We're preparing to replace our bathroom faucet. We were able to easily disconnect the cold water supply line from the shutoff valve to the faucet by simply loosening the nuts holding it in place. However, when we went to disconnect the hot water supply line, we see that it appears to be built in to the water shut-off valve. We are both new to home improvement, but have done a lot of research and haven't come across anything like this before. What IS this? Is our only option to replace the water shut-off valve entirely?

image of our shut-off valve

(Our new faucet has 3/8" water supply lines, otherwise we could reuse the existing supply lines and not worry about the weird shut-off valve)

1 Answer 1


I've dealt with these before. The flex pipe is silver soldered into the valve body, probably a product design of the day to dispense with having a problematic compression fitting that would eventually leak.

If you loosen the nut from the pipe nipple, the valve body and flex supply line pipe will be rotatable to position it for a direct lineup to the faucet inlet.

enter image description here

Even if the other end of the metal flex supply line is compatible with the faucet (sounds like it isn't), brass and copper flex work harden from bending into position and can crack if disturbed for later repairs, so I don't recommend reusing it. The only way to fix this is to replace the shutoff valve with a 1/2" to 3/8" right angle shutoff. The newer ones available are nice quarter turn units. Remove the compression fitting nut and ferrule and the 3/8" supply line should thread right on. They use a neoprene flat washer now that gets rid of the leak problem the original silver-soldered supply line was meant to prevent.

enter image description here

  • Hmm, we replaced the shutoff valve with a 1/4 turn 1/2" - 3/8" shutoff valve. We left the original nut and ferrule in place. We think we've tightened the nut as far as it will go, but there's still a very slight drip. Does this mean we have to cut off the pipe to replace the compression fitting? Commented Nov 10, 2013 at 2:47
  • Yes, if you have enough length to do it. Ferrule fittings must only be tightened just enough to compress the ferrule so it seals. It's easy to over-tighten them the first time around which leaves no further room for added compression the next time the connection is taken apart. I do not use ferrule type fittings anymore. The new steel braid flex supply lines are made to length, have built in flat washers that seal much better. Measure the length from faucet inlet to shutoff outlet with a steel tape measure, flexing it to reflect any bends needed to get it up top and add an inch. Commented Nov 11, 2013 at 1:11

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