Calleguas Municipal Water District experienced a failure in 140 ft of steel liner within a 78 in. dia. prestressed concrete cylinder pipe (PCCP) water main. The failure resulted in local flooding and loss of service. SGH was retained to evaluate the safety of the as-constructed steel liner. We performed a nonlinear finite element analyses of the 3/8 in. welded steel liner to reconstruct the failure and evaluated several reinforcing schemes.