R/O unit install under sink questions

[plumby]

Hi all,

Just want to state how glad I am that forums like this exist for the DIY or those looking to save a bit
on money out there on easy to do plumbing tasks.

In my recently purchased house I was about to install a RO system under my kitchen sink when I started
wondering if I may be taking a bigger bite than I can chew with how everything is currently setup.

I was planning to use a stainless feed water adapter on the cold water side to feed the RO unit, but had
concerns with the amount of rust I was seeing on the fittings as well as the feed hose.

This is the feed water adapter I purchased: Frizzlife 1/2" and 3/8" Brass Feed Water Adapter - 3/8" Comp with 1/2" Converter Fitting and 1/4 inch OD Compression Angle Stop Valve Adapter for Reverse Osmosis Water Filters, Coffee Brewers - - Amazon.com

To my uninformed interpretation the setup of everything seems unusual.
The cold water is being split off to the outdoor faucet, dishwasher, refrigerator, and kitchen faucet.

Does anyone see anything of concern here that would throw a wrench into my plans?
Should I purchase new supply hoses? I am worried about messing up the copper side of the supply line.

I am tempted to just have a plumber come in to check how everything is plumbed as the setup looks weird.

Also...the black piece of pvc that comes out of the wall to a downward bend, and up. Is that a water hammer arrester?

I have attached pictures to this post.


Thank you for your knowledge/time!

 

[JG plumbing]

Yeah man your plumbing is all methed up. The pvc is a trap not a hammer arrestor. But the drain setup is bad.

I would buy new supply hoses for sure. I wonder if there was bleach with the cap off under that sink at one time, causing all of that corrosion.

Depending on how much time you want to spend and how much you care there is a decent amount of work to do under there. I don't think I would do anything about the 1/2" copper supply line supplying too many things. Really just the hose bibb should have its own branch.

 

[Twowaxhack]

You have one of the best faucets ever made on that sink. Very repairable and reliable. Delta single lever.

You have an illegal trap configuration and you’ve created a corrosive atmosphere under the sink that has attacked the metal.

I would advise you to at least correct the ptrap and replace the flex lines.

It wouldn’t be a bad idea to replace all the stop valves and clean all those connections up.