South Shore Sewer Study

Making Wise Investments in our Sewer System

The City is studying how rain and groundwater get into our sewer system – called inflow and infiltration, or I&I. As sewers age, they leak more, allowing rain and groundwater to enter the sewers and mix with the wastewater. There are also places where drains from roofs or parking lots allow rainwater directly into the sewers.

The problem with I&I is that when clean rain or groundwater get into the sewer system, it takes up capacity that could be used for dirty sewer water. We don’t want to pay to build bigger pipes when a much cheaper alternative is to keep clean water out of the sewer system.  

The City of Lake Oswego wants to find cost-effective ways to reduce I&I. We are using a portion of the South Shore basin within the McVey-South Shore and Palisades neighborhoods as a pilot area.

The first step in the pilot study is to test the public sewer system to find the sources of I&I – that testing has begun and will continue through spring 2019. If you are in the South Shore area, you may notice workers installing equipment to measure sewer flows, taking videos of the inside of the pipes (called CCTV) or using smoke to find places where water can enter the sewers.

Information from the study will help identify improvements that offer the best reduction in I&I for the lowest cost – pointing to wise investments in our sewer system.

Frequently Asked Questions

Where is the testing happening?

Testing is happening in a portion of the McVey-South Shore and Palisades neighborhoods.

What types of testing is the City doing?

Testing includes installing monitors that measure sewer flows, taking videos of the inside of the pipes (called CCTV), and using smoke to find places where water can enter the sewers.

Is the testing safe?

Public safety is our number one priority. All testing methods are completely safe to residents and pets and are routinely used in communities across America.

Will I notice the testing in my home?

Most of the testing will take place in the public right-of-way. During smoke testing, you may notice smoke coming up through the ground or coming out of manholes. In some cases, smoke may enter your home if there is a problem with your plumbing. The smoke is completely safe for people and pets – it is white to gray in color and is non-toxic, odorless, non-staining, and does not pose a fire risk.  If you experience smoke in your home from the testing, please call or email Pat McDougal at or 503-635-0273.

Are these tests really needed?

The City wants to find the most cost-effective projects to reduce I&I – those that offer the greatest reduction in I&I for the lowest cost. Those projects can’t be identified without knowing where I&I is coming from in the City’s system.

When is the testing happening?

Testing started in early 2019 and will continue into the summer of 2019. Testing is scheduled for completion by August 2019.

Need more information?

Please email Pat McDougal or call 503-635-0273.

Contact Information

Pat McDougal - Project Manager