nothing being used in the house, then you either have a running toilet or you have a leak under the slab. Determining where that leak is exactly can be tricky, and I recommend calling a professional for help.
Question

The city says I have a leak. I called a plumber and he couldn't find a leak. I shut off all the valves inside and out, there's no water damage in the house. Where could it be?

Community Answer

It sounds like the line between the meter and the main shutoff valve.
Question

The city says I have a leak. I can hear water running in one wall of house but there is no evidence of a leak, what could be the problem?

Community Answer

It's probably the main cold water supply or the branch of supply that has the leak. If you have that volume of water running through your pipes, it's underground, under the slab or flooring. Turn off your shutoff at the water heater to determine if it's on the hot or cold. If it's on the hot, walk around with a laser thermometer to try and find the source of leak. To pin point cold water unfortunately, you need a listening device.

Warnings

If you suspect the offending leak may be in the water heater, call an expert. Don't stick a screwdriver in there. You may cross wires or puncture the tank.

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If you plan on fixing a leak in your toilets yourself ask what the age of the house is before you work? You might discover that fixing one leak causes another one or five because of old gaskets, washers and rubber?

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Never dig without the proper locate as it very dangerous and can cause you physical harm, as well as financial. If you are not sure, always call the expert, your local plumber!

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Very important! If you do find the leak and decide to Try to dig it up please make sure you call your other utilities and ask them to mark their utilities on the property! Most states in the U.S. have a utility locate center just for this purpose.

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Things You'll Need

Screwdriver
Repair tools and items (optional)
Internet or Yellow Pages to find a plumber - it's helpful to ask other people who they trust as plumbers, along with checking online sites that allow consumers to rate tradespeople