Cypress Trunk Sewer Project

Cypress Trunk Sewer Project

The Cypress Trunk Sewer Project continues to make progress as crews move into the next phase of work near the intersection of Denni St. and Lincoln Ave.

Upcoming Work

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

Three bypass systems will be installed to safely reroute sewer flow before pipe replacement takes place. Each system will take approximately two weeks to install and require day and night work. Once installed, the bypass systems will operate continuously until construction is complete. Pipe replacement will then begin during nighttime hours.

• When: Starting as early as Monday, Sept. 21 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. northern driveway
    • Other left turns may be restricted during work hours; please follow all posted signs
  • Casa Grande Apartments Access: 
    • Residents traveling northbound on Denni St. should access the complex from the southern driveway of Casa Grande Cir. Other left turns into the complex will be restricted
  •  Increased noise and activity, including generator noise from the bypass pumps

Current Work

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

Crews are preparing for the last portion of pipe replacement in Forest Lawn Cemetery. This includes excavating and setting up a bypass system. Once preparation is complete, pipe replacement and manhole work will take place.

• 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