(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 3 of 3

Thread: Installing sprinkler shut off valve below frostline

  1. #1
    DIY Junior Member Tubal's Avatar
    Join Date
    Apr 2012
    Salt Lake City, Utah

    Default Installing sprinkler shut off valve below frostline

    Hi all.

    I'm attempting to put in a sprinkler system in Northern Utah where the frost line is approx. 36" below ground.

    The house is around 30 years old, and at one time there was another sprinkler system in place by the previous owner, but it has long since eroded so I'm basically starting from scratch.

    The water main comes in to the house and is buried about 36" below ground. The old owner had his sprinkler system tied into this main about a foot back from the house, and all that was remaining was a plugged 3/4" tee. So that is my water source.

    I've dug down to the tee, and attached some pvc to run up to ground level with a ball valve as my sprinkler shutoff valve, and that's where I'm at now.

    I'm thinking that this isn't going to work, because it will freeze and break in the winter. Am I correct in assuming that, and if so, is there a way to keep this from happening? Could I put the shutoff valve in a valve box 12" below ground, or would I need to install a valve 3' below ground? How is this normally done?

    Thanks for any help.

    Name:  sprinkler.jpg
Views: 833
Size:  13.6 KB

  2. #2
    irrigation tech. mike1059's Avatar
    Join Date
    Jun 2011
    Portland, OR


    although I'm unfamiliar with the codes in your area, it's best if a shut-off valve and backflow preventer are installed at 36" inside a valve box for access then bring your line up to 12" for your electric valves and station lines.

  3. #3
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Yakima WA


    The backflow preventer must be certified annually, so you don't want it 36" below the the surface. My supply line is 5 feet deep. The irrigation side tees there and goes into a Muller stop and waste valve. Then it come to just below the surface and is connected the the BFP. From the BFP, it goes about 30 feet toward the house when the manifold with the zone valves are located. The controller is in the basement just opposite the manifold. I remove the BFP in the winter just to make certain there is zero change of a little water freezing and breaking it. You have to have the correct type of BFP to mount it below ground level, but they do exist. Your local area may or may not abide by Federal laws pertaining to inspections, but it should certified as functioning properly each spring. Mine is scheduled this week.

Similar Threads

  1. Replies: 17
    Last Post: 10-28-2010, 07:37 PM
  2. Help installing shut off valve on copper pipe
    By jewelryLady in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 4
    Last Post: 09-21-2009, 11:13 PM
  3. Installing Toilet shut off valve
    By theragirl in forum Toilet Forum discussions
    Replies: 1
    Last Post: 07-14-2008, 11:38 AM
  4. Installing Shut Off Valve on copper pipes
    By flicker55 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 08-04-2007, 05:05 AM
  5. Installing shut-off valve in main line
    By j.bowersmd in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 2
    Last Post: 02-28-2006, 07:28 AM


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts