The city is implementing a rehabilitation program to line clay sewers with a structural liner to create a new solid sewer pipe inside of the old pipe, without the need for excavation.

The City of Boulder's sanitary sewer system consists of underground pipelines used to collect and transport untreated wastewater to the city's wastewater treatment facility. A large portion of the city’s sanitary sewer system was constructed in the 1940s through 1960s when it was common to construct sewers using clay pipes. These sewer pipes are now beginning to reach the end of their useful life.

Report Sewer Backup or Maintenance


In the event of a sewer backup on your property, the city will respond and determine the cause of the backup and assist if possible. Sewer customers should be aware that the sanitary sewer service line is the responsibility of the property owner up to and including the connection to the city-owned sewer main. If the problem is determined to be in the sewer service line, it is recommend that you call a plumber to investigate and resolve the problem.


After hours staff respond to true emergency events, such as sewer backups, overflows and missing manhole covers.

Please report all emergency issues by phone (do NOT make an online service request) to ensure a prioritized response by city staff.

  • Emergency / After-hours Emergency

Utility Locates

Do NOT use Inquire Boulder to request utility locates prior to digging.

Know if Your Sewer is Being Rehabilitated

Written notice

The City of Boulder will mail you a letter at least two weeks before work is scheduled to begin. The city's contractor, Eco-Matrix, will then contact you three times to notify you of the work status:

  • 24 hours in advance of the start of the work by direct contact at your door (if you are not at home, Eco-Matrix will leave the attached sample door hanger on your front door)
  • Immediately before work begins (STOP using indoor water at this point)
  • After your sewer service has been reinstated (okay to use water after this)

If you have received a notice

Do not use indoor water while work is being conducted (exception: you may drink tap water during this time). The city's contractor, Eco-Matrix, will notify you 24 hours in advance of when work is scheduled to begin and will also notify you when work is completed and sewer service has been reinstated.

You may use water for outdoor use while the sewer maintenance is being conducted.

Traffic and parking

Traffic and on-street parking may be temporarily disrupted in the work area. If parking restrictions are needed, the city will post “no parking” signs 72 hours in advance of the work.

Frequently Asked Questions

I will be at home during the installation process. What activities should I avoid?

Do not dispose of any water via your indoor plumbing during construction. This includes most indoor plumbing fixtures such as toilets, sinks, bathtubs, showers, dishwashers, washing machines, floor drains, etc.

I forgot about not using water and accidentally flushed the toilet, washed my hands, etc. Now what?

Do not use any more water. Although your sewer service is blocked during the liner installation, there is typically sufficient storage in the service to accommodate accidental toilet flushing or hand-washing without causing a backup. If you used a lot of water, such as by taking a shower or running the dishwasher, check the floor drains or bathroom on your home’s lowest level for signs of a backup.

I own or manage a multi-unit building where the work will be performed. How do I ensure my tenants do not use water during the project?

If you have concerns regarding tenants using water during the installation process, please contact the Utilities Division at 303-441-3200. Arrangements can be made to shut off the water supply to the building during the installation process.

What does “sewer rehabilitation” mean?

The sewer rehabilitation process involves placing a liner into the sewer, inflating it to fit the shape of the existing sewer and then hardening it into a new solid pipe inside of the existing one. The process costs about a quarter of the traditional approach of excavating and replacing the old pipes with new ones, and it takes about half a day, instead of multiple days, to complete.

Will this work fix any issues with my sewer service?

Homeowners are responsible for their sewer services from the home all the way to and including the connection to the city main in the street. The city’s work only rehabilitates the city’s main sewers and will not impact or address any issues with your home’s sewer service. Local plumbing companies can use the same lining technology the city uses, which can represent a significantly cheaper alternative to replacing sewer service.

Why was the sewer in my neighborhood chosen for rehabilitation?

The city continuously inspects its sewer system for structural defects using a robotic camera. Approximately 70% of Boulder’s sanitary sewers were constructed in the post-World War II period using clay pipes. Over time, factors such as shifting soils or heavy traffic loads can cause these clay pipes to develop cracks and defects. The last inspection showed that the sewer serving your building had sufficient structural defects to warrant installation of a liner.

How is this work being paid for?

The Utility Division’s Sanitary Sewer Rehabilitation Program is funded by wastewater use rates paid by Boulder residents and businesses. In 2014, City Council approved a 30 percent wastewater rate increase to expedite rehabilitating the city’s aging sewer infrastructure. This additional funding will allow the city to rehabilitate or replace its clay sewers over a 20-year period versus the 100-year period allowed by previous funding levels.