Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Wastewater topic
No spam. Unsubscribe anytime.
Council reviews wastewater master plan update that pins 58% of flows on inflow and infiltration
Summary
City staff and consultants presented a master plan update that estimates 58% of flows are inflow/infiltration and recommends immediate and multi‑year projects, including a $531,000 jack‑and‑bore under State Street (E‑1) and several 10‑year/buildout gravity‑line installs.
South Salt Lake City Council received a presentation of the Wastewater Collection System Master Plan Update on Jan. 14, 2026. City staff and consultant Hansen, Allen & Luce laid out current conditions, modeling results and a capital plan to address capacity and inflow and infiltration (I&I).
The master plan reports that sanitary flow—what residents and businesses discharge directly into the sewer—is about 1.13 million gallons per day (MGD), while inflow and infiltration together averaged roughly 2.04 MGD (inflow) plus about 1.06 MGD (infiltration) in 2019, meaning about 58% of the water conveyed to the treatment plant is stormwater or groundwater, not sewage. The report recommends a mix of near‑term and longer‑term projects, expanded inspection and metering, and incentives for lateral replacement to reduce unnecessary flow.
Why it matters: higher non‑sewage volumes increase treatment costs, consume pipe and lift‑station capacity and can push the city toward larger, costlier projects. The plan projects system ERUs rising from 5,702 in 2024 to about 14,190 at buildout; modeled peak daily flows to the regional plant rise from about 4.58 MGD (2024) to roughly 5.98 MGD (buildout).
The report identifies maintenance hotspots and recommended immediate repairs. The primary existing project (E‑1) addresses a capacity deficiency at 2120 South across State Street: the report recommends a 30" jack‑and‑bore under State Street and replacing ~80 feet of 12" gravity line with a 15" line to correct a modeled depth/diameter ratio above the recommended threshold. The plan estimates E‑1 at $531,000 (including 20% for engineering/admin and contingencies, 2024 dollars). Future projects listed include two 10‑year gravity‑line installs (800 ft and 1,100 ft of 10" line, est. $336,418 and $462,575) and buildout 15" gravity work (est. $72,000 and $546,000).
The master plan also recommends operational changes: continue biennial system cleaning, video inspections every four years, install long‑term flow monitoring at key locations, and establish a rehabilitation budget (the 2021 I&I study suggested $500,000/year as a starting point; the update notes that about $3 million/year would rehabilitate the system in 25 years). The report frames these measures as means to reduce infiltration and inflow and thereby defer or downsize capital projects.
The resolution to adopt the updated master plan was listed on the council agenda; the transcript records presentation and discussion but does not show a recorded vote in the materials provided.
