Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Wastewater Infrastructure topic
No spam. Unsubscribe anytime.
Environmental Services outlines progress on wastewater comprehensive plan; identifies capacity and condition needs
Summary
Environmental Services presented a multi-year wastewater comprehensive planning effort that documents aging infrastructure, capacity projections tied to population growth, regulatory drivers including nutrient and PFAS work, and near-term steps for analyses and funding evaluation.
Environmental Services staff on Wednesday briefed the Infrastructure Planning and Sustainability Committee on the wastewater comprehensive plan effort, describing current system condition, regulatory drivers and next steps for capacity, condition assessments and funding strategies.
Assistant Division Manager Dana De Leon and Principal Engineer Theresa Peterson described work to establish baseline boundary conditions for the city’s wastewater utility, a multiyear effort that staff said will inform capital project alternatives, risk quantification and a prioritization framework. Peterson said the utility manages about 700 miles of sewer pipe, roughly 44 pump stations and two treatment plants — the Central Treatment Plant (built 1952; major upgrades in 1979, 1988 and 2008) and the North End Treatment Plant (built in 1968; last major upgrade in 1998).
Staff reported condition and capacity findings from ongoing inspections and modeling. For the collection system, staff said it has inspected roughly 98% of pipe through an 8–10 year cleaning and video-inspection cycle; the current condition snapshot classifies about 33% of piping as good, 55% fair and 12% poor. For pump stations, staff said roughly 20% are in good condition, 62% fair and 18% poor; several stations are undergoing phased upgrades. Preliminary treatment-plant modeling and flow/load projections identified a future need for a larger solids-handling upgrade at the Central Treatment Plant; staff said a high‑level alternatives analysis is complete and more detailed design and phasing analysis will follow.
Regulatory drivers discussed included National Pollutant Discharge Elimination System (NPDES) permits, the Puget Sound Nutrient General Permit and monitoring and planning requirements for contaminants of emerging concern including PFAS. Staff described an on-site PFAS pilot at the Central Treatment Plant with an anticipated off-site pilot in February and said they will complete a nutrient-reduction evaluation later in 2025.
Peterson said population-growth projections from the Puget Sound Regional Council (PSRC) were used to model future flows and inform capacity planning; staff intends to update models and projections at least every five years. On funding, staff described two needs: (1) ongoing renewal and replacement for the existing system and (2) capacity to meet growth. The utility is developing financial models to evaluate long-term renewal and replacement funding needs and staff said they are evaluating system development charges (SDCs) for new and redevelopment to recover capacity-related costs. Staff noted Tacoma is among the few jurisdictions that currently do not charge such SDCs and that consultants are preparing comparative analyses.
Committee members asked technical and policy questions about coordination with permitting, how asset degradation influences wastewater treatment, and interactions among potential fees, impact fees and other developer obligations. Staff said they will continue condition assessments, refine phasing and cost estimates for identified projects and return with more detailed funding and prioritization proposals.
