Replacing galvanized pipes for entire house

[vlepouce]

Had a few questions. My house is about 65 years old and has galvanized water supply lines. Loosing pressure and crap breaking loose in the pipes is causing pressure drops. I have a 5/8" meter and the original supply from line 3/4 inch where it splits to feed water heater and rest of house. At the split it drops to 1/2" to feed water heater and the rest of the house. Outlets for fixtures are 3/8". Looking to replace everything with PEX. Thinking of doing 1" from meter to manifold where cold would have a loop for the supply. There are 2 outside hose bibs that would come off the manifold with 3/4" and a 3/4" to feed water heater. The hose bibs would get reduced to 1/2" before connecting. My thought was to run a separate 1/2" line for each fixture, kitchen faucet, dishwasher, bathroom sink, shower, washer, etc.. and then either make the stop valves 1/2" or 3/8". Run 3/4" PEX from water heater to manifold and then run to each fixture in 1/2", stop valve in 1/2" or 3/8" to match cold.

Two major questions, Waste of time to run 1" from meter to cold water manifold loop?

What size is advisable for fixtures, shower is currently in copper and 1/2" to fixture.

Want to get to where more than one fixture can be ran without loosing water pressure.

 

[Helper Dave]

What size is your supply before the meter? Unless it's 1" or larger, it wouldn't benefit you to upsize to 1" just to run to a manifold.

As for fixtures, 1/2" is good to most everything, unless you want more volume. If you're going for a "car wash" type shower set-up, for instance, with lots of heads and sprayers, going to 3/4" would be better. They make 3/4" valves. Also, if you want to run 3/4" to your hose bibs, might as well use 3/4" hose bibs--not much reason to reduce there.

And just use the standard 1/2" to 3/8" mip stops at the fixtures. No reason to change pipe size.

The only thing I'm not super familiar with on manifolds is what to run to a toilet (my company only does trunk and branch). You always want 3/4" just before the toilet with PEX, because of the smaller ID. Maybe someone with more experience with manifolds can chime in, but I'd guess you'd want the run to toilets be 3/4" before reducing down on the stub-out.

If you have a tub spout, keep in mind you have to run copper, not PEX, from the valve down to it.

And getting rid of all that galvanized should solve your water pressure problems. Those pipes are seeing the end of their usefulness right about now. Good luck with the conversion.

 

[vlepouce]

What size is your supply before the meter? Unless it's 1" or larger, it wouldn't benefit you to upsize to 1" just to run to a manifold.

As for fixtures, 1/2" is good to most everything, unless you want more volume. If you're going for a "car wash" type shower set-up, for instance, with lots of heads and sprayers, going to 3/4" would be better. They make 3/4" valves. Also, if you want to run 3/4" to your hose bibs, might as well use 3/4" hose bibs--not much reason to reduce there.

And just use the standard 1/2" to 3/8" mip stops at the fixtures. No reason to change pipe size.

The only thing I'm not super familiar with on manifolds is what to run to a toilet (my company only does trunk and branch). You always want 3/4" just before the toilet with PEX, because of the smaller ID. Maybe someone with more experience with manifolds can chime in, but I'd guess you'd want the run to toilets be 3/4" before reducing down on the stub-out.

If you have a tub spout, keep in mind you have to run copper, not PEX, from the valve down to it.

And getting rid of all that galvanized should solve your water pressure problems. Those pipes are seeing the end of their usefulness right about now. Good luck with the conversion.

Thanks for the reply! The line coming into the meter appears to be 3/4" with a 5/8" meter. I thought about the 1" with the idea that if the outside supply line had to be replaced, would request a bigger supply coming to the house. The other reason was because I would have to put 3 elbows in to get it up to ceiling and cross the basement.

The current toilet connection is 1/2 with a 3/8 reducer to a 1/4 turn valve. I replaced the shower a couple of years ago and it is all in copper for about 7 feet, then a dielectric unions back to the galvanized. Currently the dish washer and the sink share a single connection for hw and the same pipe has branches to supply the bathroom sink and the toilet. Was thinking about running 3 separate lines in 1/2" to each fixture instead of splitting them off one line.

Still deciding on putting pex up into the wall or copper piping in the walls and PEX in the basement. Will be using the copper ring crimps on all connection. I don't like the idea of push to connect fittings, especially in a wall.

Still in the planning stages, but have started assembling the tools and some of the piping.

Thank you for your time and consideration in answering, want to do this right and do it once.

Vic Lepouce