1. Combine all three cheeses and salt in a medium bowl. Rinse ziti under cold water in a colander, allowing some water to cling to pasta.
2. Mist inside of slow cooker with cooking spray. Place half of pasta in an even layer over bottom of cooker. Spoon half of sauce over pasta. Dot with half of cheese mixture and half of basil. Repeat with remaining pasta, sauce, cheese and basil. Pour in 2/3 cup water.
3. Cover and cook on high until pasta is tender, 2 to 3 hours.