How to Check If Your Home Has a Hidden Leak





Introduction: How to Check If Your Home Has a Hidden Leak

There is nothing good about a water leak in your home! These steps will help you determine whether your home has a hidden leak that needs to be addressed.

Step 1: Has Your Water Usage Increased for No Apparent Reason?

If your water bill is showing an unexpected or inexplicable increase in water usage, it may be caused by an invisible leak. A leak is bad in so many ways: it causes unnecessary expense, it wastes precious water, and it could even cause damage to your home. Follow these steps to determine if there is a hidden water leak in your home.

Step 2: Find Your Water Meter

Your water meter is usually somewhere outside your home where the meter reader can easily access it on foot. Look for a concrete, metal or plastic cover in your driveway or front yard, or somewhere near the curb. In this example, the meter is under a concrete cover nestled between two bushes adjacent to the street. The meter cover may be stamped with the name of your local water provider, in this case East Bay Municipal Utility District (EBMUD).

Step 3: Open the Meter Cover

It can be tricky to open the meter cover with your bare hands, as meter readers usually have a tool to do it. In this case, we use a screwdriver through the hole in the cover to pull it open.

Step 4: View Your Water Meter

The water meter may be under a cap - open it. Inside you will see a gauge that may or may not be visibly moving. A tiny triangle (red in this example) moves more quickly and offers a finer gauge of motion.

Step 5: Turn Off All Water in Your Home and See If the Meter Moves

Turn off all water in your home, including sinks, dishwashers, washing machines. Do not use the toilet during this test period.

After you turn off all the water, set a toothpick on the meter at the exact location of the arm. This is an easy way to tell if the arm has moved after a period of time.

Wait at least 20 minutes to an hour, and then come back and view the meter.

If you see that the arm is now in a different position, that means YOU HAVE A LEAK and there is water somewhere escaping your system.

Step 6: Follow a Process of Elimination to Find the Leak

Now you will want to eliminate possible locations for the hidden leak. Start by shutting off the water for your entire home. Your water shutoff is typically located wherever a water pipe enters the home. It may be close to an outdoor faucet or hose.

Turn off the water to your house by turning the shut-off clockwise until it won't turn anymore. Then, repeat step 5.

If your meter continues moving during this test, you have determined that the leak is between the meter and the shut-off.

If your meter stops moving during this test, you will need to continue to search for the leak.

Step 7: Check Toilets

Toilets are a likely culprit as possible sources of hidden leaks, because they can run water directly into the sewer without you being aware of it.

Check to see if toilets are causing a leak by shutting off the water supply to your toilet(s) and repeating Step 5.

If your meter stops moving during this time, you've determined that the toilets are leaking!

If the meter continues moving during this test, you will need to continue to check elsewhere.

Step 8: Check Hoses, Under Sinks, and Under Hot Water Heater

If your home has additional shut-off valves that allow you to shut off portions of the home, use them to continue your process of elimination.

Here are some other common places to check for leaks:

  • Check outdoor hoses, and be sure that they are turned off at the faucet and not just at the hand-held valve. It's possible for hoses to lay in dirt or grass and drip water without the leak being visible.
  • Check under hot water heaters for a drip. These are important to catch early, as they can lead to a failure of the bottom of the hot water heater and a major water mess!
  • Check under sinks for puddles or drips.

Step 9: After Your Leak Is Resolved, Contact Your Water Provider

Some water districts offer to reduce your bills if you can show that you had a leak which was subsequently fixed. Once you have found and fixed the leak, contact your water provider to see if any relief is available.

Good luck and may the water gods smile upon your work!



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    23 Discussions

    By the way, that meter in the article was made in April 1993 as indicated by the date on the face of the register (04/93 or sometimes 0493). Also, many meters made before the year 2000 had serial numbers starting with the year of manufacture (they don't after that date). You do NOT want to request a new meter. That meter is aged and will be somewhat worn, and will likely be giving you a 3-8% discount by not measuring all the water used. A new meter will bring that back to within +/- 1.5%, the standard for new meters.

    As stated before, almost all meters have a leak indicator that moves with even he smallest flow. It is usually, but not always red as indicated in the photos below. It may be a triangle, star, wheel, or dial. sometimes it's in the middle of the sweep hand, sometimes off to the side. On digital meters, there will an icon or dot that is animated, flashing, or moving when water is flowing.


    what if the flow vavle's defective?

    Excellent instructable!

    Last month our water bill tripled over the previous month! I was worried we had some kind of crazy leak somewhere that would cost $$$$ to fix. But I went through steps very like those here, and found the problem was from a toilet. It had malfunctioned enough that the tank was over-full. It was high enough that the water was running straight into the overflow pipe. Cost me $13 for a flush mechanism replacement (I did it myself.)

    I actually found that when I did the "put food color in the tank and see if it shows up in the bowl" test. (That tests if the flapper at the bottom of the tank is leaking.) I didn't see much color at all in the bowl, but while I had the top of the tank off, I could see the water running into the overflow pipe. It was very quiet, which explains why I hadn't heard it previously. O.o

    I'm still watching/recording the meter readings just to make sure we don't have any more SURPRISE! giant water bills.

