THE PROBLEM Over a period of years, cast iron and steal pipes develop cast, corrosion and tuberculation within the inside walls increasing roughness, reducing the diameter of the pipe, and producing joint leakage. This has a significant negative impact on the flow capacity of the pipe. In addition, these corrosion processes can increase the possibility of significant leakage and major failures, which can result in the suspension of services and very costly repair work. THE SOLUTION The rehabilitation of pipes using a cement mortar lining system restores the flow capacity by creating a smooth surface on the interior walls of the pipes, which results in a significant increase of the Hazen-Williams coefficient. This system will also stop the corrosion process after creating a chemical shield on the surface of the pipes, which prevents future corrosion and tuberculation. Cement mortar lining allows you long-term enjoyment of a number of benefits including: reduced maintenance costs, complete elimination of all problems usually associated with cast iron and steel pipes, but most importantly the permanent maintenance of good flow capacity. Frequently, pipe maintenance is done through the use of a technique called drag. This system increases flow capacity but does not address the causes of the initial corrosion and tuberculation. If a pipe is cleaned using only this system, the corrosion process begins again immediately and sometimes at a faster rate. Maintenance with cement-mortar lining protects the pipes against future corrosion and will surely improve the Hazen-Williams coefficient. In addition, cement-mortar lining is a secure investment, as can be seen in sites around the world where there is no sign of aging and corrosion even after 30 or 40 years. It is also important to note that water services are maintained during repair projects and water services are interrupted only to install bypasses that correspond to the section that will be repaired. This way the inconveniences for users are minimal. There are even more benefits from cement-mortar lining such as: the elimination of leaks, the reduction of pumping costs, and the improvement of water quality. THE PROCESS The repair and maintenance process will include: a) Cleaning of the surface of the pipe to prepare it for cement-mortar lining. The cleaning is done with steel scrapers that eliminate all tuberculation and with rubber sweeps that eliminate debris and water. In pipes of 1.10m of diameter this process may be done manually. b) Lining of the interior walls of the pipe with layers of cement-mortar of varying thickness from 6 to 18mm per layer. The layers are applied using a high-pressure centrifugal system that moves at a synchronized speed to ensure that the layers are smooth and even.