False water meter readings? Need expert confirmation

[Biminibrad]

Hello,
I have a place in a 200 unit complex not in the u.s. Here are the facts..
1. We have standard neptune meters.
2. The water supply is r.o. At .10 per gallon.
3. The water pressure cycles every two minut s from 35 psi down to 6 psi then back to 35.
4. When a unit is not occupied, water bills can be $200 or when occupied several hundred per month.
5. The triangles on the meters routinely spin forwards and backwards.
6. There are no check valves or backflow valves anywhere in the system.
7. We began installing check valves on 8 units several months ago.
8. Those units have seen the water bills drop by as much as 75%!
9. Who would I talk to to get a scientific opinion on this before we approach supplier indicating this has cost us hundreds of thousands of dollars over the years? The meter manufacturer?
Thanks, Brad

 

[Biminibrad]

No one? Uncharted
territory?

 

[frodo]

why the fluctuation in the water pressure ?

fix that and i think your problem would be solved

 

[Chris]

Is this all feed from one larger main line? If so you could put a backflow preventor on the main coming in.

 

[Biminibrad]

Yes, it is coming froma larger main line. Water supplier has been in violation of the agrrred upon 45-55 psi for long time.

 

[frodo]

here is what i would. http://www.necowater.com/

shoot neptune an email to the R&D department, ask them if wild swings in pressure will effect the reading on the water meter

based on the information they provide you with.

I would go from there.

if they say yes it will, I would gather up my past bills and the email, demand they pay the over cost.

 

[Chris]

Also if a backflow preventor fixed the problem on several of them why install a backflow on the main feed?

 

[frodo]

makes since, 1 BFP for the complex instead of 200.

 

[Chris]

I bet pressure go up and turns the meter, when pressure goes down it either turns the meter or not, depending on meter then pressure goes up turning the meter again. Now do this several times a day.

One large backflow preventor will let pressure raise but not fall until bleed off on private side. I bet it would fix the problem for all. Now to convince the district to pay for the install.

 

[frodo]

MY theory was shot down, I emailed neptune, HE actually called me.

it hs a wheel, does not matter about pressure fluctuations, that is not the problem

has anyone checked the piping to the meter for leaks "?

as in, turned off each apartment and watched the meter leak detector to see if it has a leak between meter and building

 

[Biminibrad]

Hello all, i spoke to neptune on monday. One person told me totalizer wold not spin backwards. Some one called me back yesterday and said it would spin backwards with change in pressure. All i know is on the 10 units that had check vlaves put on, water bills have dropped by as much as 100%. I guess the only way, since this is a relatively unchartered area is to my own test. The pressure fluctuates every 3 mins24/7

 

[Chris]

Go out and watch one. Even if they don't spin backwards doesn't mean they are not bleeding down then spinning again when pressure increases.

Pressure goes up = water moving forward

Pressure dropping = water volume leaving the pipe

Then when pressure goes back up it fills the pipe again. It doesn't take a lot of water but over and over again will make that meter spin.

I get the same result when I do pressure tests

 

[Caduceus]

My guess is that changes in flow/back flow are affecting the meters and the check valve is the solution.
I have a new Neptune meter in my house that is specified to prevent water theft, i.e. tapping into the water supply before the meter, and will register back flow/back siphonage as water use and charge for it. When the water company installed it, they checked for my back flow preventer and explained that I would show flow without one.