RPZA+PRV galvanized pipe exposed loop leaking; need to rebuild!

[Flapper]

Last year I found some minor leaks at that gate valve, but didn't fix it as it would require rebuilding this whole thing.
Today I took a look at it and discovered that it had gotten worse. Now there's a hissing sound, which I thought was coming from the leaking valve until I dug into the ground. Turns out there's a much worse leak in the ground, making a hissing sound and saturating the area.
Also, the RPZ assembly has started leaking from the vent. It did a little while ago but I fixed it (somewhat) by purging it to open the vent. I found it dripping again and it won't stop dripping.
This galvanized pipe loop needs to be rebuilt as soon as possible, from the meter to where it connects to the polyethylene supply line (somewhere underground nearby). We'll get a new PRV but I'd like to reuse the RPZ, though because it's leaking and isn't lead free, we may have to replace it too. And unless strictly prohibited, this must be done ourselves.

Questions:

1. This is a highly critical part--leak is before backflow preventer and PRV; very high pressire (175PSI last I checked). What regulations (in California) apply to this?
2. We may need some kind of temporary bypass until and during the rebuild. Can that be done? Recommendations? (already done)
3. I reckon it is going to have to be remade with copper, but I'd much rather use PVC if I can. What methods are available?
4. What would you do in this situation?

Feed me information!!!

 

[Jadnashua]

Most PVC water pipe doesn't like UV, so not much good above ground.

Putting in a temporary bypass is going to create numerous problems...the safety T&P valve on your water heater will open at 150psi, so it would constantly be gushing water, and the seals in all valves in a home are designed for a max of 80psi...they're tested for higher to provide a safety factor, but 175psi is beyond twice what they're designed for...can you say rupture and flood?

To get this done in a timely fashion, you may have to bite the bullet and pay someone. And, if there's any galvanized piping in the house, you should start budgeting to replace it all...it's a time bomb waiting to fail. As galvanized ages...it can rust from the inside, leaving a very thin shell. Sometimes, it doesn't take much to fracture it. Plus, it can narrow the water passage way down. You may not notice it because you have such high water pressure available that can mask that smaller effective pipe diameter.

If you can afford the time without water...assuming your shutoff works, you can rebuild things after it at your leisure, and yes, with moderate skills, you might be able to do it and pass an inspection. Normally, in plumbing, you have to bring parts you touch up to current codes. As a result, you may not be able to reuse some of the bits. Now, if you could rebuild them in place, you MIGHT be grandfathered, but not when replacing. How CA treats this sort of situation, I do not know. ON some things, they're their own world of requirements.

 

[Sponsor]

 

[Flapper]

A bypass is now in place I'm aware of the pressure issues, and am using a PRV with it

And, if there's any galvanized piping in the house, you should start budgeting to replace it all...it's a time bomb waiting to fail.

I know all about that and it will be replaced when the time comes

Most PVC water pipe doesn't like UV, so not much good above ground.

True, but I could wrap it all with foil tape. At our other house we have a loop with a vacuum breaker, made of PVC and wrapped with tape and it's fine. I'd much rather use PVC if I can.

 

[Jadnashua]

There is PVC pipe that is designed for pressure, just make sure you don't use drainage pipe, which isn't. Personally, I do not have enough experience in that to aid you any more. SOmeone else probably does. I'd be somewhat worried about the more fragile plastic pipe coming up in a loop if you had to replicate the existing arrangement...it's nowhere near as strong as metal. I'd be more inclined to redo it in copper.