Florissant/Dunn Sanitary Relief (St. Anthony Ln to I-270) (#12178)

Florissant Dunn Sanitary Relief (12178)

As part of a long-term effort to reduce basement backups, MSD Project Clear is constructing approximately 6,170 feet of wastewater sewer in the City of Florissant. The Florissant/Dunn Santiary Relief project will increase the size of the wastewater sewer which will reduce instances of basement backups.

About the Project

Public Meeting - April 18, 2023

Project Map

What is the goal of this project?

MSD Project Clear is investing approximately $4.75 million to design and construct this project to ultimately alleviate instances of building backups and allow the wastewater system in this neighborhood to carry more wastewater flow. More than 6.000 feet of larger, newer wastewater sewer will be installed. This project is estimated to benefit 2,185 properties.

Project Facts

  • Construction is estimated to begin in Spring 2023.
  • Construction is estimated to last between 24 and 26 months.
  • MSD Project Clear will install approximately 6,170 feet of wastewater sewer.
  • The pipe size will range from 8 to 24-inches, allowing a larger amount of wastewater to flow through the system.

What can residents expect?

Type of Construction:

Like with any type of construction, residents can expect to see and hear heavy equipment during the sewer excavation process. The vast majority of this project will be constructed by a method known as “open-cut construction”. This means that crews will dig through the surface of the ground to excavate and install pipe.

A smaller portion of the project will be installed by using the pipe in tunnel method under Interstate 270 to avoid any traffic disruption on the highway. Boring holes will be dug on either side of the Interstate, allowing pipe to be installed underground without having to excavate the surface.

Traffic Impact: 

As a part of this project, MSD Project Clear does expect traffic impacts to roads in this area. Temporary road closures are expected but the construction crews will work diligently to keep these closures during work hours. One lane of traffic will be maintained at all times. The following roads are estimated to have traffic impacts due to this project: Elm Street, Duschene Drive, South New Florissant Road, and West St. Anthony Lane.

MSD Project Clear does expect times of temporarily reduced access for residential and commercial properties throughout the construction of this project. However, these timings will be temporary and the Contractor will work to minimize these instances and provide notice beforehand.


The Contractor will restore the construction site according to all District and local requirements. This could include sodding any disturbed areas, replacing disturbed pavement, reinstalling fences, etc.

What is the timeline?

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

  • Estimated construction start: Spring 2023
  • Estimated project duration: 2 years

Design Public Meeting - Septtember 2021


For the most part, yes. However, there may be temporary disruptions when sewer construction crosses driveway entrances.

There may be temporary disturbance of these features. MSD’s contractor will restore fences and mailboxes as necessary and replace disturbed vegetation with new sod.


Stay Informed

Andy Day
MSD Project Manager, Engineering Department

Please mention the Project Number: 12178