Trim any excess fat from the pork roast. Rub 2 packets of Old El Paso Mild Taco Seasoning all over the roast, and place it in a 5 to 6-quart slow cooker. Pour ½ cup of water around the bottom of the roast and cover.
Cook on low for 8 to 12 hours, or overnight. Turn off the slow cooker and allow the roast to rest for about 30 minutes. Shred the meat with a fork, removing as much remaining fat as possible. Put the meat back into the juices in the slow cooker and keep on warm for at least one more hour, or until ready to serve.