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Investigative Process for Lead Service Lines


Determining your service line material

Because property owners, not Denver Water, own water service lines, details about the material of an individual property’s service line have been inconsistent and scattered among a variety of sources. But as part of the Lead Reduction Program, Denver Water has developed a comprehensive inventory showing the location of known and suspected lead service lines in our service area.

Denver Water and its contractors are employing a variety of investigative methods to confirm the material of a service line as part of our effort to develop and maintain this publicly accessible inventory. The inventory continues to be refined as more information is gathered through the methods outlined below. Each of these methods is part of a multi-part approach. 

Records analysis

Most of the available information on service line material at the start of the program included property records and information on the date for when a service line was connected to Denver Water’s main in the street. In Denver Water’s experience, homes built before 1951 are more likely to have lead service lines, but in some rare cases lead service lines may be present in homes built after 1951. 

Adequate documentation from property owners, such as a contractor receipt, showing that a service line has previously been replaced in full (from the main to meter and meter to home) can also be used to confirm service line material.

Water testing

Having a lead service line doesn’t necessarily mean you have elevated levels of lead in your water. However, water testing is a simple method for customers to identify potential risks of lead exposure. We may send you a FREE water test kit if we suspect your property may have a service line containing lead. 

It is important that you collect your water samples by closely following the instructions provided with the kit, and return the samples, free of charge, within 48 hours of collection to obtain accurate results.

The water test kit for single-family homes will contain three sample collection bottles and step-by-step instructions. Photo credit: Denver Water.

Visual observation

In addition to water testing, Denver Water may request to inspect the water service line at the point of entry into the home. This will require an appointment where the resident can provide access to the entry point into the property. In some cases, this may be behind appliances or furniture that will need to be moved before the appointment. The access point may also be in a crawl space or behind a wall. 

In some situations, a copper service line may have been partially installed either from the street to the water meter or from the meter to the house. Along with potholing, described below, this visual observation can confirm the material present at specific points along the service line. 

Denver Water field crews or its contractors may inspect the pipe at the main water shut-off valve inside the property to help determine the type of material. Visual inspection will be arranged with the property owner in advance. Photo credit: Denver Water.


A pothole inspection will help determine the material composition of the water service line underground. Prior to the inspection, the contractor will request locates on utility lines, which will be marked with paint or flags before the inspection. The contractor will then excavate two holes, typically one in the street and one in the yard between the meter and building, so that the line can be inspected. This includes a visual inspection, photographs, magnetic and scratch tests if necessary, and documentation. Additional potholes may be needed to confirm service line material if initial potholing and other investigative methods do not show the presence of lead. The holes are restored following the inspection. 

The potholing process takes place outside of the home or building; however, we would prefer a homeowner or building representative to be on-site during the inspection so that we can also conduct the visual observation of the service line as it enters the home or building.

What the investigative methods tell us

Denver Water may use one or all of the investigative methods to confirm the presence of a water service line containing lead. Any one of these methods may confirm the presence of a service line containing lead, but it takes a combination of these methods to confirm the absence of lead. 

If it is confirmed that a property has a lead service line, the property will remain enrolled in the Lead Reduction Program. The program replaces customer-owned lead service lines with copper service lines at no direct charge to you. Beginning in 2020, it will take 15 years to replace all the lead service lines in our service area, and work will continue through 2035. There are many factors that determine when we will replace lines in your area. Denver Water is using this inventory and a sophisticated model, both of which are constantly being updated with new information, to guide decisions about where to look for lead service lines and the timing of replacing these lines. Each fall, Denver Water will use the model, along with coordination around other construction projects, to identify proposed work areas for the following year.

You will receive additional information before replacement. 

Until then, please be sure to use the water pitcher and filter provided to you. Remember, boiling water does not remove lead. 


If it is confirmed that your water service line is made of copper through a combination of these methods, your property will be removed from the Lead Reduction Program. You will receive a letter outlining these results.