You could disconnect the water line before it enters the house, connect a garden hose at the washer hook up from your neighbors house and blow backwards. If there is any debris trapped in the line, this will free it up.

If the service line from the meter to the home was galvanized or iron then more than likely flow restriction was the reason the house was re-plumbed but they may have treated the symptom and not cured the disease. You can have adequate static pressure with limited flow from clogged pipes as demand for volume increases.

If you know what you're looking at you can look in the meter can and usually determine what type of pipe is coming to and leaving the meter. If you don't know then call a plumber.

kotlevich said "I had a few plumbers over: they either suggest changing water main to the street, installing expansion tank or changing the pipe from entry to the house "
To which lurker replied "determine what type of pipe is coming to and leaving the meter. If you don't know then call a plumber."
That is why I have an understanding that what they say is needed actually cures the problem or else they are not paid. Put it in the contract before signing it.
Amongest all those plumbers,did they determine #1 if that main valve (possiblly hidden) is fully open where service enters house? Some digging might be required o find the valve. #2 if pressure equally drops at front yard hydrant (if meter is at front) ? #3 if meter cut off is fully open? Until you are certain full flow is reaching the house,it's usless tinkering with remainder of house.
3/4tr line is of ample size. Solutions are best found through process of elimination,not throwing parts and labor money at them..

I can not conceive of a circumstance where installing an expansion tank will alleviate low flow under higher demand and that statement from any of those plumbers concerns me IF the OP reported that statement accurately.

It may be that a plumber advised replacing the service line from the meter to the home and advised adding an expansion tank to bring the installation up to current code.

I agree with klem and would make sure all the simple things were checked and correct before serious digging in the ground or into the OP's wallet.

I'd expect that the plumbers consulted did check the main meter valve and main shut-off and PRV if installed in the home before they made any recommendations... but we don't know.

thank you for your responses.
the line to the house is 3/4 copper. i do not have pressure reducing valve and i do not have a shut off valve at the curb(its not uncommon in our city, all confirmed with water company)
none of the plumbers guaranteed results.
its a great idea to put it into contract.
t however, what is the next step? i was thinking of taking off water meeter, attaching there pvc pipe 3/4 with a tee to measure dynamic pressure. if pressure drops when sinks are on, then the problem is before the house, if is does not, then the problem is between the 2 points where i measured pressure.
does that make sense to you?
if the problem is in service line, can booster pump patch it, or i have to change the line?

"I can not conceive of a circumstance where installing an expansion tank will alleviate low flow under higher demand..."

You may be thinking of a five gallon expansion tank supplying an air cushion. I suspect the idea is for a hundred gallon wet storage tank with an air bladder to keep the pressure. Think of a well with a deep feed where you can only draw at a low water rate. You'd probably install a big pressure tank between the well head and the tap to store a volume of water under suitable pressure that you can draw from, and the well pump would, if the tank was sized right, catch up after you were done with your demand. Heck, it could take hours extra as long as your demand was satisfied. Now put one in the basement, or better, outside at first floor level if freezing can be avoided. In the attic is just begging for trouble.

A tank is also perhaps one of the cheapest fixes, although the supply problems may get worse over time. Since the house has had major plumbing replacement, all problems point to the street, maybe on the house side, maybe the municipal side. 3/4 copper from the curb to the house is a little cheap, pressure-drop wise. I like the possibility of a broken or corroded shutoff valve somewhere in line, especially since there's one that even the city can't find, so double check that "no street shutoff" claim. It sounds really amateurish to have none anywhere. How did they replace the house line without one? Did they shut down the neighborhood?

This post was edited by grubby_me on Thu, Feb 5, 15 at 14:52

i will check with the city and try to be more firm with water company regarding the curbside shut off valve. the house next to use has it, however, our has just a blue line drawn on the side walk and letter W, so its marked without the valve
what are your thoughts on booster pump that cuts in when pressure drops in the line, is that a possibility.

kotlevich, It seems like you ask for advice you have little intention of takeing unless it agrees with your locals that have failed to fix the problem. Everyone here is telling you there is a main cutoff valve and I'm willing to wager there are two,one before meter and another after meter and before house,likly within three feet of house. It's the law regardless what kind of hillbillies run a public water supply. If both are not present,do everyone in your area a service by contacting your state natural resources dept. I see you joined GW to post this thread. You need to get on board and tell us how you KNOW THERE IS OR IS NOT A RESTRICTION BETWEEN METER AND HOUSE. Although illegal, your idea of a tee in place of the meter is a good start. Let us know the result.

Water meter is located in the basement of the house.
I am willing to take your advice: however what is the advice: you think there is a shut of valve, my house located 25 feet from water main on the street, it's all concrete, so if the advice is to dig up all the concrete to find the shut off valve, then I will also replace the service line, same labor.
We have water service to our area, water company told me that there is no shut off valve and that it's common in this area where most houses are over 100 yrs old, that's all.

grubby,

I favor curing the disease instead of treating the symptom.

Agree, how can I be 100% sure that this is where the problem is.
Because repair is very expensive I want to be certain that it will cure the problem.
That's what I'm looking for

Follow-up:
Klem,
Pulled all old permits from town and found that service line was changed to far side main in 1995 with 3/4 copper line.
No mention of shut off valve.
Called the main plumbing inspector in town who told me that 20 yrs ago shut off valves were not mandatory and that it is likely that the house never had it.
What should I do next?

Ok,this is becoming increasingly clear you need someone on site to track this down. You keep asking deep questions that are difficult to answer but if you are prepared to act on information I'll try to get you started.
Purchase a 3/4" full port push fit (aka shark bite) ball valve. Dig up the main supply at the point where public owned and your privately owned lines meet. Ask plumbing inspector dude to turn water pressure off for 10 minutes while a valve is installed. Remove 12" of line then push ball valve onto incoming flow side. Ok,there's your means of turing water supply off any time you like for as long as you like. You can splice missing pipe with a compression coupling but it would be better to use a solder coupling without stop. You might also install a tee with hose bib while splicing pipe so you have an easy test port in valve box. You can now turn pressure off and install test ports as nessary.
If inspector dude refuses to turn pressure off. Cut the line , shove the open valve on then close valve and go put on dry clothes.

Klem, thank you for your input.
I would love to have someone knowledgable on site.
The thing is that I live in the city and the set up is such that my house is located about 20 feet from the street, so there street, then sidewalk, then concrete in front of the house. Service line enters the house about 5 feet below grade in the basement and that's where water meter is installed.
So to dig the line outside the house you need to break up the concrete. That is the reason I thought of taking off water meter and using this break in service line to install pressure gauge to measure dynamic pressure.
There is a shut off valve before and after meter. So I should stay dry
I only keep dragging my feet on that because temp was in the 20s , I was worried in case Something goes wrong and there is a delay in reconnection the line, pipes might freeze, so I was waiting for weather to get warmer.

Water meter with shut off

Another view of same thing

Hi,
Do you have pressure regulator? If you do you may want to check that out.
Woodbutcher

Woodbutcher,
Its a great thought, but do not have one.
Kotlevich