General Sewer Plan Update

City of Lynden Washington


The City of Lynden operates a wastewater collection utility, serving approximately 19,500 customers throughout its 2,879-acre Urban Growth Area. The City’s wastewater collection facilities include 57 miles of gravity sewers, over 4 miles of sewer force mains, and 14 pump stations that convey wastewater to the City’s Wastewater Treatment Plant (WWTP).  The WWTP is a conventional secondary treatment plant utilizing activated sludge and extended aeration.  The WWTP process also includes aerobic solids digestion, solids composting, effluent filtration, and effluent ultra-violet (UV) disinfection.  Treated wastewater is discharged to the Nooksack River.  Biosolids from the wastewater treatment process are either used to produce compost onsite for residents and agricultural uses or shipped for land application in Eastern Washington. BHC completed the City’s General Sewer Plan Update in October 2016.


  • Refining the long-range population and employment projections for the City’s service area
  • Updating the City’s system wide hydraulic model
  • Performing condition assessments of the City’s pump stations and WWTP
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