I have a leak at a supply line valve under a bathroom sink. I've read through several "suggested" posts, but it appears every leak is different. In my case the leak is almost non-noticeable when the valve is fully open, but as soon as I try to shut it off, it that's spaying water everywhere. This valve is original (I think) with house and so is about 25 years old; no other valves have had issues like this

This issue is: 1) very recent; 2) has no obvious cause, e.g. it wasn't jostled by something or pipes frozen or anything; 3) no other valves, e.g. the one next to it, are showing any similar signs.

It seems clear it is not the supply line or connections that's at issue. Mostly I am just trying to understand if I should replace the whole valve, or if symptom might be indicating something simpler.

Other than that, if it is a failed valve, any thoughts as to what might have caused it...just time? If just age, should I replace both, and others in my house on a preventative basis?

30-second video of what happens when I try to close valve: My Leaky Valve

1 Answer 1


That is typical of a valve stem packing leak.

It's a typical old-age failure (maintenance issue) for a stop valve of the screw actuated type, since they are rarely operated and the old packing can become hardened and stiff and then fails to seal when you finally use the valve a few decades later.

You can either repack the valve stem, or replace the valve. In some cases you only need to tighten the packing nut around the valve stem a little bit. Yours appears to be likely past that point, based on the volume of the leak unless someone actually loosened the packing nut by mistake.

Many people, myself included, prefer 1/4-turn ball valves for shutoffs, as they are generally less prone to jamming and leaks on the rare occasions that they need to be used.

However, repacking the valve stem is definitely less costly, and may work. It simply requires turning the water off upstream, removing the handle and packing nut, removing the old packing, winding on new packing, and re-tightening the packing nut, then turning water back on and checking for leaks, possibly with some more tightening of the packing nut. You don't want to over-tighten the packing nut, as then the valve becomes hard to operate. It should be tight enough to stop leaking around the valve stem, and not much more.

If repacking the valve stem, it may be worth going a bit further and also replace the sealing washer inside the valve (what shuts off the water) as it's probably also old and hardened.

  • 1
    If you replace valves (my personal preference), do both at the same time. Consider doing the supply lines as well… they’re cheap and you’re already stuck under there anyway. Feb 11, 2023 at 16:36
  • Thanks (both). The valves I have are clearly "builder-grade", and I'll replace (both) with a 1/4 turn style per recommendations. Any manufacturer(s) I should be looking at in particular? Or avoiding?
    – AA040371
    Feb 11, 2023 at 17:26
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    Also, those are BrassCraft valves (at least the left one, right likely similar, if not same), and you can get repair kits for those pretty easily and cheaply: homedepot.com/p/…. They're pretty much plug-n-play.
    – Huesmann
    Feb 11, 2023 at 20:58
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    Having lived in this house 26 years now I quite some time ago developed a policy that I would not touch the old valves--every one has failed when called upon so I simply assume step #1 is to replace the valve with a quarter turn one. Feb 12, 2023 at 5:50
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    @mblatz01 good opportunity/reminder to check on your main shutoff so you don't end up like my parents: the shutoff seized, and then the "city-side" shutoff sheared off at the stem, so they were showering at the gym for a couple days before the city came out and fixed things.
    – mbrig
    Feb 12, 2023 at 7:05

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