Every sewer line repair job contains an element of the unknown. Because work is done below ground, surprises inevitably occur once the site is accessed—and some surprises are bigger than others. In New Jersey, the Middlesex County Utilities Authority found more than they bargained for when they began repairing part of a 2200-foot-long sewer pipeline in February 2004. Two-thirds of the pipe had deteriorated from microbiologically induced corrosion, discovered during routine maintenance. The repair solution: Sauereisen's Underlayment No. F-120 gunite formulation, because it would enable the pipe to be repaired from the inside, without excavation.