Wall thickness does not affect pipe or tubing size.[20] 1/2" L copper has the same outer diameter as 1/2" K or M copper. The same applies to pipe schedules. As a result, a slight increase in pressure losses is realized due to a decrease in flowpath as wall thickness is increased. In other words, 1 foot of 1/2" L copper has slightly less volume than 1 foot of 1/2 M copper.[citation needed]
Needed to replace a water pressure regulator.  Looking at the retail costs of the regulator, they seem to run from abouit $60 to over $300 for one that includes more that the basic control of water pressure in the house.  Had not used a pro plumber for over 20 years so I was not up on the costs associated with needing their help.  I was contacted by at least 3 plumbers but only one, Right Now Plumbers, gave me an instant quote of $394  for the service without me even asking. Although I thought this price seemed a little high for a job that takes less than an hour to complete, I accepted their service.  Must say that the job was done very professionally and would use them again if needed.  However,
I was disappointed with the pressure of a tub and shower that were plumbed with 1/2 supply lines (2nd floor). Could be low pressure from the street, but I want to replace with 5/8. Plus, I'd like to have 2 back to back showers, one inside and one outside. So, I had intended to bring a 1 supply to both, then branch up to valves and shower head with 5/8. Finally, I thought pressure from the street was typically 55 to 70 psi and I am concerned if pvc can take that.Any thoughts?

Rooter Plumbing