How to Streamline Your Lead Service Line Inventory

By Susan Fenhaus, PE, and Kurtis DeShaw, PE – If you’re reading this article, you may have circled October 16, 2024, on your calendar. This is the Environmental Protection Agency’s (EPA) deadline to submit your water system’s Lead Service Line (LSL) inventory. While not due for a while, this project can be long and involves lots of planning and possibly some detective work on your part. We have combed through some helpful pieces of information to help streamline this process for you.

While following EPA’s guidelines, each state has provided tools and tips to help their community and non-transient non-community water systems complete and submit inventories of their service lines. This article will focus on the states of Montana, Wyoming, Oregon, and Washington and examine the EPA’s references.

Where to Look for LSL Information

The Montana Department of Environmental Quality (DEQ) created a Quick Guide to help Montana communities identify lead service lines. DEQ has also provided a template for their inventories. The Montana DEQ template and Quick Guide are useful regardless of where you live.

Here are some best practices for getting the information you need to complete your community’s inventory. Check the following:

  • Tap Cards or tickets from initial service installation.
  • Plans for water main installation, rehabilitation, and replacement.
  • Historic water utility records.
  • Tax records that show when buildings were constructed.
  • Plumbing permits.
  • Visual confirmation of pipe material by plumbers or utility crews during maintenance or installation activities.
  • Consult with other neighboring water systems to share experiences.

How to Identify Lead Service Lines

Depending on how complete your water system’s data and records are, you may have to consult several resources and conduct investigations to complete your inventory. Here are some guidelines from Montana DEQ that may help you gather the information you need:

  • Determine if any service lines were installed 30 years ago or more. In 1986, Congress prohibited using pipes, solder, or flux that were not lead-free. When filling out your inventory, remember that the year a house was built may differ from the year the service was installed to the curb stop. In this case, the service to the curb stop could have been installed before the prohibition of lead.
  • Determine if any short pieces of pipe—goosenecks or pigtails—were used to connect water mains to customer service lines.
  • Lead pipe was typically installed in smaller service line diameters. Identify service lines that are two inches or less in diameter. Three-inch lead service lines were rarely installed and can be identified as non-lead unless it is otherwise known to be lead.
  • Use technology like Eddy current testing to identify lead service lines.
  • Collaborate with your neighboring water systems to share experiences, resources, and equipment.

Physically Inspect the Piping

During your inventory investigations, you may encounter several types of piping. Here are four types of service lines and their characteristics.

Lead is a dull gray color and very soft. If scraped with a key or coin, it will turn a bright silver color. Even a strong magnet will not stick to lead.
Galvanized steel will remain a dull gray when scratched. A magnet will stick to galvanized. Galvanized pipe may have a lead gooseneck connection at the main.
Copper may be dull brown but will be bright like a penny if scraped. A magnet will not stick to copper.
Plastic lines will be blue or black. It will not change color when scratched and a magnet will not stick to plastic.

Using the LSL Inventory Template

Each state has its own method of reporting its water system service lines. EPA has an Excel template; many states are asking their communities to use it, while others have provided their own. Regardless of your state’s requirements, reviewing your regulatory agency’s website for guidance and best practices is worth your time before beginning your inventory. There may be helpful tips, lessons learned or other information to help you with your inventory.

The following links provide tips and instructions for preparing and developing your LSL inventory:



Montana DEQ requires that the inventory be completed in their downloadable template which can be found here.




Help is Just a Call Away

We have several employee-owners who have experience with the LSL inventory process. If you need assistance or have a few questions, don’t hesitate to contact us. We look forward to hearing from you!