testing for broken water main - InspectionNews

John Dirks Jr · #1 (**permalink**) 11-05-2009, 07:22 PM

Consider the house water supply as public and therefore it would have chlorine in it.

If the water supply main, or even the main drain under the foundation were leaking, could you expect the possibility of the chlorinated water getting into the sump pit?

If so, can a conclusion be made by testing the water in the sump pit for chlorine content?

What would the cheapest test method be?

Gunnar Alquist · #2 (**permalink**) 11-05-2009, 08:01 PM

Quote:

Originally Posted by John Dirks Jr

Consider the house water supply as public and therefore it would have chlorine in it. If the water supply main, or even the main drain under the foundation were leaking, could you expect the possibility of the chlorinated water getting into the sump pit? If so, can a conclusion be made by testing the water in the sump pit for chlorine content? What would the cheapest test method be?

John,

Seems reasonable. Water in the sump could also be tested for fecal matter as well. I wonder if a pool test would register the small amount of chlorine found in municipal water supplies.

However, it seems to me the cheapest way to determine if there is a leak is to look at the water meter while all of the faucets in the house are off. I don't know where the meters are located in the land of Mary, but over here on the left coast, we generally have our water meters underground between the sidewalk and the street curb. If I am concerned about a main water leak, I will turn off the main at the house and watch the meter for movement. If the meter is located in a basement, then obviously this will not work.

Jerry Peck · #3 (**permalink**) 11-05-2009, 08:11 PM

Quote:

Originally Posted by John Dirks Jr

could you expect the possibility of the chlorinated water getting into the sump pit?

"possibly" is the key word there.

Quote:

If so, can a conclusion be made by testing the water in the sump pit for chlorine content?

I would not rely on a negative test as being negative, nor rely on a positive test being positive, of a leak.

Quote:

What would the cheapest test method be?

Hire a plumber to do a pressure hydrostatic test to 80 psi minimum, if it holds pressure ... it is not leaking.

Mike Picarello · #4 (**permalink**) 11-06-2009, 04:47 AM

I have done just what Gunnar has suggested and it works. Jerry's suggestion will work as well but there will obviously be plumber costs involved.

Thomas Barker · #5 (**permalink**) 11-06-2009, 06:24 AM

I can't believe the answers I'm reading. Test for chlorine in a sump pit? Hire a plumber to do a pressure test? Why complicate things? Gunner nailed it!
To check to see if you have a hidden leak first shut down everything in the house, no flush, no drinks of water, and if you are on a meter go out and check the little pointer in the gage. It should not move or creep. if it does you have a leak. If you're on a pump then check the pressure gage after the pump builds up to pressure and shuts off. The gage should not fall and the pump come back on. If so then you have a leak.
That's how we do it in the Tampa Bay Area. Regards to all, Tom

Tom Rees · #6 (**permalink**) 11-06-2009, 07:13 AM

I test at the meter like Gunnar suggested, most meters have a low flow meter separate from the main counter. In this area most of the time the leak is at the stop and waste valve for the sprinkler system so it is hard to tell if it is the main line or valve that is leaking. I routinely do this test when I find a galvanized steel service line.

Scott Patterson · #7 (**permalink**) 11-06-2009, 07:42 AM

If you see water that is moving then the test for chlorine might work. Chlorine is a gas that is held in suspension in water with of all things Ammonia. This why you see anhydrous ammonia tanks at water treatment plants... Once chlorinated water leaves the pipe the chlorine starts to dissipate.

I have taken water samples from water seeping out from under the foundation of a home before to see if it was from an underground spring or the city water. I just told the lab that I wanted to know if the sample was city water or spring water. I think it cost around $30 at a local analytical lab.

H.G. Watson, Sr. · #8 (**permalink**) 11-06-2009, 09:16 AM

I'm confused. Are you asking about a suspected leak before the meter or after the meter?

Randy Aldering · #9 (**permalink**) 11-06-2009, 06:28 PM

The meter's intrinsic leak detection will not work for leaks between the main and the meter. The only way to determine a leak between the main tap and the curb box is to dig it up. Testing for loss of pressure between the curb box and meter can be accomplished, if it can be ascertained that the curb box valve is competent (working, not leaking). The water and sewer bill will usually not betray a leak between the main tap and the meter. Look for dampness around the main supply penetration of the foundation wall or slab, and look for unusual low spots in the yard where the supply connection traverses the lot.

Matthew Barnicle · #10 (**permalink**) 11-06-2009, 07:45 PM

This might sound strange, but you can sometimes hear a leak if you put your ear against the pipe. If it is big enough to show up in a sump pit, it might be big enough to hear it. Clearly, the drip/leak detector on the meter would be best, but sometimes those are non-existant or on the house side of the leak in question. Another idea, although this would probably break some rules...if you are able to turn the water off at the street... backfeed from your neighbors supply through the outdoor spigot and a garden hose with two female fittings, and see if his meter turns. Or, simply see if your system de-pressurizes by waiting an hour and opening up a faucet on the top floor. If there is no leak, it should still initially come out with pressure for a second. Also, I don't know how long it takes for groundwater to make it's way to the drain tile, but you might want to try counting the number of times the sump kicks on in an hour, then turn off the water at the street and wait a few hours and count it again.

Jerry Peck · #11 (**permalink**) 11-06-2009, 08:15 PM

Quote:

Originally Posted by Mike Picarello

I have done just what Gunnar has suggested and it works. Jerry's suggestion will work as well but there will obviously be plumber costs involved.

I can tell you from first hand experience that it is cheaper to pay the plumber and find the leak.

I had an intermittent water leak, I could see it by watching the flow indicator on the water meter ... when it was leaking, but most of the time there was no leak and thus no leak flow indication on the water meter.

That intermittent leak in the water service pipe went on for about 3-4 months before I was able to locate the leak and repair the pipe, at usage of about an additional 15,000 gallons of water over that time period of trying to find the leak, which meant that I was only able to try to find the leak when it was actually leaking and moving the flow indicator.

Had I had a plumber do a pressure test, the line would not have held pressure, and it would likely have created a little geyser where it was broken and leaking.

I would use the flow indication to *show a leak* but would never rely on that flow indicator to *show it was not leaking*, that would be a big mistake, and could end up being very costly for you as a home inspector.

Pressure testing the piping is the best and surest way to check for a leak.