Cypress Trunk Sewer Project

Cypress Trunk Sewer Project

Crews are working both day and night on the Cypress Trunk Sewer Project, with the next major phase of work taking place near the intersection of Denni St. and Lincoln Ave. in the City of Cypress.

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Upcoming Work

Location: Denni St., from Lincoln Ave. to Rainier Dr.

Bypass systems will be installed to safely reroute sewer flow before pipe replacement takes place. Each system will take up to two weeks to install, then operate continuously until construction is complete. Once the bypass systems are installed, pipe replacement will begin during night hours.

• When: Starting as early as Monday, Sept. 14 and lasting until mid-November*
• Work Hours:
  • Night Work: Bypass Installation & Pipe Replacement
    • Sunday night – Friday morning, 8:00 p.m. – 6:00 a.m.*
  • Day Work: Bypass Installation  
    
    • Monday – Friday, 8:00 a.m. – 5:30 p.m.*
• Work Impacts:
  • Temporary and permanent traffic control with reduced lanes 
    • Permanent traffic control will be located around the bypass systems to protect crews and equipment, and may extend as far south as Surrey Dr.
  •  No left turns onto Denni St. from Rainier Dr. or Casa Grande Cir.
    • Other left turns may be restricted during work hours; please follow all posted signs
  •  Increased noise and activity, including generator noise from the bypass pumps

Current Work

Location: Denni St. and Crescent Ave. in the City of Cypress

The bypass systems and traffic control on Crescent Ave. and Denni St. have been removed, and steel plates are in place over the areas where excavation took place. Crews will be returning to remove the steel plates and complete minor street restoration ahead of the rainy season.

• When: Week of Sept. 7*
• Work Hours: Tuesday – Friday, 8:00 a.m. – 5:00 p.m.*
• Work Impacts:
  • No parking along the work area on Denni St.
    • Please move vehicles by the time shown on posted signs to avoid towing
  • Residential and emergency access to the neighborhood will remain
  • Turns may be limited during work hours
  • Temporary traffic control while work is performed with reduced lanes
  • Increased activity, dust, and noise levels

Location: Guardian Dr. within Forest Lawn Cemetery in the City of Cypress

Crews are currently preparing for pipe replacement, including excavating, installing bracing, and fusing pipe in Forest Lawn Cemetery. Once preparation is complete, pipe replacement will take place to replace the existing sewer pipe with a larger one.

• When: Ongoing – December 2026*
• Work Hours: Sunday – Friday, 8:00 p.m. – 6:00 a.m.*
• Work Impacts: Increased activity, dust, and noise levels

 *All dates and times are subject to change due to operational factors or inclement weather.

Project Description:

The regional sewer line in the cities of Cypress, Los Alamitos, and La Palma is approximately 50 years old and in need of upgrades. The Cypress Trunk Sewer Project will focus on enhancing about 7 miles of sewer, replacing portions of the pipe with larger diameter pipe to increase the capacity, or rehabilitating other segments of pipe to extend the life of the sewer system. Approximately 100 manholes will also be replaced and/or rehabilitated. These repairs will extend the life of the sewer pipes by another 50 years.

Schedule:
Construction began in Summer 2025 and is anticipated to last approximately 3 years.

Local Sewer Provider: 

• City of Cypress – Maintenance Division – (714) 229-6760
• City of La Palma – Public Works Division – (714) 690-3310
• City of Los Alamitos – Rossmoor / Los Alamitos Area Sewer District – (562) 431-2223