LA County Sanitation District outlines emergency sewer repairs, larger rehabilitation and force‑main replacement in Hermosa Beach

The Los Angeles County Sanitation Districts told the Hermosa Beach Public Works Commission on Tuesday that crews completed an emergency overnight repair in December after a sewer crown collapse and are now lining a nearly 100‑year‑old trunk sewer that runs from Fourth to 10th streets.

The presentation described the emergency scope, the short-term construction impacts for residents and the schedule for the larger rehabilitation work that will follow. The district also described a separate force‑main replacement tied to the Herondo pumping plant that crosses city streets on Monterey Boulevard.

Why it matters: the trunk sewer that runs north–south through Hermosa Beach is a regional pipeline owned and operated by the Los Angeles County Sanitation Districts. The line serves multiple cities and, according to district staff, has sections more than a century old; a failure can cause soil erosion beneath pavement and trigger sinkholes or larger collapses. The district said the emergency work and the planned lining reduce collapse risk ahead of a broader project planned for 2026.

What the district said

Abbas Ismail, introduced himself as a project manager and resident engineer for the sanitation districts and described work the agency did after a December collapse near Fourth and Bayview. "The lining is a very quick and painless process," Ismail said, describing cured‑in‑place pipe (CIPP) as a one‑day operation for each short reach once bypass pumping is installed. He said crews completed the immediate repair, backfilled the void below the asphalt and then planned staged lining operations to minimize traffic and driveway impacts. The bypass piping will run aboveground along Monterey Boulevard during lining; the district plans phased work block by block and intends to maintain pedestrian access to sidewalks.

A second district presenter, identified in the meeting as Artin (staff member), said the larger Hermosa Beach rehabilitation will cover roughly 8,000 feet of sewer and is meant to update much of the city’s main trunk with CIPP liners. "Once we're through your sewer through all of Hermosa Beach will be practically brand new," he said, estimating the larger project will be constructed in sections so impacts are localized.

Leo Juarez, a civil engineer in the Sanitation Districts' Sewer Design Section, described a separate force‑main replacement tied to the Herondo pumping plant. Juarez said the pumping plant, built in 1970, operates with only one active force main because an original main was taken out of service in 1991. "The original force main has been out of service this whole time," Juarez said, and the districts plan to install a new HDPE force main along the existing alignment on Monterey Boulevard to restore redundancy. That project is open‑trench construction for roughly 1,300 linear feet; the district expects limited side‑street closures and daytime work during excavation.

Schedule and neighborhood impacts

District staff provided a near‑term timeline for the emergency lining: bypass installation and trenching across intersections were under way in late January, with lining scheduled to begin on February 3 and finish by February 7 for the initial reaches; the contractor planned to demobilize by Feb. 14. Ismail said lining each short reach typically takes a few hours with an overnight cure and that the most disruptive element for residents is the bypass pumping and aboveground discharge lines.

For the larger rehabilitation of the roughly 8,000‑foot reach, staff said they expect contract selection in August, physical construction to begin early the following year and the work to be staged in discrete sections so most residents are affected only for short periods. For the Herondo force‑main replacement the district indicated a tentative construction start in April with completion anticipated by January of the following year.

Service interruptions and contingency measures

Commissioners pressed the district about whether residents could use household plumbing during the work. The district said most homes in Hermosa Beach connect to local lines that then flow into the county trunk; only about 15 properties directly connected to the county trunk will be affected during portions of the larger rehabilitation and could face brief, day‑long service interruptions. For those properties the district said it will provide portable restrooms and hand‑washing stations.

Ismail said the bypass lines will divert local flows downstream so crews can work on a dry trunk segment; pumps will run 24 hours and are diesel‑driven but enclosed. He said the district uses two parallel pipes in bypass configurations to provide redundancy and reduce the risk of overflow during peak flows.

Other program context

The district overview included background on wastewater reuse, solid‑waste operations and the county's work to convert organic waste into energy and compost. The presenters noted the sanitation districts’ work on recycled water, groundwater recharge and compliance with California’s organics recycling mandate, SB 1383.

What the commission asked and directed

Commissioners asked for clarification about service impacts, bypass routing, timing, noise and coordination with other utilities and city paving. City staff said they are coordinating closely with the sanitation district and with California Water Service (Cal Water) on overlapping work on Bayview Drive. Commissioners recommended expediting related reaches where feasible to reduce the risk of future emergencies.

Ending note

District staff said construction notices and outreach materials will be posted at wlacsd.org/construction and that the districts offer presentations and facility tours for community groups.