Plumbing and Piping - Low water pressure

I think I'm about to have a big fight with my builder over water pressure.

Is there some established standard for acceptable flow rates or pressure for residential plumbing?

How much should flow rate drop from the street to the back of the house?

I think most of the plumbing is in the slab-if this is the case, can anything be done to improve the situation?

Hi,
City water pressures vary throughout the country. I know of cities that deliver water to homes in the 80-90 psi range, and cities that deliver less than that. Where I live, city pressure is about 40-45 psi, which is sufficient for us. At higher pressures, regulators are used to set pressures where needed.
Plumbing fixtures (faucets, etc.) are rated for certain gpm and pressures, i.e. 2.5 gpm @40 psi.
A qualified plumber should be able to do a tally on the fixtures in the house, and arrive at the amount of flow and pressure needed. If the house is a two story, this must be taken into account also. If the pressure is a given, like in my town, the piping and fixtures are designed to work within these parameters.
If pipe sizing is done correctly, the loss will be minimal from front to back.
I have to take into account all of these same things when I spec a water well pump for a customer.
Hope this helps.
Ron
http://www.peekspump.com

Wow! Thanks for the prompt reply!

I don't know what my pressure or flowrate is, but there is a tremendous difference between the hose bib on the front of the house and the tub in the master bath.

Any advice on how to improve on my problem, since it will be difficult to properly "RE-SIZE" my supply pipes. Is it common for new construction to have dirt or some obstruction that needs to be cleared?

How new is this house, less then a year call back the contractor.

All plumbing should be operating properly in new construction, there should be obstructions in the water system.

And don't forget to clean all faucet aerators and showerheads of debris.