Water Line Replacement
Water Line Replacement Program Overview
Updated: Jan. 30, 2026
With more than 450 miles of water line delivering more than 5 billion gallons of high quality water to customers each year, it is critical that Longmont takes care of its water lines to provide a reliable and efficient service. The City’s annual Water Line Replacement Program contracts with private sector contractors for replacement of deteriorating lines.
The City of Longmont’s Water Line Replacement Project will be completed in multiple locations. You can see the schedule and scope of the project below. This schedule is an approximation and is subject to change based on weather and other factors:
Work Zone 1:
- Installation of a water main on Kiteley Lane between Mountain View Avenue and Lanyon Drive.
- Expected duration of work is early November to mid-December 2025.
- All work is complete in this zone.
Work Zone 2:
- Replace the water main on Pratt Street between 11th Avenue and the north end of Pratt Street.
- Expected duration of work is mid-November to late-December 2025.
- All waterline replacement work is complete in this zone. Final landscape restoration will be completed in the spring of 2026.
Work Zone 3:
- Replace the water main in the Juniper-Sumner Alley between 12th Avenue and Mountain View Avenue.
- Expected duration of work is late November to January 2026, depending on weather.
Work Zone 4:
- Replace the water main in Riviera Place east of Hover Street.
- Expected duration of work is early February to mid-March 2026, depending on weather.
Work Zone 5:
- Replace the water main in Longs Peak Avenue between Hover Street and the parking lot for the Sunset campus (Sunset Swimming Pool and Sunset Golf Course).
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- This will also include replacing water mains in Loomis Court, Longview Court, and the cul-de-sac of Crestridge Lane.
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- Expected duration of work is mid-February to late April 2026, depending on weather.
Impacts to the Community
- Traffic within the construction zones will be impacted during this work. Road closures to through traffic will be employed throughout the project to complete the work in a safe and efficient manner.
- Driveways within the work area may be closed for up to two hours. City or contractor personnel will notify customers before entrances are blocked by the water line installation.
- “No Parking” signs will prohibit on-street parking within the work zones as indicated by the signage.
- Customers may be affected by water outages.
- Main line connections can take up to 8 hours. Customers will be notified by door hangers placed 48 hours in advance of a planned outage.
- Individual service connections can take up to 1 hour. Customers will be notified by City or contractor personnel knocking on your door immediately before the outage.
- Work hours are typically weekdays 7 a.m. to 7 p.m.
- After water service is restored, it is a best practice to flush your water service line. You can do this by running cold water from your tap(s) until the water clears.
Your Dollars at Work
The Water Line Replacement Program is paid for through the Water Utility operating fund, which is funded through utility bills.
Selected Water Lines
This annual program prioritizes lines for replacement based on frequency of breaks and ability to complete multiple replacements in a consolidated area. The Water Line Replacement Program is a long-term, strategic effort. Breaks and basic care activities are performed through the City’s utility maintenance operation.
If your home or business is located in one of the replacement locations, you will receive a letter at least one week before the project notifying you of the work to be performed, timeline for completion and anticipated impacts to you.
Construction Process
City and contractor staff perform the following standard planned sequence for replacement of any water line.
- Locate utilities and cut pavement along new water line alignment
- Excavate and install new water line
- Tie in new water line to existing water line (location varies and is site dependent)
- Conduct water quality and pressure testing; usually takes a minimum of 7 days
- Connect individual water services
- Connect the new water line to the existing water line (location varies and is site dependent)
- Complete permanent asphalt paving and site clean-up
Contact
Please contact Water with any questions or concerns related to the Water Line Replacement Program.
Your water line is being replaced as part of citywide water line replacement maintenance program. The maintenance program identifies pipes that are older or prone to failure and replaces them to ensure a safe and efficient treated water distribution system.
Water service is only turned off for connections and is restored on the same day. Customers will have water service for the majority of the construction.
Water services will be turned off for water line tie-ins or service taps. Each customer affected by the shutdown will receive a door hanger 48 hours in advance.
- Water line tie-in:
- Due to the involved nature of a water line tie-in these operations typically take a full working day up to 8 hours.
- Service tap:
- 1 hour
The contractor should only be digging in front your house for 1 or 2 days. Contractor or City personnel will knock before your driveway is blocked to give you time to move your vehicles.
Trash, recycling and composting will be picked up at 7 a.m. on your regularly scheduled collection day.
Older cast iron pipes can be prone to internal and external corrosion. Internally, corrosion can cause rust buildup that restricts flow (called tuberculation), reduces pressure, and can lead to discolored water. Externally, soil conditions and moisture increase the risk of leaks and main breaks.
The City replaces aging cast iron waterlines with either ductile iron pipe (DIP) or polyvinyl chloride (PVC), depending on site conditions, use case, and project needs. Both materials provide long-term durability and protect water quality. DIP offers exceptional strength and resistance to external loads, while PVC is corrosion resistant, lightweight, and maintains smooth interior surfaces that preserve flow capacity. Together, these materials ensure a reliable and resilient water distribution system.
PVC water pipes are expected to last 75–100 years, depending on soil conditions,
operating conditions and installation quality.
In general, pipe failures can result from a combination of age, material degradation, and environmental stress. Common causes include:
- Aging infrastructure: Over time, materials naturally fatigue, especially those installed before modern standards were adopted.
- Corrosion: Metal pipes, such as cast iron or steel, can corrode internally or externally, weakening the pipe wall.
- Soil movement: Expansive soils, freeze–thaw cycles, or nearby construction can shift, or stress buried pipes.
- Pressure fluctuations: Sudden changes in system pressure can strain joints or fittings.
- Temperature extremes: Freezing conditions can cause water expansion inside pipes, leading to cracks or breaks. All the City’s water mains are buried deep enough to avoid failure due to freeze/thaw cycles. More shallow pipes, like service lines that come to your home, can sometimes be susceptible to this type of failure.
The City uses spatial analysis of break history and conducts condition assessments to identify and replace at-risk pipes, supporting reliable service and water quality. However, due to the system’s large size and the fact that all pipes are buried and difficult to inspect, some failures are unavoidable. Breaks, leaks, pipe age and other risk factors help us prioritize which mains to replace.
