Adding a second water main shutoff 10' away

[Andrew Schrader]

Hello everyone,

I'd like to add a second main water shutoff valve about 10' away from the existing. It's a duplex so I'd like water shutoff access on both sides. So I want to cut in above the existing water shutoff valve, which is 3/4" copper. Run 10' of 3/4" PEX to an accessible location with a valve then run 10' of 3/4" PEX back to the water line that feeds the house.

Will this additional pressure drop be noticeable in my house fixtures? Or cause any other issues?

Thanks,
Andrew

 

[Reach4]

You want each unit to be able to shut off its own water, or you want either valve to shut off both units? Or yours shuts off both, and the new valve only shuts off the other unit?

I would think you might want two new valves -- one for each unit.

If you get full-flow ball valves, the valves themselves should not have noticable pressure drop. The new 3/4 pex elbows and tees can have an effect. Also, not all pex fittings are the same. The cheaper pex and fittings have more drop than the F1960 expansion fittings, but that needs PEX A pipe. In the type that uses crimps or clamps, plastic fittings have more drop than brass fittings.

If you have a tee, the straight path gets less drop for a given flow. Feed the neighbors from the side port.

 

[Sponsor]

 

[wwhitney]

If you have 3/4" copper but want to use PEX for the new work, then 1" PEX might be a better choice than 3/4" PEX. I think of PEX as being roughly 1/8" smaller when comparing it to copper in terms of its inner diameter and resistance to flow.

Cheers, Wayne