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tberg

join:2001-08-23
Greenville, SC

Water leak under slab

I noticed that my water bill jumped the last two months and I'm not watering the garden anymore. I did a little checking and found that if I turned off the valve to the water heater, the water meter stopped turning.
So, that means I have a water leak in my hot water lines. The problem is that my house is on slab. I'm losing about 1500 gallons per month or 50 gallons per day. That's one water heater full per day.
How do you go about finding and fixing a problem like this without taking a jack hammer to the whole house? Are there detection devices that can get you within a few feet?
I see no signs of water leakage from "above".
Thanks in advance for any tips. Of course, as a DIYer, I don't want to call the pros unless I really have to.


Zach1
Premium
join:2006-11-26
NW Minnesota

First thought would be to walk around the house in bare feet. If you are loosing 50 gallons of hot water a day, there is a good chance the floor will be warmer in the area close to the leak. Fixing the leak will probably require a jackhammer or rerunning in the attic. Not likely to be a simple, easy fix.
--
Zach


garys_2k
Premium
join:2004-05-07
Farmington, MI
reply to tberg

Personally, I'd abandon the leaky pipe and run a new one above the slab, even if it meant a drywall soffit here or there. If the pipe has started to leak at one point it's quite likely the whole thing is nearly rotted out.



John97
Over The Hills And Far Away
Premium
join:2000-11-14
Spring Hill, FL
kudos:1
Reviews:
·Bright House
·ooma
reply to tberg

Is your T&P valve piped into a drain or anything? Maybe it's something as simple as that.

If not, and it's a pipe lieak I think garys_2k is right on the mark.
--
So put me on a highway, and show me a sign.
And take it to the limit one more time...



Raphion

join:2000-10-14
Samsara
reply to tberg

In my current house, the cold water pipes started leaking under the slab long long ago. We simply abandoned them in-place, and ran new pipe for both hot and cold through the attic.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to tberg

Find someone with a FLIR (infrared) camera. Some of the home inspectors have them as well as some of the energy conservation testing companies. The camera with an experienced operator can detect moisture.

Haven't found a place to rent one in my area but they do rent them some places. The camera sells for over $6000 so you probably don't want to just go out and buy one!



mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to tberg

Eliminate the T & P valve 1st.

Find where it drains. Mine was buried about an inch in dirt and mulch.



leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
kudos:10
Reviews:
·SONIC.NET
reply to tberg

At that flow rate you may also be able to follow the route of the leaking pipe acoustically.

As for the thermal imaging (probably the best way given that it is hot water that is leaking), some utility companies have a free service that performs a home energy efficiency audit. Some of those energy audits include thermal imaging of your home.
--
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Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
reply to Raphion

said by Raphion:

In my current house, the cold water pipes started leaking under the slab long long ago. We simply abandoned them in-place, and ran new pipe for both hot and cold through the attic.

It gets down to "0" at times here. Not a very viable idea.


Raphion

join:2000-10-14
Samsara
Reviews:
·Verizon FiOS
reply to robbin

said by robbin:

Find someone with a FLIR (infrared) camera. Some of the home inspectors have them as well as some of the energy conservation testing companies. The camera with an experienced operator can detect moisture.

Haven't found a place to rent one in my area but they do rent them some places. The camera sells for over $6000 so you probably don't want to just go out and buy one!

I would LOVE to go out and buy one of those cameras. So much fun, and so many uses... but I still just can't justify the price of a reasonably good one.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to leibold

said by leibold:

As for the thermal imaging (probably the best way given that it is hot water that is leaking)

The interesting part is that it doesn't matter if it is hot water or not. FLIR cameras appear to be great for moisture detection of any kind.

»lmgtfy.com/?q=FLIR+moisture+detection


leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
kudos:10
Reviews:
·SONIC.NET
reply to Raphion

said by Raphion:

I would LOVE to go out and buy one of those cameras. So much fun, and so many uses... but I still just can't justify the price of a reasonably good one.

I got the opportunity to use one during emergency preparedness training and they told us prices have come down significantly as more and more fire departments are buying them (still about $4000 if you want all the extra features for firefighters). We used it to locate people in a smoke filled room and it was pretty amazing (due to the smoke there was zero visibility with flashlights).
--
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GadgetsRme
RIP lilhurricane
Premium
join:2002-01-30
Canon City, CO
reply to Jack_in_VA

said by Jack_in_VA:

said by Raphion:

In my current house, the cold water pipes started leaking under the slab long long ago. We simply abandoned them in-place, and ran new pipe for both hot and cold through the attic.