    1 reply

    So glad you caught the leak! Have you contacted the water company to see if they can discount the high water bill? I was able to get ours reduced slightly due to it being a leak.


    I'm an ex-UK water utility engineer with an interest in water consumption.

    I collect rainwater avidly, wash in it, never use utility water in the garden except for the increasing number of droughts when all the rainwater has gone. The only thing I don't do with rain water is drink it. The great thing about rainwater is that it is soft water - it protects your above and below ground pipes from scaling.

    Leaks on the customer side of a meter can cost you thousands of UK Pounds or Dollars, and that's just the bill. Add in the ground erosion and double the bill for wastewater treatment and a neglected dribble will hit you in the pocket.

    I have read the water meter every month for the last twenty years, specifically to pick up unusual patterns. I'm working on an Arduino based "smart meter" to give me real time consumption data. The local utility is fitting Smart water meters, but this is just to let them cut down on manual meter reading - it does nothing to help you.

    Good practice says that now and again you should close valves on your side of the meter and check that there is no movement on the finest digit - the meter shown in the image is old (1993) and should not be in use in 2015 - it's outside it's calibration date. A cubic foot of water is 6.2 gallons, roughly 28-litres. The white on black digits are tenths and hundreths of a cubic foot, i.e. 2.8 and 0.28 litres. One rotation of your red needle is 280-ml, and this can be read to 1/100 of a full rotation, i.e. 2.8-ml. With all downstream valves closed, this should not move in 24-hrs, or even a month - if I lost 2.8-ml in one day, that says leak.

    With "Smart" meters, people are less likely to read meters themselves and this is bad news. Having seen contractors installing new meters, errors are built-in. The electronic reading increases but the mechanical reading does not or vice-versa.

    I have knowledge of consumers getting bills of >£5000 for 6-months, and cases of utility sites neglecting obvious leaks and charging themselves thousands.

    With the move from "warning" or overflow pipes to overflows in WC cisterns, this is one example where leaks go undetected. I now fit electrodes in all inaccesible water places ( under tanks in the roofspace for example) and measure the resistance/conductivity to detect leaks.

    We have a duty to conserve and not waste precious, highly purified and treated potable water and your "Indy" highlights it nicely.

    For those on domestic meters (UK), your wastewater bill is based on 92% of your water consumption, so 1-litre of water used through the meter, is 0.92-litres of wastewater on top. Business customers e.g. soft drink manufacturers, can argue that most of the water used goes into the product and get the 92% figure reduced, but domestics can't.

    The message? Read the meter regularly, close the valves off, and fix the downstream leaks.

    1 reply

    Thank you for this thorough comment! Interesting that the meter is old, circa 1993. The photo is from 2015 and this is a typical meter for our area (San Francisco Bay Area, California).

    Well done. I use a similar method for finding the big vampires of power. This only applies to an annolog meter.

    you click the "vieuw all steps" button under the first step. After you did that you will see that everything is explained in this instructable.

    Great tips for troubleshooting!!

    Here's another I've found to save a few dollars..

    In many locations your sewer bill is based upon your water usage..

    SO..if you water the lawn, fill a pool, wash the car, wash down the deck etc.. your sewer bill is going up..

    If you press the issue enough the water company will have to install a second meter for your outside usage..

    SO.. if you use a lot of outside water.. this little tidbit can save ya some bux on your sewer bill.

    This works great with standard meters.

    I once lived in a city where all of the water meters were "Odometer" type meters with no arrow or spinning triangle.

    After watching this city employees trying to figure out why my water bills were 1/2 of "NORMAL" I watched this meter and recorded it every day for 2 months.

    The funny thing about it was the tenths and Unit wheels worked great so every time they filled a five gallon pail to check useage it showed normal.

    But the TENS would only turn about every other time that the unit dial turned.

    great for me bad for the city.

    greaт joв poѕтιng тнιѕ тryed and тrυe ιnѕтrυcтaвle! ι нave υѕed thíѕ wαtєr ѕαvíng tríck coυnтleѕѕ тιмeѕ тнroυgнoυт мy чєαrѕ αѕ α σwnєr σf α σldєr hσmє. íf чσu lívє ín єαrthquαkє prσnє αrєαѕ ít'ѕ αlwαчѕ gσσd tσ chєck αftєr α gσσd ѕhαkєr!

    As far as I know all water meters have that little triangle or a star or gear shaped piece in them. You can also tell if you have a leak with that because any time water is running it will spin at a very noticeable speed. You can actually test this by turning off all water and seeing that it's stopped and then simulate a leak by running water from something in the house.

    This is great advice. I recently had a 37,000 gallon leak that quintupled my water bill... Had to walk the back yard to find the swamp!

    Great instructable. Also I don't know if all water meters are like this I know the ones in my town are, and yours looks like it. But that little red triangle should be a tattle tale that will spin faster than the large dial and it is easier to tell if water is flowing through the meter, because you can just watch it for a bit. Or at least that is how we determine if there is a water leak at someones house in our town.

    You've provided very valuable information in this comprehensively composed article. Thank you for sharing your knowledge. Welcome to the community.

    Very nice. Thanks Purrrgirl.

    This is a great instructable. Such important and useful information. My friends just dealt with this problem in a new home they moved into. Luckily, the city took care of it add the problem was where their house connected with the main line.