The link above is to a page on the Jefferson County website posted under the Public Works section. The paragraph below from that page strongly implies that the decision has already been made to construct the Hadlock sewer (see words in bold).
Jefferson County, WA is developing a sewer system for the Irondale & Port Hadlock Urban Growth Area (UGA) to provide wastewater treatment for local residents and businesses. The sewer system has been identified as a critical element for increased regional economic development. When construction of the sewer system is completed, the Irondale & Port Hadlock UGA will be able to support affordable housing, medical facilities, higher density multifamily residences, senior housing, as well as commercial and industrial development.
The list in that paragraph of the things they claim would be supported by construction of the Hadlock sewer – these are all things that would be required to meet the criteria for state and federal grants to help finance the project.
Port Townsend already has a sewer system and yet one-third of its business and residential land still sits empty. There is insufficient demand and no need to open up areas for high density development in Port Hadlock.
Port Townsend recently received a state grant to build a 43-unit low income apartment building – a much less expensive solution for affordable housing than building a $100 million sewer in Hadlock.