So I got a new kitchen sink, and I'm going to be replumbing the drain pipes, and while I was down there I noticed my hot water line is all corroded. Especially the T that goes off to my dishwasher. I'd like to replace both that T, and the valves that go to my sink and dishwasher. However, as you can see in the picture, the water line coming up from under the cabinet doesn't have much pipe to work with. If I cut that pipe off below the fitting, I won't really be able to get another fitting in there.

I haven't done much plumbing at all, but am pretty handy in most other areas, so I figured I could handle this. But not sure. I was just going to use sharkbite push fittings for this, but now I'm not sure.

Any tips on how to go about this?

The line going up goes to the faucet, the one to the left goes to the dishwasher.

 

The corrosion you are seeing is on the outside of the fitting. It is likely caused by spills in the cabinet or water leaking down from the faucet above. You can even see the residue on the PEX tubing where stuff (water, cleaners...) has left a trail. I would not replace the fitting. Wipe off if the residue and corrosion bothers you.

Is you dishwasher shutoff leaking or doesn't shut off completely in the closed position? Why do you want to replace it? I would not replace it if it is working properly.

Have you tried pulling up on the pipe where it comes through the cabinet base? Usually there is slack and more pipe down below. Still, you don't want to replace things that don't need replacing as there is a limited amount of pipe to work with. You can also remove fittings and not loose any pipe length by VERY carefully cutting the copper crimp ring off. It is very important that you do not nick or damage the tubing while doing it though.

 

Ok well that's good to know. The dishwasher shutoff valve is not leaking that I know of, it was just recommended by a plumber friend who saw a photo of my drains I sent him, trying to plan the drain. And yes, you're right. I did just try pulling up on the pipe, and there is a bit more pipe to play with there. But perhaps I will just leave those valves for now, and worry about replacing them later if there are any problems. There is some slight water damage around that area, but it doesn't ever seem like there is water actively there. And I have had a water sensor alarm down there for over a year, and it's never tripped. So if there is a leak, it is small enough that it evaporates before it can build up lol. Thanks for the advice!

Maybe I can switch topics from those valves to the drain? I can start another thread on this if needed, but it's the plumbing for the same project.

I am going from a double basin sink, to a single basin with a garbage disposal. Kind of wondering if I should just cut the middle out of the long horizontal pipe it's currently connected to and move it over to the middle, then just cap off the upper pipe? Or if I should cap off the lower one and reroute the disposal to the upper pipe? It seems like if I did that, the p-trap should still be lower than the disposal drain line, but not entirely sure. I could also just cut out the whole drain assembly and build it from scratch. Here is a pic:

 

I agree.... leave the water line as it is. It's all plastic. No leaks - no worry.

I'd cap off the upper trap and use the lower one.
It would be easy to just cut a piece out where the red lines are and then use a coupling to reconnect them.

 

Cool, that was my original thought. Thanks!

 

I myself would use the right side trap fpr the new disposal location. No mods required.

I would cut the lower one and make it a clean out. Glue a clean out cap on the arm about where PJ marked..

 

The PEX crimp rings are copper. The "corrosion" is actually verdigris which is a natural patina that forms on copper.

 

So I got to doing this this morning, and was planning on trying to use the right side upper drain, and turning the lower one into a cleanout. However, and I started to dry fit everything, disposal up on blocks in about the right position, I realized that the disposal drain would not be higher than the actual drain, so I think that wouldn't be optimal. But then I realized, to use the lower drain I really don't have to cut/shorten it at all. I just turned the disposal so the drains are on the left side, and swiveled the p-trap over to meet it. Is there any reason I can't configure it like this? Water has to make a bit of a u-turn, is that a problem?


Sorry this is the best shot I could get.

Edit: yeah I realize I don't have the threaded ring in the disposal yet. Just a dry fit.

 

That idea should work fine.

Be sure to fasten the dishwasher line up high under the countertop.

 

Thanks, it worked out pretty well, all done. So do you suspend the dishwasher drain up high like that to prevent the sink from draining water back to the dishwasher?

 

Yes. Hanging the hose up high acts like a trap.