Hi,
My question is about pipe diameters and how it affects available water in the home. I will be replacing the last 35 feet of an existing 1200 foot supply line. The supply line is 1” diameter but at the end it connects to a 3/4" pipe that goes into the home through the foundation.

Rather than using 35 feet of new 1” pipe followed by a 1” x ¾” coupling at the foundation, I would prefer to put the 1” x ¾” coupling at the beginning of the new section and use 35 feet of 3/4" pipe.

Given that the pipe going into the foundation is 3/4", will using the second method substantially reduce available water into the home?

YOur 1200 feet of 1: pipe will already do a good job of reducing the volume and dynamic pressure of the water.

I would stub 1” into the house then reduce to 3/4

HJ: So, is your conclusion that the 35 feet of 3/4" won't affect the situation much or that it will?
p.s. with the existing line (1235 feet of 1" ) the house has adequate water flow and 50 psi (measured at a hose bib).



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Thanks bsipps; this is an existing system. The pipe going into the house's foundation is 3/4" so I have no control over that. I only have control over the 35' section of supply line that I will be replacing (which I'd like to be 3/4" if it does not substantially affect the water usage in the house).

What type of pipe is the 1" and what type of 3/4" are you wanting to install? What type is the 3/4" through the foundation?

Depending on the available pressure at the 'street end' a change from 1" to 3/4" probably WILL introduce an unacceptable level of friction loss and subsequent reduction in total 'flow rate' volume.

IMO, keep it at 1" - it was done for a reason.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Its effect will be minimal. The pressure at the hose bibb is immaterial, unless you are measuring it while a faucet is running,

Unless the OP has minimal main pressure to start with.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Steve, the supply line is pvc, the 3/4" into the foundation is copper. I haven't decided what type to use for the 35 foot replacement yet. Thanks!

hj: thanks for your input and your tip about measuring pressure.



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bernabeu: thanks for the input.

. deleted

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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REgardless of the "main pressure", 1200 feet of 1" anything will destroy the dynamic pressure, AND, inertia can cause a reverse water hammer any time they use a quick opening valve.

oops


missed the 1200' aspect


yeah, i agree, the last 35' before the house matters little, if at all


(@ hj - the world may now come to an end)

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

To CSCJJD: Starting with 50 PSI at the meter will limit you and 900 feet of pipe will cause a lot of friction loss and volume will suffer because of that. Ideally start with 1 1/4" at the meter so you can get more volume to your home. Really it depends on what your purpose for the water is. IE Irrigation, fire protection, etc.



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