Lead Protection for Longmont Water

The City has nearly 31,000 service lines within our water system. To search for any evidence of potential lead service lines, an exhaustive review of historic documentation was conducted including: 

• water permits,  

• maintenance records,  

• project construction drawings,  

• legacy and retired staff interviews,  

• standards for approved construction materials.

No evidence was found showing that lead pipes were used to build water mains, service lines, or connectors (often called “goosenecks” or “pigtails”) after 1959. State officials determined all service lines for homes constructed after 1959 would be considered non-lead, given the findings of this records review. One exception was found where lead service lines may have been installed for some businesses on Main Street between 2nd Avenue and 6th Avenue in the early 1900s; however, all water service lines in this corridor were replaced during water line rehabilitation projects between 1987 and 1999.  

This investigation found that approximately 26,000 service lines are non-lead. The remaining ~4,000 water mains and service lines were deemed “unknown” and moved to Step 2 of the process. 

The Colorado Department of Public Health and Environment outlined a “minimum service line material verification (MSLMV)” process that provided guidance on how to statistically demonstrate if and where lead service lines are present in the water system. More information can be found on this selection process in Section 2.2.2 of the State of Colorado Safe Drinking Water Program Implementation Policy DW018. This statistical approach enables public water systems to draw conclusions about a large number of service lines from a smaller, randomly selected group of service lines. This process establishes a 95% confidence level that the system does not contain lead.

Following this approach, the City physically verified the pipe material for 351 randomly-selected and statistically representative water service lines. Each service line was physically verified in two locations: 

• Once on the system-owned side (shown in the Water Service Line Ownership and Responsibility image in blue) and  

• Once on the customer-owned side (shown in the same image in orange).
  

The City was able to physically verify each of these service lines through the following techniques: 

1. Customer participation with inspections of service lines where they enter the home
2. Visual verifications through the Waterline Replacement Program
3. Visual inspections conducted by the City of Longmont Operations and Maintenance Team
4. City-contracted services to expose and inspect the service lines.

The City of Longmont water service line investigation completed in 2024 resulted in a Non-Lead classification for all water service lines in the City.

While some historical records could be used as definitive evidence of non-lead service line materials (like engineering standards or recent maintenance records), many record types required more evidence to be deemed reliable.  Physically verifying a statistically representative number of service lines gave the City a unique opportunity to cross-reference the historical records used in Step 1 with findings in the field from Step 2.  

The City found consistency between the field investigations and information found in documents that may be perceived as unreliable or non-definitive (for example, notations on construction drawings, water permits, institutional knowledge and recollection, etc.). 

If a water system has been classified as “Non-Lead“, per the guidelines and processes set forth by the Colorado Department of Public Health and Environment, the final step is to submit these findings to State officials. 

What about the remaining service lines that have not been field-investigated? The City is committed to continually updating our service line inventory. We do this by actively gathering information about service line materials from the following year-round tasks: 

• Pipe inspections through regular maintenance activities like meter pit inspections or meter replacements.
• Information from building permits where contractors are required to verify in-home piping materials
• Information gathered from annual waterline replacement projects.

If any lead service lines are found through these activities, additional investigations will take place in coordination with the Colorado Department of Public Health and Environment.