Water meter question

[Reis Pearson]

Today I went to a clients home to look for a suspected leak. I couldn't find anything to suggest that there is one, but the reason that the client called was because she had pulled up the cover on the water meter box and the "dial" was moving. The "dial" in question is one of three (in the attached photo it is the dotted line)... two of them are arrowed pointing at numbers and the third is a grey, pronged dial. The grey, pronged dial spins clockwise then counter clockwise. My understanding would be that this is a meter without a check valve and the reason why the dial spins back and forth. I checked readings twice approximately 20mins apart with no change in the counter. Anyone know anything more helpful?

[Jim Luttrall]

I can't tell much from you diagram, but around here I see a small triangle or a round notched dial as the minor movement meter.
You are correct in your assumptions about the minor movement indicator "rocking" with pressure fluctuations.
With no continuing forward motion, all is well.
Turn on a faucet while watching the meter and you will get a good idea of how much water it takes to spin the dial, it does not take much.

[Jerry Peck]

That's a flow indicator, as Jim said, most (but not all) the ones I've seen were red triangles. They move at the slightest water flow.

If there is a leak, they will show it.

Moving back and forth indicates the water is moving back and forth, which could be thermal expansion, water being used elsewhere (down the street, at a main, fire hydrant, etc.) which allows the pressure to fluctuate.

Moving backward is not a good thing as that means water which already went past the meter is going back through the meter and into the city lines, water which could be contaminated.

Not sure if water meters read only one way or if back-flowing water backs the meter up??

If the meter reads with backward flow (reduces reading), then that is not too bad meter reading-wise, however, if the meter only reads forward, you could be paying for the same water many times over.

Regardless, that is not a good thing (water-wise).

I'd recommend calling the city. They will likely install a check valve or a pressure regulator, either of which will stop that. Make sure there is a thermal expansion tank installed.

[Vern Heiler]

I'd recommend calling the city. They will likely install a check valve or a pressure regulator, either of which will stop that. Make sure there is a thermal expansion tank installed.

Make that a "thermal expansion device". There could be one installed at the water heater or in one of the toilet tanks.

[Reis Pearson]

Thank you gentlemen!

[Jerry Peck]

Make that a "thermal expansion device". There could be one installed at the water heater or in one of the toilet tanks.

No, I intentionally used the word "tank" as that gives better protection for thermal expansion.

Had I used "device", then someone would install a pressure relief valve and tie it into the T&P safety relief valve discharge line. :(

I was not stating what the minimum code requirements were (i.e., what "shall be installed"), simply what "should" be installed for best performance.

[Jerry Peck]

I have never seen a water meter calibrated in cubic feet. Is that the norm where you are?

There were many areas in Miami-Dade county where cubic feet meter were used, typically in Coconut Grove and Coral Gables areas.

[Vern Heiler]

No, I intentionally used the word "tank" as that gives better protection for thermal expansion.

Had I used "device", then someone would install a pressure relief valve and tie it into the T&P safety relief valve discharge line. :(

I was not stating what the minimum code requirements were (i.e., what "shall be installed"), simply what "should" be installed for best performance.

Jerry what makes you belive a tank is better than other devices used to releave thermal expansion? Thermal expansion tanks are prone to leaks, there may already be another device installed in the house, and to install another type of device is much less trouble and less expensive.

[Jerry Peck]

Jerry what makes you belive a tank is better than other devices used to releave thermal expansion?


Because thermal expansion tanks do not discharge water, the bladder moves up and down allowing for the expansion of the water.

Other methods relieve thermal expansion by releasing the excess pressure, that means releasing water, which goes against every other water saving requirement in the codes.

[Vern Heiler]

They will likely install a check valve or a pressure regulator, either of which will stop that. Make sure there is a thermal expansion tank installed.

And if there is already another device installed would you still recommend installing a thermal expansion tank?

[Jerry Peck]

And if there is already another device installed would you still recommend installing a thermal expansion tank?

If I cannot "see" the other device, yes. There is no harm in it. In fact, the thermal expansion tank may make 'the other device' no longer needed.

If I can see there is a pressure relief valve, well, that *is* one of the allowed alternatives, but I seldom see them piped correctly for discharge.

[Vern Heiler]

If I recommend a thermal expansion tank be installed in the summary, and there is already a device installed, I'll get my jock-strap snapped by the licensure board. (the seller can make a complaint)

[Jerry Peck]

If I recommend a thermal expansion tank be installed in the summary, and there is already a device installed, I'll get my jock-strap snapped by the licensure board. (the seller can make a complaint)


Even one you cannot "see" (i.e., you cannot see one, so you presume one is not installed), as I stated in my post?

If even then, sounds like the licensure board needs their bra straps snapped back in return.

[Jim Zborowski]

I'd suggest contacting your local plumbing inspector. A lot of towns are requiring an expansion tank and backflow prevention valve. Where I'm at, any time you change a water heater you are required to make those updates.

[B___D__]

That's a flow indicator, as Jim said, most (but not all) the ones I've seen were red triangles. They move at the slightest water flow.

If there is a leak, they will show it.

Moving back and forth indicates the water is moving back and forth, which could be thermal expansion, water being used elsewhere (down the street, at a main, fire hydrant, etc.) which allows the pressure to fluctuate.

Moving backward is not a good thing as that means water which already went past the meter is going back through the meter and into the city lines, water which could be contaminated.

Not sure if water meters read only one way or if back-flowing water backs the meter up??

If the meter reads with backward flow (reduces reading), then that is not too bad meter reading-wise, however, if the meter only reads forward, you could be paying for the same water many times over.

Regardless, that is not a good thing (water-wise).

I'd recommend calling the city. They will likely install a check valve or a pressure regulator, either of which will stop that. Make sure there is a thermal expansion tank installed.

"Contaminated" with what sir? I know that this is the language used to justify the reverse flow prevention. But what kind of contamination is possible? Are we talking about homes that use lead pipes while the municipal water lines are non-lead?