CSO Mary Avenue South of Manchester Road (12140)

CSO Mary Avenue South of Manchester Road (12140)

As part of a long-term effort to reduce basement backups and sewer overflows, MSD Project Clear is designing a project in the City of Brentwood to separate a combined sewer into two separate sewers, one for stormwater and one for wastewater. This project is estimated to begin construction in the summer of 2026.

About the Project

Public Meeting - September 14, 2023

Project Map

What is the goal of this project?

MSD Project Clear is investing approximately $30 million to separate the sewers in the City of Brentwood and increase the size of the wastewater and stormwater pipes. This will reduce the likelihood of basement backups in homes and businesses and will allow MSD to remove one constructed overflow point (known as a CSO) from its wastewater sewer system.

Project Facts

Construction is estimated to begin in the summer of 2026.

MSD Project Clear will construct approximately 9,850 feet of wastewater pipe and 3,750 feet of stormwater pipe.

The pipe size will increase to between 8 and 36 inches in diameter, allowing a larger amount of water to flow through the system.

What can residents expect?

Though construction for this project is not estimated to begin until the summer of 2026, it is important to be prepared for what to expect. While much of the construction will take place in existing easements, MSD may need to obtain new easements from some property owners. Prior to construction, residents whose property will need to be accessed to construct the project will be contacted to obtain the necessary easements or to be notified of work that will take place in existing easements.

What is the timeline?

This is the current tentative project schedule. This is subject to change based on a variety of factors including weather.

  • Complete project design: Late Summer 2023
  • Easement acquisition completion: Late Summer 2025
  • Estimated construction start: Late Summer 2026
  • Estimated project duration: 3.5 years


Q1: Will trees be removed as part of this project?

A1: Trees may need to be removed to construct parts of this project. Property owners with trees that will need to be removed that are not located in already existing easements will be compensated for the removal through the easement acquisition process. If there are good options to avoid removing trees, MSD will make every attempt to do that.

Q2: Will construction disrupt sewer service or other utility services?

A2: While MSD’s contractor is connecting a home’s lateral to the new wastewater sewer, they may ask residents to limit water use. In general, this process can take between two and five hours, depending on the complexity of the connection. The contractor will notify property owners in advance.

Q3: Will sewer or other utility services be disrupted during construction?

A3: MSD does not anticipate other utility services being disrupted during this project. We will work with Missouri One Call to locate utilities before beginning construction. Occasionally, the contractor may run into utilities that were not located by Missouri One Call which could result in temporary utility disruptions. If this happens, MSD will work with the utility to restore service as quickly as possible.

Q4: Will construction affect access to my property?

A4: During active construction, some property owners may experience driveway access restrictions for a short period of time. The contractor will notify property owners in advance of any temporary access restrictions to allow them time to move their vehicles. The contractor will also fill trenches with gravel or place steel plates over trenches during non-working hours so residents can use their driveways during those times.

FAQs section updated as questions are sent in to the Project Manager. To send your question in, please contact the Project Manager.

Stay Informed

Patricia Pride
MSD Project Manager

Erin Jearls
HDR Contractor