Pipe leaking in basement but only sometimes

And it’s so little water we can’t tell when it leaks. Is there some type of sensor to tell us if it leaks?

Thank you

Like a water leak sensor?

(not in stock)

(In stock)

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I’m not sure, it’s soo little water it stains but never pools

There's enough water to pool, but it's spreading out. Make a little dam out of calking perhaps?

At $30 I'd say give it a try... perhaps when it's actively leaking there's a small rivulet. :slight_smile:


Maybe fix the leak instead?

Those sorts of problems can end up expanding into disasters if left unchecked.....


When my home was being built water was leaking from where they had sealed the pipe coming in to the house. They unsuccessfully tried sealing it from inside and ended up having to dig up the front yard to seal it from the exterior where the water was entering.

It happened to be all the right conditions for it to be caught early as it was a very abnormally wet spring and the water main a few doors down also was leaking. My neighbor had the unfortunate experience of their basement flooding just before closing on their home.

Best of luck! Hopefully you get to the root of it soon.

Maybe it's another poor assumption on my part, but I assumed that by identifying the moment when the leak is active, the Location can be deduced. Then the leak can be searched for in that area.

The thing is we got 3 estimates from 3 companies, all said something different and all want $6k plus. 1 said that pipe isn’t leaking, it’s just old stains, 1 says it is. One said it might only be leaking during hurricane type rain, which isn’t a big deal…

Sensative makes a leak sensor whose form factor may help... I bet if you placed it horizontally below the pipe it would pick up a leak.

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I would invest in a "damp meter" ... these are usually very accurate at detecting damp in floors & walls. Damp can persist for months even after any initial surface water has long gone. Compare the readings with the stained area and the non-stained area .... if they're the same or close then it's not leaking...

Could also go old school and put a sheet of "blotting" paper underneath the whole area. If that ever gets wet you'd see it even if the liquid had long since evaporated because it would leave behind a fresh stain deposit.


I used one of these to track down a water leak affecting my 2nd floor hall ceiling, specifically to determine whether I'd solved the problem before re-re-repainting. It was about $50 and well worth the investment. Not sure if my model works on something like concrete - this one looks specific to wood / plaster / drywall. But short money for a great tool.

(Leak turned out not to be the roof but rather a toilet on the 3rd floor!)

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I agree with the blotter paper, cheap and accurate.
I think the caulking dam idea is also good if you want to use a leak sensor.
Cheap ZigBee ones on AliExpress
Just search ZigBee leak sensor. About $10 each

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Put small sponge or small piece of paper towel on the ground with a leak sensor on top. Idea is these will absorb more water snd trip the sensor.


I would wrap some paper towels (folded to be 1 - 2 " wide) and tape them around the pipe in different areas. If it is leaking from the pipe the paper towels will tell you how far along the pipe the water entry is.

If not coming from the pipe then you know to look elsewhere.

If you have the feeling your neighbor's house was built the same time / same contractor. And you are planning on staying in your home for the foreseeable future, I would add a main water shutoff valve and a water sensor in the area the water pipe enters your home.

Curious, what is that white pipe you show in the photos? Too big for water, too small for sanitary drain.


There is a good chance that the leak is ground water coming in through the foundation rather than a leaking pipe, but it is difficult to be sure.

The problem with leaks like this are that they start small and always get worse. Over time leaking water will damage the concrete of both the foundation and the floor.

Sooner or later you will have to fix the problem. If you try to sell the house, the home inspector or new homeowner is certain to see the water stains on the floor and question a leak. Because repairing foundation leaks can be expensive, as you already know, a potential buyer will either cancel the sale or deduct large sums of money from the purchase price.

If the leak detector works, it will give you an idea when water is leaking. If it occurs when you are running the shower or draining the tub or clothes washer then the leak is likely to be piping related. If the leak only occurs after a rain storm, then it is groundwater intrusion.

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There is a tag hanging from the pipe. I wonder if it actually describes the purpose of the pipe? My guess would be a radon gas mitigation solution. Some sort of vent for under the foundation/slab? Just a guess! :wink:


So maybe that on the floor is Radon!
Just joking Radon is not a liquid (hopefully).

I suspect Radon Gas might turn to a liquid at a very low temperature…. :wink:

Apparently, the boiling point of Radon is minus 62 degrees C. The lowest temperature ever recorded in Antarctica is minus 90 degrees C, so Radon could exist as a liquid in those conditions.


I worked on devices for military aircraft. In a conversation with the aircraft mfg team I was told they had occasion to go through a "room" where because of a poorly insulated liquid O2 pipe, air was dripping off the pipe.


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