How to Find a Leak in the Plumbing of Your Home

I recently had my septic tank pumped out and noticed a steady stream of water coming from the house drain pipe into the tank. Where could it be coming from?
-Betty

Hi Betty,
The most likely culprit is a leaking toilet, but there are a couple of other possibilities to consider as well:

Start by inspecting the plumbing fixtures in your home—such as sinks, showers, and tubs—to be sure water from a faucet isn’t literally going down the drain.

Next, check to see if your toilet might be leaking by closing the cut-off valve and flushing it. Give it 5-10 minutes to fully drain, then check the pipe into the septic tank to see if the water has stopped flowing. If it has, the problem is with that toilet. If it’s still running, try the same procedure with any other toilets. If you find that the problem is with one or more of your toilets, check out our article on How to Repair a Toilet to see how to go about fixing it.

If the mystery leak still isn’t solved, check to see if there are any other sources of drain water you haven’t considered. Some that come to mind include a basement drain, the drain line from an air conditioner unit or hot water heater pressure relief valve, the drain from the pan under a water heater or washing machine, and the backflow from a whole house water filter. While most of these are usually plumbed to drain outside on the ground, it’s possible they were tied into your house plumbing drain system.

Another way to check to see if the water is coming from the plumbing inside your house is by monitoring your water meter over a few hours when nothing is running (be sure to turn your ice maker off!). If there aren’t any leaks or water flowing from your supply lines into the drain, the dials on the water meter won’t move.

Good luck,

Danny

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7 Comments on “How to Find a Leak in the Plumbing of Your Home”

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Ronnie Yow Says:
March 14th, 2010 at 6:47 pm

I have the same problem i truned off all water to the house at the whole house water filter also im on a well.No water going to house but still have small leak. It did get less flow when water turned off,im thinking water was just sitting in pipe.But when turned water back on water stream got bigger again. Im lost at whats leaking.
yemane abraham Says:
July 30th, 2010 at 6:53 am

I have abroblem in the house water leak Icheck toilet not . when turn on water meter runing fast but Ican hear nothing water leak .Iam lost at whats leak.
Sharon Nelson Says:
November 22nd, 2010 at 8:57 am

My son got a $450.00 water bill. He call the water co. thst cam out and said it is not on the city sideand left. You can not hear a leak the ground isn’t wet. How can you check
for leak unground. Thank you very much
Sharon
Ben Erickson Says:
November 22nd, 2010 at 11:15 am

Hi Sharon,
The best way to check is by monitoring your water meter when you’re not using any water in the house. Click on the “monitoring your water meter” link in the article above to see how to go about it. Also, most cities will give you a one-time credit on your water bill if you can demonstrate to them that the high bill was caused by a leak. At the very least, they should credit you for the sewage part of the bill if the water that was leaking wasn’t running into your drain line.
Kevin Laborde Says:
April 6th, 2011 at 9:11 am

I have a shut off valve to is connected to my water filtration system. During a servicing of my ice maker I had to turn the valve off and on several times. Now I see a slow dripping from the valve. What is the best way or easiest way to stop the leak?
Tadeusz Komosa Says:
July 21st, 2011 at 12:55 am

No hot water tap is open but the instant hot water goes on which means the hot water must be leaking somewhere in large quantity.
How can I find this leak?
ron jones Says:
September 7th, 2011 at 11:01 pm

We have would looks like a water stain at the top of our house in the far corner, but more like an oil stain. It’s 110 degrees here and its not only at the top but about sixteen ft down there is a small stain at the top and on the bottom of the window that looks like the same. I had a plumber come out and he did a water test and checked the meter and said its not water leak or mold. I am not sure if this is possible but about 4 months ago we had a beehive removed next to that same area and they had to spray something up there. Could it be dried honey melting down or between the stucco? we have not ran our AC in over three years since adding a whole house fan in the attic. also the wall near the window is not sticky.

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