Hi Guys, need your help with 500G of missing water

Trying to help the in-laws who are on the other side of the continent with their sudden increase in water consumption:

The issue
- Water bill has almost 600 gallons of usage more than any other monthly water bill they've had in the past year (except when they had a major leak between the city and house shut off).
- water meter is slowly running when no water is being used in house

Courses of Action
- shut off every supply valve in the house including the main shut off, the washing machine, and the hot water heater
- check the water meter: not running, it's stopped
- turn on the main shut off = meter still stopped
- turn on the hot water heater = meter starts running
- check for any kind of flow through the heater = no evidence of any water moving through the hot or cold lines, no condensation, no blow off from the prv
- shut the hot water heater off = water meter stops
- turn hot water heater on = water meter starts slowly running
- shut hwh off, turn all other supply valves in the house on = meter is stopped
- turn hwh valve on = meter runs slowly

Thoughts
So it seems to be an issue around the hwh (lol), but there is not one ounce of evidence anywhere around the heater. The house and system is just barely one year old. The T&P valve is not blowing off. They have been losing 3/4 gallons of water an hour without any indication of it. The supply line from the main shutoff to the hwh is very short (within 8'), it's in an interior wall (which hasn't been opened up yet), but there's not one ounce of indication of that much water being present, which I thought would be tough to hide... ANY THOUGHTS MY VALUABLE PROS???

I'm not accustomed to troubleshooting without seeing, but i know you are...

If you have any pipe running under a slab, that is always suspect; but we would have expected a warm spot at least, if not dampness, to be manifest.

leak

That usually indicates a broken hot water line under a slab floor, but we do not know if that is what you have. A hot spot is a definite indicator, but if the water finds another route, it will not heat up the floor.

First, from Mr Grammar Man: it's a water heater, not a hot water heater; if the water were hot, you wouldn't need to heat it, now, would you?

That aside, here's what I did:

I noticed my well pump coming on when there was no obvious water usage, and followed all your steps. However, since I didn't have a meter, I depended on feeling the pipe coming out of the WH. I turned off the inlet, and waited until the outlet pipe got cool, then turned on the inlet. With no hot water being drawn, the outlet pipe got warm pretty quickly.

From there it was a simple task of opening up walls and feeling pipes. I eventually determined the leak was between the laundry (pipe got hot) and the kitchen sink (which was the only fixture downstream from the laundry). I capped off that line, and the problem was temporarily solved. Not permanently, of course, since without hot water at the sink the dishwasher was out of service -- an unpopular situation.

I elected to re-plumb everything overhead. Our area is notorious for under-slab failure of the copper pipes, so I figured it was only a matter of time. I used CPVC, and spent a lot of quality time in the attic -- fortunately, I finished before summer really arrived.

If you don't want to do that, your best option is probably to hire one of the thermal-imaging guys who will come in and take pictures of your floor and identify the hotspot. An alternative would be to just treat it like any other leak and use an acoustic leak-finding service. You didn't say where your in-laws are located, but I can't recommend Sleuth in Tampa highly enough (http://www.sleuthplumbingtechnologies.com/leakdetection.htm). Wherever they're located, there's bound to be somebody like Sleuth around. Usually they won't charge if they can't find the leak, and when they find it, it's usually within a few inches when they say "dig here". Very impressive.

Also impressive -- the drop in my electric bill after I stopped pumping a couple hundred gallons of hot water/day under the slab.

-mike

Here's some bad news........if it's a slab leak, and you fix it......chances are it's going to leak very soon again a foot away or so from the fix...especially if you try to solder it to fix it...(and there's really no other option other than using a compression coupling, and that's NOT an option really, not when you have to bury it in concrete) that will definitely weaken the already weak .......or thin....pipe that's leaking now.
And if its in the kitchen and you have to tear out cabinets to break up the floor there.......well.......
Re pipe if its a slab leak......Florida cost to fix a slab leak....about $825....Florida cost to repipe with two bathrooms.kitchen,two hose bibbs, a laundry, and water heater.....about $2700....using PEX...better than CPVC IMHO.....drawbacks.........HOT cold water because it's from the attic down.
That's why I moved from Florida,that's an unbearable job, I hate attics...120 + degrees up there.

turn on the hot water heater = meter starts running
- check for any kind of flow through the heater = no evidence of any water moving through the hot or cold lines, no condensation, no blow off from the prv


Check your toilet ball cocks. I'll bet you have a bad one, and your water is backfeeding from the input on your water heater. You wont feel any hot water because it is backfeeding from the feed of a tempering valve, or the leak is small enough that the draw is low. Depending on your toilet it could be a leak that you dont hear. It could also be a leaking solenoid valve on a dishwasher or washing machine, or a bad water mixing or tempering valve on a shower, tub or sink. Check the layout of your plumbing before you guess the fault.

hj said:

That usually indicates a broken hot water line under a slab floor, but we do not know if that is what you have. A hot spot is a definite indicator, but if the water finds another route, it will not heat up the floor.

