One of the solutions being used on an increasing level by our nation's water systems to correct the problem of internal corrosion or tuberculation of older cast iron and steel water mains is cleaning and cement mortar lining in place. There are many economical and operational advantages to cleaning and cement mortar linings as a means of rehabilitating water mains of adequate size and strength in a distribution system. Two distinct advantages are: 1) it extends the useful life of water mains, and 2) it results in a cost savings which normally ranges from 60 to 70 percent of the cost of replacement. A discussion of the rehabilitation process is given.