Need help....

Have a new 5/8 meter flowing 28 gpm at house side of meter, proptery goes up a 10 ft incline to house

If you say you have 28 GPM that should mean you have approximately 29 PSI correct?

3/4 pex main line 75 ft long,to main valve, a 3/4 gate valve.

Is the gate valve full port type and fully open?

then 10ft to water.

The 3/4 line runs thru the house for another 70ft. All branch lines to units are 1/2 pex. I have approx. 34 units total as per BMS 79 demand weights chart. 3 bed 21/2 ba 2400 sq ft. single.

Have only 9.0 gpm going thru elct flow meter on water softner, high flow sears 800 softner. I only see a small reduction in flow, maybe 1 gpm with softner on. All plumbing 3/4 pex or copper at these points.. With an oval tub running and 2 sinks and kitchen sink on, the kitchen sink at other end of house flow is about 1/2 gpm...out of kitchen sink.

I am out of water??????

Am I really running out of water or a pinched 3/4 main pipe???..

This is a new house, plumbing contractor playing the blame game on City water dept...I had the city flow the meter rate was 28 gpm...What a chore...No one wants to get involved... Is the 3/4 main too small,is

meter to small..

Increasing the meter will give you more VOLUME not more pressure.

If the city is giving you 65 PSI =28 GPM and you increase the inlet piping to 3" diameter your still going to get 65 PSI and a flow rate of 630 GPM.

The problem most likely is the incoming pressure which I calculated to be around 29 PSI then you have friction losses through the valve and the 10 ft height gives another 4 PSI loss.

I think the plumber if she/he had followed the code as far as sizing the water lines and took the available pressure into consideration with friction losses and pressure drop then I would look at the designer who did the specifications of the water lines.

I personally would not use plastic for domestic piping and if I had used copper I could install a pressure booster tank but not knowing the design factor of your system or the bursting strength of the piping and or fittings I think someone should go back to the drawing board and recalculate the fixture demand and developed length.

I find it amazing how many so called experts love to blame the city water supply.

In NYC I expect the city to get water to the inside of a building (basement) and it is totally up to me how it gets to the 47th floor of a building.

I have for an example a home with 12 rooms over 11 with 6 bathrooms (including the basement) and 2 kitchens and a laundry room and I have an 11/2" water meter with city pressure varying from 40 - 60 PSI and all lines branch off either an 11/2 or 11/4 main so there is no noticeable drop in volume even with 2 bathrooms a laundry and dishwasher all going at once

I do not have the nerve to try to supply water to a home with any main less then 1" main even for one bathroom and a kitchen and possibly a laundry room.

To each his own I guess but I would rather have the pressure given to me rather then a flow rate as when you know the available pressure then all one does is punch out the fixtures and developed length and other factors then add in a fudge factor for future add on's.

Friction loss and water demand has to be calculated or your spitting into the wind as you can only suck some much liquid through a straw no matter what pressure you have available

I am sorry left out the psi at the house hose bib 60 psi 28 gpm out of the meter house side....plumbing free style not manifolded 90 and ts used through out I think the pex is 200 psi rated....tough stuff.

Did you do a bucket flow test on each tap. The tub is probably 6 to 10 Gpm. Each tap should be capable of 4-6 Gpm. With the length and config you described it sounds like the flow restriction is your problem. That flow through your water meter was probably open discharge at 0 Psi.

You need to do hydraulic calculations to know what you got and what you require. It is that simple.