How to locate slow water leak located in the home

[DanAyo]

It appears I have a very slow water leak that is locate between the shutoff valve at the water line entrance to the home. I say this because when the main water shutoff at cement foundation of the home is shut off, the water wheel on the water meter quits turning. When the home water shutoff valve is opened the water wheel turns so slow that it needs to be watched for a while before any movement is noticed. I calculated that a point on the wheel moves 90 degrees in a minute or so. When the home shutoff is closed the wheel remains stationary. If my rough estimate is correct, it appears ~2 gallons of water is leaking in a 24 hour period.

My home is built on a slab. The water lines are copper and run under the slab. Tomorrow I plan to disconnect the washer hoses to check for leaks. I will shut off the toilet water. I see no visible signs of water leakage inside. The main shut off appears to be dry, especially checked the home side of the valve. To be safe maybe I should also turn off the the water line vales to all faucets. The hose bibs are dry.

I appreciate any help offered!
Thanks in Advance,
Dan Ayo

 

[Twowaxhack]

You need to determine if the leak is hot or cold water.

Turn the cold water valve off on top of the water heater. If the meter stops turning then you have a hot water leak.

If it doesn’t then you have a cold water leak.

This will help you when you start looking for the leak.

If the leak is cold water then you could turn off the toilets to make sure a ballcocks not leaking.

 

[DanAyo]

I don’t t have any valves on the hot water heater. Is there a work around or should I install a valve on the line?
Thanks for the reply.

 

[Twowaxhack]

You need a valve on the cold water supply at the water heater. This way you can isolate between hot and cold leak

 

[RickFlorida]

If it's around 2 gallons of water in just 24 hours and you don't see it in the walls or floors...doesn't the leak have to be inside the concrete slab? So you don't even need to find that leak. You unfortunately have to just go ahead and repipe the house. Doesn't it cost more to dig up the slab, replace the pipe only where it leaked (and thus leave all the old pipes elsewhere under the slab to leak again later), then repair that section of slab, then replace flooring..... It's cheaper to just reroute/repipe whole house. I'm not a professional but this is my understanding.

 

[havasu]

I've been told a professional leak detector can pinpoint via sound to less leakage than you are showing. Then again, he will probably point to an area about 2' in diameter. Either you dig down, thru your flooring, thru your slab, down another 6", find the leak, then repair, cover, refloor....I hope you are catching my drift. Punch a few holes in the drywall and go up and over to all wet locations.

I myself chose the more expensive option, and now regret not just repiping.

 

[RickFlorida]

Can I share some knowledge since I have a Florida house 1957 with copper in the Terrazo slab? What we do in this neighborhood is this:

Once the copper in the concrete slab goes... we simply repipe like this: Uponor PEX from the service line outside into the garage, through the small attic (you have to be skinny and crawl on your belly) and then we drop the PEX through the walls and then we have a guy simply punch out the wall to put new valves on the brand new PEX we just dropped through the ceiling. You have to do this for just the kitchen and two bathrooms. The plumbing to the washer dryer is already on wall exposed. This is WAY, WAY cheaper and faster than digging up flooring, slab, and only repairing ONE section of the old copper in the slab. Why the heck doesn't everyone do this? The only downside to this method is that if it's summer time, it's too dangerous to go in the small attic crawling around on your belly in 130 degrees. You could die from heat exhaustion or go into a coma so you can only do this job in the winter. I wonder if that is why this method is not 100% common?

 

[havasu]

I will tell you my reasoning. The area I live in is surrounded by fruit trees, with lots of rodents, especially rats. Once they get into the attic, if they chomp on rat poison, they will eat the PEX creating holes which will flood a house in no time. This leaves repiping with copper pipe. Because now you are dealing with sticks that need to be soldered in, more holes must be made in the drywall, and just the drywall repair will be in the $ thousands of dollars. Not to mention kitchen cabinet removal, dealing with vaulted ceilings, meaning you would need to break the stucco in several places, which would be another few thousands to repair. Then, if you are fortunate to match all finishes, you would need to spend another few $ thousand to match the paint.