Click to expand...

I also agree with this. When I am called in for a water supply job by a builder in this area, I always insist on coduit to be installed under a slab. I then run my supply lines in this conduit. Makes future repairs easier. Just make sure this is allowed by code.

Fun in the attic

Aw, c'mon Perrycat! Some people pay big bucks to sweat in the sauna at the health club, we get it for free in the attic. I spent some quality time up there Saturday completing a dryer vent project -- 128 degrees. Today I was working in the garage -- only 93. Having re-plumbed with CPVC, I'm now a PEX convert. Good article in the latest Fine Homebuilding that was the final straw for me, but it's too late. I'm not a real fan of cold water, so that downside of attic plumbing doesn't bother me. In fact, I'm thinking of running a long copper loop in the attic in the water heater supply line, with a thermal switch on it to preheat the water coming in to the WH. A poor-man's solar heater. Attic work aside, you're right -- there's no such thing as one under-slab leak. The first one is just that -- the first one. I got a quote of about $5K to re-plumb mine overhead in CPVC.

VAPlumber, I like the conduit idea. That combined with PEX would make a great installation. I wonder why any AHJ would reject that?

What happened to Kristi?

-mike

I'm here, I'm here...
Been away for a couple of days

Mr. Grammar Man, up here in Canada we refer to it as a HWH... if you want to get really particular, you could have warm water stored in there (especially if it's malfunctioning or crapping out), but we would prefer it to be hot - but thank you for the suggestion to change my terminology! lol...

Thanks for all the input everyone, so far it's still a mystery as there doesn't seem to be a hot spot or dampness on the slab (keep in mind, this is being relayed to me over the phone by frustrated Missouri in-laws!), there is no blow off from the T&P, no evidence of flow, warmth, or condensation of any kind, and the only underslab line I've determined from them is between the meter and the main shut off valve inside the house - which shows the meter at a standstill when closed... VaPlumber, I don't think a bad flush valve or leaking solenoid or faulty mixing valve would show such a massive usage of water, do you think? Everything in this house is barely one year old...

On a side note: the contractor/financer of the project informed the in-laws that they were NOT permitted to flush toilet paper into their septic tank... that is absolutely absurd to me, is this standard practice down south (in Missour-ah) as far as you know? I tried to convey to them that modern systems are in place for our convenience, I don't know ANYONE that stores and burns their shi**y toilet paper instead of flushing it! I want to phone the contractor directly about it, but thought I'd ask you first if there was any reason on the planet that a system with rules like that would go in any home...?

Thanks again

Kristi said:

On a side note: the contractor/financer of the project informed the in-laws that they were NOT permitted to flush toilet paper into their septic tank... that is absolutely absurd to me, is this standard practice down south (in Missour-ah) as far as you know? I tried to convey to them that modern systems are in place for our convenience, I don't know ANYONE that stores and burns their shi**y toilet paper instead of flushing it! I want to phone the contractor directly about it, but thought I'd ask you first if there was any reason on the planet that a system with rules like that would go in any home...?

Thanks again

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Have the water district reread the meter; an inaccurate reading or a malfunctioning meter doesn't have to be years old in order to fail/be defective.

Also, the statement on the toilet paper sounds like pure rubbish. I can see that statement being made if someone tried to skimp on the amount of topsoil being brought in so the near future doesn't bring failing leach fields. You wouldn't believe how often that is done to save money so that builders widen their profit margins. Once again the customer becomes the victim long after the homeowner's warranty expires.

Kristi said:

...the only underslab line I've determined from them is between the meter and the main shut off valve inside the house...

Click to expand...

So everything other than the meter->valve line is above the slab? Man, that water's got to be going somewhere, and if all the downstream lines are above the slab, somebody ought to be noticing a big puddle one of these days.

My leak, which was definitely under the slab, produced no evidence whatsoever, other than the aforementioned hot water pipe when no hot water was supposed to be flowing.

As for the shi**y toilet paper, of course we don't burn it. It's laundered and re-used . Seriously, Googling {"toilet paper" "septic tank"} will return about 42,000 hits, most showing that septic tanks handle "modest amounts of white toilet paper" very well. Interesting reading actually -- septic tanks are not just holes in the ground (depending on the contractor,perhaps). Ours has been going strong for 33 years, in spite of one of the other members of the household's immodest use of TP. I'd try to find a local authority, perhaps the UM Extension Service, to use as a reference to persuade the contractor of what's what.

