house loses pressure when main is shut off

[LazyPup]

dean,,

In my region they are now installing digital meters that do not have a flow indicator.

By taking ten minutes to work out the math I can then conclude the reported consumption is nearly 1000 gal/day which is simply too great to warrant searching for a leak.

While we could guess a toilet, they already indicated in the post that the toilet valves had been checked. Given that a toilet typically fills 1.5gal/min that would work out to 90gal/hr. In order for a toilet to cause a loss in the amount in question it would have to remain in full fill mode for nearly 11.1 hrs/day. Again, the math indicates it is simply to great to even bother double checking.

In fact, the math indicates the loss to be neary 5 times the normal daily consumption for a structure this size. Given that most water meters are inside the structure, we can instantly rule out a leak on the main line from the street, as any water leaking there would not be indicated on the meter.

A leak of 1000 gallons would fill an area of 1600sq.ft and inch deep, which would mean it would be 1/2" to 1" per day in a typical basement. Any leak of that proportion would be blatantly obvious so there should be little need to worry about zone pressure drops or fittings dripping. Either there is another major unreported consumption, such as lawn irrigation or the meter is faulty.

[Dean]

I don't remember ever seeing a digital water meter (but then there are many other things I don't remember either) so please excuse my ignorance but can you not run a simple "shut in" test with one?
Seems like a digital meter should somehow still show water flow passing through.

So Eric, can't you just run a "shut in" test with your meter?

[ewmyers]

Hi Dean, I did a "shut in" test right off the bat. At first I just made sure everything was turned off, then looked at the low-flow indicator on the meter, and it wasn't turning at all. That's when I called the water district to come out and take a look, and they found the pressure drop in the house. They didn't want to check the meter until that got resolved.

Now that I can visualize the magnitude of the discrepancy, I can pretty much rule out a leak anywhere on the property. Even if there was a constant flow of water, but just below the ability of the low-flow indicator to register, it still wouldn't account for the amount of water use that shows on the meter. There is just no way that a 1,000 gal/day leak would not become very obvious very fast.

So my meter isn't a digital one, but they read it by driving by and picking up a radio broadcast from it. The numbers on the bill match the numbers on the meter, so that's not part of the problem. I will call the water district tomorrow and ask them to come test the meter.
-Eric

[ewmyers]

So here is the latest update. First, I tested my water meter's accuracy, and was not impressed. I read the meter, drew 15 gallons through the hose, then reread the meter. It should have shown an increase of 2 cubic feet, but instead showed 3. Then I drew 7.5 gallons and checked the meter. No change, the meter hadn't incremented at all. I repeated the first experiment, and the meter showed another 3 cubic foot change. OK, the meter is wonky (thats a technical term).

Next I called the water district, and was able to verify that the meter is supposed to show cubic feet, rather than having been recalibrated or some such thing. The bill is actually in CCF (hundred cubic feet), and they get that by simply reading the first 4 digits and not the last 2. Well, that appears to be my main problem, because when my meter said 026301, the bill showed the reading as 2630, not 0263. They are investigating, and will get back to me on Monday.

LazyPup, I used your math and numbers on them, and they were quickly convinced of the magnitude of the problem. THANK YOU!

-Eric

[ewmyers]

The Water district called me back just now and confirmed that their readings were off. They corrected my account in their system and are refunding the overcharged amount. They seem less open to the idea that the meter is wonky, and I think I will retest before pushing that issue with them.

Thanks again everyone!

[LazyPup]

Thank you for letting us know how it all came out. If you like to crunch the numbers here are a couple more that may help you sort it all out.

While some may feel it is unnecessary to work out the math, as you can see, had we not taken the time to work it out you might still be running yourself silly looking for drips and leaks.

The basic rule of thumb for rough estimating is 8 gal. per/cu.ft but that has a large margin of error.

one cubic foot is 12" x 12" x 12" =1728 cu.in.

I gallon of water equals 231cu.in.

1cu.ft of water equals 1728 / 231 = 7.48 gallons.