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New Member


Friday, April 3rd 2009, 11:55pm

Valve prior to backflow preventer

I am in the Nashville area so my system needs to be winterized. Sorry this may seem like a stupid question but I want to make sure I understand this part.

My meter and main shutoff are at the road. The main line then runs into my crawl space. I was planning on tapping into the main line just before it goes through the brick wall into my crawl space. After the tee (I place into the main line) going to the backflow preventer I realize I need to put in a shut off valve. Does this shutoff valve need to be underground next to the mainline or can it be next to the backflow preventer 12 inches above the ground.

In the winter I am planning on removing the backflow preventer but I was curious about the shut off valve. Does the valve just have a 18 inch shutoff handle so I can turn it off from above ground? Does the valve not really matter if it is above ground because it is a metal valve and when it closes there is essentially no water in the valve and if ice forms below the valve it just pushes down toward the main line where the water melts it. I hope you can understand what I am trying to ask. Thanks


Supreme Member


Sunday, April 5th 2009, 7:26am

I believe that at a minimum, the valve must be "at depth" so that the water before the valve can not freeze.


Supreme Member

Posts: 5,376

Location: Metro NYC


Sunday, April 5th 2009, 12:29pm

If you have plumbing in the crawl space, why not put the system shutoff in there? With above-ground backflow preventers, you'd want to exit a foundation above grade if possible.


New Member


Tuesday, April 7th 2009, 12:05pm

I new I was just over thinking this entire thing. My way of making everything more difficult I guess.

I just need to make sure I rent an impact drill with bits from a tool rental place to make the job easy. I drilled a whole with my regular drill and a concrete bit through the foundation for an outside water spicket. I definitely don't want to do it that way again.


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