I'm replacing my kitchen faucet and the new faucet has 3/8" fittings on the hot/cold hoses, but the shutoff valves have 1/2" openings. Would it be better to replace the shutoff valves, or find an adapter like this?


In this case it would be a lot better to just replace the shut off valves, by adding an adapter you are just adding one more thing to break or go wrong and cause leaks! -7 years plumbing experience and red seal certified (Canada)

  • One problem I foresee, and I need to confirm, is that the dishwasher might also have a 1/2" opening. So even if I were to replace the shutoff valves, I'd have to put an adapter on the new one for the dishwasher -- unless there's such a thing as a 3-way shutoff valve with a 3/8" and 1/2"? – Matt Mar 25 '15 at 5:49
  • Do you have a picture of thee current set up? I would recommend having your cold go directly to the tap with the new valve on it and then have your hot come up, have a tee with the valve on top to go to your sink and then a short piece of pipe coming out of the side of that tee to go to your dishwasher valve and this to your dishwasher, this could easily be done with copper and/or plastic depending on yor current set up – Mark Shaw Mar 25 '15 at 5:51
  • Would you recommend replacing the compression ring and nut, or use the same one if I can? – Matt Mar 26 '15 at 5:40
  • I would recommend replacing it, they usually stretch over time and this could lead to leaks – Mark Shaw Mar 26 '15 at 17:10
  • I replaced the valves entirely but wound up with a small leak behind each new nut (pics: imgur.com/a/xPou8 ). The drip shown is after leaving the water running on high for a few minutes to test. I've tightened each nut as much as I can manage -- is there any way to correct it other than pulling off the valves again? – Matt Mar 27 '15 at 3:02

Use the adapter. Why go through all the trouble of installing a new shutoff, if you don't have to.

If you're using any fittings that have rubber washers, don't over tighten them. The washer could be crushed, deformed, or pushed out of the way.

  • FIP to compression fittings are in no way wrong. You have to make the reduction somewhere. There are not any rubber parts on the fitting from the link. I would not use rubber washer fittings, they are temporary. You want compression fittings to deform a bit. So if there are rubber parts, that I do not see, go with tester101's answer – Some Guy Mar 25 '15 at 23:40

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