A wash system for a gas turbine engine includes a foam generating device configured for receiving and aerating a flow of wash fluid to generate a flow of foamed wash fluid having particular foam characteristics. The flow of foamed wash fluid passes through a distribution manifold where it is selectively directed through a plurality of wash lines to desired portions of the gas turbine engine. The wash system further includes a controller configured for manipulating the foam characteristics of the flow of foamed wash fluid and using the distribution manifold to selectively direct the flow of foamed wash fluid to desired portions of the gas turbine engine for optimal cleaning and improved engine efficiency.