I simply installed a JG Y connector & 2 shut off valves downstream of the RO membrane. Close the valve on the line to the DI stage, open the other valve & fill a standard 5 gal water bottle with the line from the RO membrane. Use it for cooking, drinking, making beer/wine etc. I pretty much always wait until I've filled the 5 gal container with RO water before producing DI water. This ensures the TDS out of the membrane has plenty of time to get as low as possible & stabilize. During the summer I generally get 1 TDS out of the membrane, but during the winter with colder water I often get a 0 TDS reading out of the RO. I figure this routine has probably lengthened the life of my DI media.
As far as tying into the water supply, I added a copper tee & ball valve into the cold water line to my washing machine. Reduced & adapted to the RODI size tubing using some JG type parts from Can Tire. Here's a photo;