It gets down to "0" at times here. Not a very viable idea.

Actually quite viable if done right. Our master bath pipes are in the ceiling and the low so far this winter has been -5F. The pipes are in foam insulation, right on top of the rafters, and buried in R60 insulation. We haven't had them freeze in the 5 winters we been here. The lowest temp has been around -20F.
--
Gadgets


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom

said by GadgetsRme:

said by Jack_in_VA:

said by Raphion:

In my current house, the cold water pipes started leaking under the slab long long ago. We simply abandoned them in-place, and ran new pipe for both hot and cold through the attic.

It gets down to "0" at times here. Not a very viable idea.

Actually quite viable if done right. Our master bath pipes are in the ceiling and the low so far this winter has been -5F. The pipes are in foam insulation, right on top of the rafters, and buried in R60 insulation. We haven't had them freeze in the 5 winters we been here. The lowest temp has been around -20F.

Could it be enough heat rises through the ceiling to keep the pipes above freezing? How about if the power is off and no heat is present? They would have to equalize to the ambient temperature regardless of insulation level.

I don't think I would take that chance

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

Sometimes there is no option. If the lines are bad under the slab, depending on the floor plan, jack hammering isn't necessarily the best answer. If the power goes out (with no heat for an extended time) well insulated pipes in the attic aren't really any different than pipes in a two story house. Either the house needs to be maintained at some heat level above freezing or the system MUST be drained.



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom

said by robbin:

Sometimes there is no option. If the lines are bad under the slab, depending on the floor plan, jack hammering isn't necessarily the best answer. If the power goes out (with no heat for an extended time) well insulated pipes in the attic aren't really any different than pipes in a two story house. Either the house needs to be maintained at some heat level above freezing or the system MUST be drained.

Agree Robbin. That's something that can happen and I know I'm on a slab but not going to take that chance. I have emergency propane heat for minimum use but not enough to prevent that.


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
reply to tberg

You might be able to see it with a good heat gun. Just a thought.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

Could you expand on that? Are you talking about a contractor's heat gun (industrial hair dryer/melter)? Or are you referring to the FLIR camera I previously recommended? Just trying to understand -- I have a heat gun out in the van, but can't figure out how to see anything with it.

[edit] Had to look this up as I wasn't positive of the words behind the acronym -- FLIR - Forward Looking Infrared Radiometer



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom

I completly screwed up the description. I meant:

infarared heat indicator hand held. Point and read temp.

There are a lot of hand held ones ranging from cheap to very good. I was thinking op may could find one or borrow one sensitive enough to see a temperature difference. Just a thought.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

Ok -- so you are thinking it may be possible to see a temp difference with a handheld IR thermometer. Be worth playing with if a person had or could borrow one. Doubt it would be worth the gamble if had to buy it. Good thought, though. I'd try it if I had one.

Actually the OP didn't describe their house. I have, in the past, used a cheap moisture detector on slab, tile joints as well as a hardwood floor to find a leak in a wall. It's amazing how what looks pretty much the same with the eye can have 10 to 20% difference in moisture content. Paid about $35 for mine at Lowes. Could possibly get you within 5 feet or less from my experience.



GadgetsRme
RIP lilhurricane
Premium
join:2002-01-30
Canon City, CO

1 edit
reply to Jack_in_VA

said by Jack_in_VA:

Could it be enough heat rises through the ceiling to keep the pipes above freezing? How about if the power is off and no heat is present? They would have to equalize to the ambient temperature regardless of insulation level.

I don't think I would take that chance

That one is easy.
1. Shut off water to house.
2. Open all valves in the master bath.
3. Open all valves in the front bath and kitchen and leave open until water quits running.
4. Close main valves to master bath, which are in the crawl space.
5. If it looks to be an extended time with out power leave it like this.

This leaves water only in the crawl space and the feed to the two toilets, which is all pex. My master bed, bath, and office area are add-ons to the original house and are on a slab.
--
Gadgets


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to tberg

Here in Dallas with all the pools there area few companies that are called "Leak Detectors".

