I'm planning to install a "point of use" water filter system. It's the kind that's normally mounted under the kitchen sink. The filter unit accepts 1/4" LLDPE plastic tubing. It's similar to the stuff that's often used to supply refrigerator icemakers, but slightly superior. (If anyone can tell me exactly how it's superior, I'd really like to know.)

These water filters are usually mounter under the kitchen sink. We don't have room under there so I plan to mount ours in the basement. It's still technically under the kitchen sink!

The complication is that I can't use the normal procedure to tap into the water supply. Normally, a special tee (plastic!) is screwed onto the output of an angle stop. It provides a pass though for the displaced faucet supply line and also a 1/4" tubing connection for the filter.

We have a Zero Tolerance Policy for water leaks in our house. We've dealt with two defective icemaker hookups over the years. (None were done by me!) We don't want another water incident. I've become very picky about having every bit of plumbing "done right" above all else.

Here are the options I've come up with so far:

Option #1 - The Lame Duck
Use the same funky 3/8" angle stop adapter that everyone else uses on these filters. Install it under the sink and fish the supply tubing down to the basement and into the filter.

This approach highly unappealing. I don't trust the adapters and I don't like idea of the supply being in a different room from the filter. If that plastic adapter breaks my kitchen is flooded.

Option #2 - The Elegant Solution
Tee off the 1/2" copper. Install a copper sweat ball value for shutoff. Install a sweat copper to 1/4" NPT Female adapter. Screw in a John Guest 1/4" NPT Male to 1/4" tubing "stem" fitting. Done.

Here's the John Guest part:


Are 1/2" copper sweat to 1/4" NPT Female adapter available at the local big box? I've read about them but never seen one on the shelf.

Option #3 - The Less Elegant Solution
This one is exactly like #2 except that I would substitute a 1/2" copper to 3/8" NPT Female adapter followed by a similar John Guest fitting in 3/8". I would then use a John Guest reducer to get from 3/8" tubing to 1/4" tubing. Done.

The only way this makes sense over #2 is if I can't find a 1/2" sweat copper to 1/4" NPT Female adapter in the local stores.

Option #4 - The Angle Stop Solution
Tee off the copper. Install an angle stop with 1/4" compression output. (I don't know if I can find that locally. I've seen them in the Watts catalog.) Attach tubing. Done

Option #5 - The Icemaker Kit Solution /w Ball Valve
Tee off the copper. Install a copper sweat ball value for shutoff. Sweat on a short capped stub. Pop a saddle valve with 1/4" compression output onto the stub. Attach tubing. Done.

Option #6 - The Icemaker Kit Solution
Randomly vampire a saddle valve onto the closest piece of cold supply line. Attach tubing. Done.

Which is the most professional and leak free over the long haul?

Are there any other good ways to do it?

I have one ancillary question regarding connection of tubing to compression fittings. No matter which supply strategy I choose I'll still have at least two transitions from 1/4" tubing to 1/4" compression on the delivery side: one at the faucet and the other at the icemaker.

A few companies make adapters that screw onto 1/4" compression fittings and provide a 1/4" tubing push-to-connect on the other side. They call them "faucet connections" or "7/16-24 UNS Female to 1/4" tube fittings".

Here's one example:


Should I use those for all of my compression to tubing junctions or should I go with standard compression joints (nut + plastic ferrule)?

Both of our previous water damage incidents were due to leaks in poly tube compression fittings. Our refrigerator's water input even has a warning against connecting plastic tubing to its brass compression inlet.

The John Guest compression adapters are expensive and very difficult to source. is it worthwhile to use them rather than standard compression joints?

(The one I linked to above is made of acetal. I need to find the same fitting in polypropylene.)

Thanks much if you've read this far. I really need the advice. I've been spinning my wheels on this project for too long.