How significant is the amount of gauge movement? See photo

[Gene South]

Guys. Take a look and compare these two photos of the same water meter gauge, particularly the small inner circle “Seep gauge”. At first they appear to be the same however look closely and you will notice barely some movement on the inner circle seep gauge. These two photos were taken 90 minutes apart, one taken at 3:45 pm, the other at 5:15. No one was in the house, all fixtures off, no toilets running, nothing. There is no indication of a leak at the meter or anywhere else. I have never monitored a seep gauge for this long before so I am not sure of the significance of this small amount of movement. I think most home inspectors maybe look at the gauge for a minute or two, but not over 1 ½ hours, so again the significance of the amount of movement is unknown to me.

Background: I am having some heaving, a “bubble” if you will on the slab foundation of my personal home ( a rise in the center of one floor). Since I suspect water is the reason, I am going through a process of eliminations before I spend $300 on a Leak detection company There are three likely possible sources of water getting under the slab. A backyard pool which does not have any apparent leak. I have performed some basic leak test on the pool (2) Ground water, which is likely in this area but the house is 16 years old and never had a problem before (3) and a slab leak. A plumbing company came and did a pressure test, a timed drain test, and did a 5 minute watch on the seep gauge. The plumbing company wrote no slab leak and no problem found in their report. I know there is lots of related things we can discuss about pool leaks, etc but my questions that I am looking for an answer to is this:

Questions

(1) How significant is this amount of movement that I see on the gauge?
(2) Should it be rock steady over 90 minutes?
(3) Is this amount of seep gauge movement within tolerance of gauge
(4) Could it present a tiny leak, or maybe just some nonimal flucuation of the gauge


I don't know, so I am asking

Thanks

Gene

[Benjamin Thompson]

If that is the difference over 90 minutes, I think you need to look for other water sources, I don't see any signs of movement in the gauge. There will be some "movement" as the water pressure in the main line fluxuates.

[John Kogel]

I don't see enough movement in that gauge to lift a concrete slab, do you? :D

[Vern Heiler]

One thing to consider is a leak on the utility side of the meter. This is something I just went through at my daughters business. I also inspected a home a few years ago that had a great sink hole in the center of the crawlspace do to a sewer line leak at the street. These problems won't show up on a meter. I would probe along the main water and sewer easements and maybe dig a few holes. (call before you dig!)

[Jerry Peck]

I think the difference in the apparent needle position is the difference in the angle the photo was taken, making it appear as though the needle moved.

Do you have expansive soil there?

If not, I would look for signs of settlement ... not heaving ... of the walls around that part of the slab.

[Rick Hurst]

Gene,

I don't see any significant movement on your meters there.

We had one yesterday that the meter (diamond) was spinning consistantly and you could see or determine a leak anywhere, and no evidence of movement in the foundation.

In about 10 minutes, we seen about 12 gal. of water flow across the meter and had not a clue. Plumber Recommended!

rick

[Bill Hetner]

I have to join in with others and say I see no movement either on the guages. There is one other trick you might try which is put a screw driver on the intake pipe and listen to see if you hear any water movement that way too. As previous stated it might be a leak before the gauge. also look for other sources of water leakage or springs or underground water sources you never know..

[Gene South]

All good input and thoughts. Thanks Guys.

Gene

[Garry Sorrells]

Heaving / bubble ? How much of an upward deflection do you have and over how much of an area?
Divide and conquer:
1) Have you tested the moisture content of the floor in various area of the floor?
If not, do so with a grid on paper every 2 sq ft, recording your readings

2) Install pressure meter on main supply from public source and isolate via shutting valve at street and house entrance. Leave for 3 hrs and see if drop in PSI, no change = no leak.

Test interior lines for pressure loss.

A little loss adds up to allot over time.

3) Do a core sample of slab area you are concerned about. Exploratory surgery is some times the only way to find the problem.

4) Take core samples and test moisture content from perimeter of foundation.

[Dan Rote]

Gene, Slight movement of the "seep" dial is NOT enough to heave a slab. However, if the incoming water service is under the slab it is very possible that it is on the street side of the meter which would not register as water used. Is the heave in the slab close to any water using fixtures, if it is then spend the money for a PROFESSIONAL locater, if it is not close to water using fixtures, you could drill a 1/4" hole in the middle of the heave and see if you get and water back.