There are hot and cold shut off valves for our washing machine. The hot one has been harder to turn for some time now. I finally looked closely at the two valves and noticed a fair amount of crud on the hot one as shown in the photo.

What is going on here? Is there potential for imminent failure of the valve?

Thanks. Hot and Cold Valves

  • Use vinegar and let it work
    – Traveler
    Commented Jan 16, 2023 at 1:02
  • Is it rusting? Maybe it's getting more condensation because of warming up and then cooling down. Perhaps it's leaking. Commented Jan 16, 2023 at 1:03
  • Those valves are terrible design to begin with. The cup design is a moisture trap.
    – Traveler
    Commented Jan 16, 2023 at 1:09
  • @Ruskes maybe the handles are installed upside down
    – jsotola
    Commented Jan 16, 2023 at 5:34
  • Heat increases entropy universally. The expansion/contraction cycles caused by every warm/hot load of laundry probably don't help either. Hot water is also thinner, able to fit into gaps that denser cold water can't. In short, the life of a hot water valve is much tougher.
    – dandavis
    Commented Jan 16, 2023 at 6:02

1 Answer 1


It could be sweating or/and galvanic current.

The thin orange/red plastic coating on the hot one is almost gone probably accelerated by heat.

Get ready to replace with nice new Quarter turn valves.

  • 1
    +1 for suggesting quarter-turn valves. Unless you're doing something funky like barely opening the valve to get a tiny stream, there is no reason not to replace compression valves with quarter-turn!
    – DoxyLover
    Commented Jan 16, 2023 at 3:49
  • How urgent is this to do? Would a failure be catastrophic or small drips? And can you provide a link to a suitable replacement? Seems like something I could do - just shut off the main water valve, drain the pipes, attach tape to threads and screw it in. Commented Jan 16, 2023 at 13:48
  • Yes, @Not_Einstein, failure would be small drips or catastrophic. Depends on how it fails. Most likely, it would drip first. Since you have a basic understanding of the replacement process, it's most likely you could execute the replacement yourself, as well. If you have specific question(s) on the process, please ask a whole new question.
    – FreeMan
    Commented Jan 16, 2023 at 16:32
  • Just for clarification - normally the water is directly connected to the washing machine which has its own shutoff valve but as failure of these would cause flooding, the external shutoff valves in the photo were added. If the external valve fails, does that mean it would just pass water along, which the washing machine valve would stop, or does it mean water would shoot out from it? Also, there are different size valves (1/2", 3/4", etc.). Do I get a valve with 3/4" garden hose type connections? Commented Jan 17, 2023 at 0:06
  • @Not_Einstein, it could have exterior leak, thus flooding the area, it could get stuck in closed position so washing machine will get noting. it could get stuck in open position, at which time you need to worry about washing machine valve working. When transitioning from solid pipe to rubber hose it is advisable to use a valve, since the rubber hoses are not reliable. You need 3/4 hose valve. The main reason for replacing it since you said the hot water valve is hard to operate, indication of coming failure.
    – Traveler
    Commented Jan 17, 2023 at 0:16

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