: I am having a house built, the contract called for 1 inch water service, I noticed that 3/4 inch pipe was installed. When I asked my builder about this he said he thought that 1 inch pipe was a typo on the contract, and residential is always 3/4 inch. My concern is that the house has 4.5 bathrooms. What do you think of 3/4 inch pipe with that many bathrooms? Thanks in advance for your help. Brian

Brian,
What do I think?
I think he's not a plumber.
The sizing chart link below should help.
The UPC plumbing code would only allow 3/4" on a one bath home.
The length of the pipes from the meter to the farthest outlet make a difference too.
I've used a 1.5" water service pipe for a three bath house with 250 feet of developed length with good results.
The existing 3/4" copper line it replaced was a joke.

• Water pipe sizing