Another concern is the leaking line led directly to two bathrooms, which are back to back. The connection to the bathrooms is right against the shower walls, meaning I would need to demo one shower wall completely out just to reconnect overhead plumbing, then I'd need to reinstall new concrete backerboard and retile one full bathroom, which would be another few $ thousand.

Yes, I have spend $800 to rat proof the attic, and so far, so good, but this is why I decided to punch down rather than repipe.

 

[RickFlorida]

Ah, good point. I didn't think of that. If money is no object, I would like nothing more than brand new copper, properly sleeved, and inside new Terrazo. Brand new Terrazo is like 30 dollars a square foot to lay and polish! We have to do what we have to do. Also, since Florida is so damn hot, we really seal our attics really well. I didn't see a single sign of rats or mice in my sealed attic so I think my method will be okay for me. I always prefer to replace my pipes with copper when they fail (I have not had to repipe my house yet). The reason guys in my neighborhood drop PEX through the walls and ceiling is because it's obviously more flexible and faster/easier.

 

[DanAyo]

I appreciate all of the replies. I think I may need to contact a plumber.

I shut off every water valve in the house. Washer, sinks, toilets, outside hose bibs. The only things that don’t have valves are the hot water heat and both shower/tubs. I did open the inspection covers for the tubs and both of them are dry. Also closely inspected the home side of the shutoff water valve to the home.

I know the roll of copper tubing was never spliced below or in the slab.

Can anyone suggest other ways to trouble shoot this issue. I may put a valve in the cold water pipe at the water heater. Looking into that at this time. I see no leakage in the house

 

[RickFlorida]

Good luck, hopefully you get lucky and it's an easier fix than what it could be. Not sure what you mean by "copper was never spliced below or in slab".

Do you mean you doubt the copper is leaking in the slab because they don't have a lot of soldered connections? There are still going to have to be soldered connections for the copper that is in the slab or under. What I heard can be a problem is if the copper pipes that is in the slab of concrete or even under it was not "sleeved" to protect the soldered connections.... this is where they fail first under the slab. But you correct that solder connections is where you first get pinholes in general. My 1957 house had this happen in only one place so far. I had a pinhole leak at a soldered joint in the wall.

If you are losing 2 gallons of water every 24 hours and you don't see water on floor or in walls.... your leak has to be in or under the slab. Hope I'm wrong because that means re-pipe time. Which I think is 7,000 to 14,000 if you pay someone.

But like Twowax says, make sure it's not just a running toilet. I bet a running toilet is more likely to be a cause of losing water and not seeing the water.

 

[Twowaxhack]

Good luck, hopefully you get lucky and it's an easier fix than what it could be. Not sure what you mean by "copper was never spliced below or in slab".

Do you mean you doubt the copper is leaking in the slab because they don't have a lot of soldered connections? There are still going to have to be soldered connections for the copper that is in the slab or under. What I heard can be a problem is if the copper pipes that is in the slab of concrete or even under it was not "sleeved" to protect the soldered connections.... this is where they fail first under the slab. But you correct that solder connections is where you first get pinholes in general. My 1957 house had this happen in only one place so far. I had a pinhole leak at a soldered joint in the wall.

In modern construction you rarely if ever locate a joint under the slab on copper water pipe. If you do make a joint under the slab it must be silver brazed.

The sleeving is only placed where the pipe is in the concrete. Concrete will eat copper, also there’s expansion and contraction.

 

[Twowaxhack]

I rarely break the slab. I determine if it’s hot or cold leak then find the manifolds in the walls. Then isolate the leak and go over head through attic typically, not always

 

[RickFlorida]

I rarely break the slab. I determine if it’s hot or cold leak then find the manifolds in the walls. Then isolate the leak and go over head through attic typically, not always

Thank you. I did not realize this. I had simply assumed they had to solder at least in a few places under there but I was totally wrong here. Thank you! No wonder the copper in my terrazzo from 1957 has not failed yet. Now that you mention this, I do remember seeing photos or maybe seeing in real life myself that they simply bent the copper pipe up from the terrazo slab where it was horizontal to vertical to be used in the wall. Now I realize this was so that no soldered connection was in the slab to fail. You teach me a lot of things Twowax!

