Methods, processes and systems for cleaning, coating and sealing leaks in existing pipes, in a single operation. A process can include isolating, draining, drying, cleaning and sealing a piping system. Air can be forced and pulled throughout the piping system by a generator and a vacuum. Pipes can be protected from water corrosion, erosion and electrolysis, extending the life of pipes such as copper, steel, lead, brass, cast iron piping and composite materials. Coatings can be applied to pipes having diameters up to approximately 6″. Leak sealants of at least approximately 4 mils thick can cover insides of pipes, and can include novel mixtures of fillers and epoxy materials, and viscosity levels. A positive pressure can be maintained within the pipes during applications. Piping systems can be returned to service within approximately 96 hours.