I've had them out twice over the last 25 years for pool leaks. Once great and once a disaster.

My friends had 1 out for a leak under the slab. Nailed it for them.

Not cheap. $500 to test, no repairs! Jack hammered the slab and fixed in a day for them.

Good luck. Let us know what happens.


SanJoseNerd
Premium
join:2002-07-24
San Jose, CA
reply to tberg

Years ago I was living in an apartment building built on a slab, and a leak developed under the slab. The landlord called in an expert on locating leaks. The guy spent about 2 hours walking thru the building, listening to the pipes, turning things on and off, etc. Finally he pointed to a spot and said "dig here". Unfortunately this spot was in the middle of my living room. The landlord brought a jackhammer into my apartment, made a small hole in the slab, and sure enough the leak was exactly where the guy said. It was amazing. I suggest calling in one of these experts.


Bob4
Account deleted

join:2012-07-22
New Jersey
reply to tberg

I can see why the main supply line might come up from the slab, but who in their right mind would run any of the other water lines through a slab? That's what walls are for.



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
reply to robbin

said by robbin:

Ok -- so you are thinking it may be possible to see a temp difference with a handheld IR thermometer. Be worth playing with if a person had or could borrow one. Doubt it would be worth the gamble if had to buy it. Good thought, though. I'd try it if I had one.

Actually the OP didn't describe their house. I have, in the past, used a cheap moisture detector on slab, tile joints as well as a hardwood floor to find a leak in a wall. It's amazing how what looks pretty much the same with the eye can have 10 to 20% difference in moisture content. Paid about $35 for mine at Lowes. Could possibly get you within 5 feet or less from my experience.

The moisture detector might be a better option. From the OP's description the leak is about 50 gal/day and the water might cool off quickly before warming the slab. Anything under a slab is a problem to find.


Coma
Thanks Steve
Premium
join:2001-12-30
NirvanaLand
reply to tberg

said by tberg:


Thanks in advance for any tips. Of course, as a DIYer, I don't want to call the pros unless I really have to.


Buy a GPR off of EBAY, find your leak, then return it before two weeks and just pay return shipping.

--
January is National Oatmeal Month

Mr Matt

join:2008-01-29
Eustis, FL
kudos:1
Reviews:
·Millenicom
·Embarq Now Centu..
·Comcast
·CenturyLink
reply to tberg

Depending on soil type and location of the leak with respect to the edge of the slab tunneling can be used to access and repair the leak. I lived in a one bedroom one bath apartment when I moved to South Florida. The hot water line started to leak under the slab. The water heater was behind the bathtub/shower in a closet. The leak occurred in an elbow that connected the hot water heater to the hot water line to the kitchen. The leak was about as far from the edge of the slab as about the width of the bathtub and outside wall or five feet. It took about two days to fix the leak. The first day was tunneling and the second day was the repair and filling in of the tunnel.


garys_2k
Premium
join:2004-05-07
Farmington, MI

1 recommendation

And later the next fitting down the line started to leak...

I'd still just bypass the whole mess.



rusdi
American V
Premium,MVM
join:2001-04-28
Flippin, AR
kudos:2
reply to tberg

There is an option that might solve your problem, I haven't seen mentioned, nor can I vouch for the claims, or success rate for this procedure. I also have no idea of the cost, but it would seem to me that it (should) be cheaper than digging up your foundation.

"Trench-less pipe replacement/repair".

»www.mrrooter.com/Services/Reside···air.aspx

Good luck!


tberg

join:2001-08-23
Greenville, SC
reply to tberg

Thanks for all of the ideas. I have a FLIR E45 in my office. I'll bring it home tomorrow and do some checking.
I'm in South Carolina, so lots of slab houses have all of the plumbing in the slab. My problem is that most of the pipes I can see coming out of the slab are green. Seems that the original installer really loved his acid flux. I can imagine what a T buried in clay for 22 years looks like.
I have engineered hardwood over most of the concrete where I think my pipes run. I'm working on plans to run PEX in the ceiling of first floor. I think I can do most of it through the laundry room and just add 1 bulkhead. In the kitchen, I think I can pull 2 cabinets and access above the ceiling through the soffits.
But, I'll see if it is a simple place to fix first. My mantra is "belt and suspenders" or Plan A and Plan B. I try to have two ways of fixing things in case the easy way doesn't work.