 

[DanAyo]

Good luck, hopefully you get lucky and it's an easier fix than what it could be. Not sure what you mean by "copper was never spliced below or in slab".

Do you mean you doubt the copper is leaking in the slab because they don't have a lot of soldered connections? There are still going to have to be soldered connections for the copper that is in the slab or under. What I heard can be a problem is if the copper pipes that is in the slab of concrete or even under it was not "sleeved" to protect the soldered connections.... this is where they fail first under the slab. But you correct that solder connections is where you first get pinholes in general. My 1957 house had this happen in only one place so far. I had a pinhole leak at a soldered joint in the wall.

If you are losing 2 gallons of water every 24 hours and you don't see water on floor or in walls.... your leak has to be in or under the slab. Hope I'm wrong because that means re-pipe time. Which I think is 7,000 to 14,000 if you pay someone.

But like Twowax says, make sure it's not just a running toilet. I bet a running toilet is more likely to be a cause of losing water and not seeing the water.

“Not spliced under the slab”
In other words there are no joints or couplings in the tubing that is under the slab.

 

[Ole Dodge]

It may be necessary in FL., to have slab. But, I would always choose crawl space over slab mainly for all the issues described above.

 

[Twowaxhack]

The problem with crawlspaces is our high humidity. So that means to do it right the crawlspace has to be encapsulated. That’s expensive and it’s a maintenance issue forever.

The ground doesn’t freeze here so a slab protects your pipes and is easy to seal with a vapor barrier. Some even choose to install all the water pipe in the attic, so you’re only left with pvc dwv under the slab.

It’s just cheaper to build on a slab here is the answer really.

If you have an open crawlspace and you keep your thermostat cooling below about 75 degrees, you most likely have mold growing under your house here. Bet the farm on it.

 

[Ole Dodge]

You’re probably right. I’ve thought about the encapsulation but like y’all said, it’s expensive.

 

[DanAyo]

It appears I have a very slow water leak that is locate between the shutoff valve at the water line entrance to the home. I say this because when the main water shutoff at cement foundation of the home is shut off, the water wheel on the water meter quits turning. When the home water shutoff valve is opened the water wheel turns so slow that it needs to be watched for a while before any movement is noticed. I calculated that a point on the wheel moves 90 degrees in a minute or so. When the home shutoff is closed the wheel remains stationary. If my rough estimate is correct, it appears ~2 gallons of water is leaking in a 24 hour period.

My home is built on a slab. The water lines are copper and run under the slab. Tomorrow I plan to disconnect the washer hoses to check for leaks. I will shut off the toilet water. I see no visible signs of water leakage inside. The main shut off appears to be dry, especially checked the home side of the valve. To be safe maybe I should also turn off the the water line vales to all faucets. The hose bibs are dry.

I appreciate any help offered!
Thanks in Advance,
Dan Ayo

For those that believe in miracles - this makes sense
For those that accept unexplained phenomena - maybe not surprised
BUT for everyone else - how is this explained?

I have watched the water wheel on my meter on at least a dozen separate occasions. The movement of the wheel was always consistent. When the house water supply was shutoff at the home the wheel stopped. When the valve was opened the wheel would very slowly spin. Today a ball valve was installed on the cold water inlet of the water heater. Went to the meter at the road and called my wife in the house. She closed valve on the cold water pipe - wheel remained stationary. Then she opened the hot water heater valve was opened - the wheel REMAINED STILL!

Checked the meter ~4 hr later and wheel is still stationary.
Can anyone venture a guess as to what may have happened?

I really appreciate the help rec’d,
Danny Ayo
Thibodaux, LA

 

[havasu]

Well, probably the same thing that just happened at my vacation home. My water bill was 4 times the normal. All lines inside are shut off with a ball valve, and sprinklers were off. Drove 4 hours to check and the city side of the meter was completely sheered off, probably by a passing donkey. The meter was spinning with no water passing through the meter. Seems city has corrupt meters that spin when it senses flow on the city side?