The sewer system in Monmouth has a colorful history, enough to justify a whole chapter in Scott McArthur’s book Monmouth Oregon: The Saga of a Small American Town.
In the early years, everyone had to dispose of their own waste, usually into a garden or down a privy. The Normal School ran a drain north through the property of Mr. Thomas Gentle and poured its waste directly into Ash Creek.
The city had the option to install sewer lines when Main St. was paved in 1916 but chose not to. The engineer in charge wishfully said "Putting down a pavement without a sewer would be poor policy under general conditions but in the case of Main Street it would be alright".
The Normal School was also feeling optimistic that year having installed a septic tank that was intended to “destroy all sewage…within twenty-four hours” leaving “almost pure water.”
In 1925, with sewage seeping into lawns, effluent trickling into streets and the school’s tank overflowing, voters came to the conclusion that a united solution was in order. A bond was passed, sewer lines were laid and all buildings, including the Normal School, were connected to the system which sent waste under Catron street out to a 45’ by 52’ municipal septic tank not far from this cache. Unfortunately, the tank was poorly operated and untreated water regularly flowed into Ash Creek.
By 1951 that system was taken out of service (eventually becoming part of Gentle Woods Park) and Monmouth started sending its waste to a shared facility in Independence where Ash Creek empties into the Willamette (now Riverview Park).
In 1964 Monmouth ended the alliance and plugged the sewer line running through Independence (except for that one time in the ‘70s when the plug accidentally fell out and Independence unknowingly processed much of Monmouth’s waste for free.)
Today the city’s largest sewer line still flows under Catron Street where the nearby pump station sends it to a modern treatment plant located on the banks of Ash Creek east of Gentle Woods–a fitting location for a system that has always been connected to the creek.