-mike

Quick thought on where this water is going...besides their water bill, how are their other bills? Particularly the ones that would be impacted with 500 gals of hot water being dumped. I imagine if you were losing that much hot water there would be a jump in your gas or electric bill to compensate for the extra water being heated to make up for what is being lost. if those bills are exactly the same, I would lean towards the water escaping is not hot water, not sure if that helps troubleshoot or not. I would also follow the other tips on seeing what is up with their meter (if anything).

Focusing on the (H)WH

You said there was "no evidence of any water moving through the hot or cold lines...". How, exactly, was this lack of evidence determined? Did anybody use a stethoscope or the old solid-rod-in-the-ear trick? Did they try shutting off the WH, returning after the hot line was cold, turning it back on and seeing if the hot line got hot?

You also said "not one ounce of evidence anywhere around the heater...". Some codes require a heater pan, which may drain directly to waste or some other exit point, especially if the WH is in an interior location. Is there any possibility that the WH is leaking into such a pan in a not-easily-noticeable fashion and draining somewhere?

We're only looking for 3 quarts per hour, or slightly over an ounce per minute, which could easily dribble away unnoticed under the right conditions.

I think it's time to call a professional leak detector.

The lack of evidence is determined by checking the temperature of incoming and outgoing water lines from the h(wh)... lol... after many hours of no use, ie: during the night when everyone is asleep. The lines are both as you would expect them to be after a night of no use - neither hot nor cold, just warm from the interior of the house. There is no drain pan apparently, the T&P drains right to the floor... i shuddered as they relayed there was no drain that they could see in the floor - so there's further evidence building up against the contractor.

Good point about checking other bills, i'll ask about that. I wish it was a defective meter, but it's being very clear about when water is slowly flowing and when it is not - and it seems to be when the valve is open to the hwh, but then the hot line should be constantly hot. My theory from here is that there MUST be a line under the slab, you could not lose almost 600G inside walls and not notice (this house is only about 1000 sf). This doesn't make sense to me: if it's a hot water issue, the hot supply should be hot all the time, if it's a cold water issue, why is the meter reacting only to the hwh??? Pieces MUST be missing from this puzzle, so i will try to get a little more info out of them... i've already tried "are you positive you didn't use the shower and washing machine more often this month?", but they are pretty intense about keeping bills down... which is why the alarm went off about the sudden increased usage bill this month.

Time to call in somebody local rather than this plumber from another country! I just don't want them to get taken to the cleaners, which has happened so many times before... sucks to have a plumber in the family and not get to use them...

~k~

One more straw to grasp

Is the water heater hooked up properly? I'm beginning to worry about this contractor, and a slow leak like this might not immediately produce a warm "outlet" pipe if it's actually the inlet side. You also implied that both pipes were the same temperature in the middle of the night, which surprises me. My outlet pipe is always noticeably warmer than the inlet just due to conductive heat transfer, even though the "cold" supply water is around 80 degrees.

-mike

Last resort

http://www.visitmo.com/?source=adwords

Also, the statement on the toilet paper sounds like pure rubbish. I can see that statement being made if someone tried to skimp on the amount of topsoil being brought in so the near future doesn't bring failing leach fields. You wouldn't believe how often that is done to save money so that builders widen their profit margins. Once again the customer becomes the victim long after the homeowner's warranty expires

Click to expand...

Actually if you get out of USA and into some of the lower income area ie honduras they have a trash can for tp. Systems cant handle the sledge from both or somthing. Maybe size if the pipe. You can find hotels that been built to USA standards where it doesnt matter how much tp you dump down.

This ain't Honduras, Duane, this is the good ol' US of A we're talking about... our continents version of poverty is nothing like any third world country out there, and I'm going to to boldly state here that how we manage our waste is THE very reason why we are civilized and not diseased and impoverished. No one should be collecting and storing their tp to protect their sanitary system, it's what our systems are in place for... to protect US!

Isn't that a nice thought fellow plumbers? We are the core of a civilized society ... that should even make MPMark smile with pride...


Hey Mikey, I meant that both lines are what you would expect them to be as in the cold = warmer than cold, and the hot = much more like warm than hot, rather than the two of them being the same temperature as each other. I think there's all sorts of dodgey things that could be going on with the installation, and I'm going to suggest that they get someone in pronto to troubleshoot it in person...

Kristi, What ever happened.