Looks like a John Guest connection. It's a push in design and VERY reliable.

Google how John Guest fittings work

It would help if you mentioned WHERE the leak is... is it leaking where the tubing goes in?

There's an o-ring inside and you release the tubing by pushing the collar towards the connector and the tubing will slide out.

Make sure there's no barbs or nicks in the tubing and the end needs to be cut square. Use a razor blade. If it still leaks then the o-ring is nicked and the connector has to be replaced.

Is it leaking where the fitting screws on the tank? Remove the fitting, clean the threads, and apply teflon tape in the correct direction and screw the fitting back on the tank.

This post was edited by justalurker on Thu, Feb 21, 13 at 0:07

Seems to be leaking from where the collar is. Thanks for the tip on how to release the tubing. I had pulled on it many differnet ways to get it to come out. I'll replace the tubing and perhaps the connection. It is at my parent's house, about 10 years old. Has not leaked much since the wooden cabinet only has a small stain on the formica.

I have something like this on a filter system. It leaked at the collar. It seemed to be sensitive to the angle of the line coming in. Perhaps if you straightened the incoming line (more vertical) it would stop leaking.

Thanks for the advice. I have ordered new connections. I was going to change the PE tubes too but apparently the blue tube is permanently attached to the aucet. I'd have to buy a new faucet to change the tube!?!. I'll just trim 1/4" of tube and install the new connections...