I noticed an irrigation control box filling up with water even when the sprinklers and gate valve were off. In order to trace the leak I removed approx 4 inches of dirt to reveal the fittings. I noticed water trickling out from under this round area - I think its called the bonnet? Its the part that is screwed onto the T pipe joint. I tried tightening it which only slowed the leak. This joint has probably been buried under damp soil for years - in fact it moves easily when I attempt to open or close the valve.

Is it possible to get a new valve and replace it to stop the leak? Could it be a rubber washer? I've got a wrench, channel locks, plumbers tape. Here are photos that may help.

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  • "I've got a wrench, channel locks, plumbers tape." A) Good on you for having some basic tools. B) Even better on you for telling us that! If only others would do so...
    – FreeMan
    Commented Jul 1, 2022 at 15:59

2 Answers 2


I would rebuild the valve much easier than replacing and rebuilding is less expensive. I have seen oring and fiber/ gasket material under the “bonnet” a set of washers and some valve stem packing in kits and all are good things to have to rebuild valves like this, my original kit was a metal box it is so old and I have refilled it dozens of times spending very little but saving 10-100x the cost of the parts compared to having it done. The last all around valve rebuild kit I saw at a plumbing & electric specialty store was 20$ it had everything needed for at least 10 rebuilds and if just seats more than 20. I suggest all home owners should have a kit and my kids got them as house warming presents but I still end up doing the rebuilds often.

  • 1
    I buy my kids smoke detectors. Both honorable, though mildly passive aggressive gifts. I'm sure they would prefer sofas. :)
    – jay613
    Commented Jul 1, 2022 at 9:10
  • Thanks for the response, I'll give it a shot this weekend - are replacement or repair kits easily available at stores like HD? And just to be certain, this fix is possible without removing the T joint - just the bit above the bonnet, right?
    – eszed
    Commented Jul 1, 2022 at 14:13
  • @eszed yes, you should be able to find them at a big-box store. If not, any plumbing supply place will have it. There's a chance it'll even be cheaper at the plumbing supply place!
    – FreeMan
    Commented Jul 1, 2022 at 16:05
  • HD didn't have it. Said this was an old style valve. I don't think I'm skilled or courageous enough to replace the entire valve (T joint portion) as there isn't much room to work. I'll try a dedicated plumbing supply store to see if they just have the top portion of the valve. Otherwise I'll try my luck with a compatible washer and teflon tape.
    – eszed
    Commented Jul 2, 2022 at 0:07
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    Update 3: fixed! What I did wrong the first time was try to thread the new bonnet/stem to the joint with the gate closed which meant fewer turns and thereby no seal. While waiting in queue at the store I was fiddling around with the old parts and realized this by chance. I went home immediately and thread the bonnet with the gate fully open this time and lo and behold I got at least 4*360 turns. This stopped the leak. Time to cancel the plumbers appointment.
    – eszed
    Commented Jul 2, 2022 at 21:15

usually it's a fibre washer in that location (not rubber) but it looks like previously someone tried to use teflon tape there.

It looks like it's been wet there for a while. you may need to replace the whole stem assembly.

  • HD said this is an old style valve and they don't carry it. I'm having trouble identifying and naming this style of gate valve. Would any stem replacement kit work? I don't think it's the stem - it leaks even when the valve is off. The bonnet area is loose and isn't gripping the T joint well which leads me to believe it isn't the stem inside.
    – eszed
    Commented Jul 2, 2022 at 0:11

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