Lead Service Lines in Colorado

Your water system's inventory is the record that answers that for your address: it is the utility's account of what it believes each line is made of, and in Colorado 141,284 lines, 7.7 percent of everything reported, are recorded as lead status unknown. No public dataset answers it for a single address, and EPA's own rule language for the unknown category is "Identify the material of all unknown service lines by the replacement deadline." The sequence is: find the systems serving your area with the ZIP tool on this page, read that system's inventory for your address, and if it says unknown, ask the utility what it plans to do about it. A laboratory test of your own tap is the only thing that measures your water.

As of the April to June 2026 federal extract, Colorado's 1,058 community water systems reported 18,792 lead service lines, 2,620 galvanized lines requiring replacement, 141,284 of unknown material and 1,662,259 non lead. 86 of those systems reported no service line types at all, which is not the same as reporting none: a blank is a blank. 817 systems report that every line they own has been identified.

It is EPA's fourth category and the one people find most surprising, because the pipe itself is not lead. In EPA's words: "A GRR service line is a galvanized service line that currently is or ever was downstream of an LSL or is currently downstream of a service line of unknown material." Galvanized iron and steel corrode into a rough interior that can trap lead particles washed down from a lead line upstream, and it keeps releasing them after that lead line is gone. That is why the rule treats it the same as lead for replacement. Colorado utilities reported 2,620 of them.

EPA's Lead and Copper Rule Revisions set the first deadline: "All systems must develop an initial lead service line (LSL) inventory by October 16, 2024, that includes all service lines, regardless of ownership, categorized as lead, non-lead, galvanized requiring replacement (GRR), and unknown." The Lead and Copper Rule Improvements then added a second, fuller one: "Develop an updated initial service line inventory, called the LCRI baseline inventory, that includes updated service line information and connectors. The baseline inventory is due by November 1, 2027." On replacement, EPA states: "EPA is requiring water systems to conduct full replacement of all lead and galvanized requiring replacement (GRR) service lines that are under the control of the water system in 10 years or less, with limited exceptions, regardless of the water system’s 90th percentile lead level." In Colorado, 43 community systems carry a listed LSL Inventory violation in the federal file, EPA's record that the inventory owed was not produced.

The rule made each utility publish its inventory, not each state, so the Colorado document you want almost always lives with your water system, and no verified statewide lookup is linked here. EPA requires each inventory to be public, and "The inventory must be made publicly accessible and available online for systems serving > 50,000 persons." Use the ZIP tool above to get the names of the systems serving your area, then search that system's own website for its service line inventory, or call it and ask. Colorado Department of Public Health and Environment runs the drinking water program in Colorado and can say where a given system's inventory was filed.

No, and two separate things are worth keeping apart. The number EPA lists per system is a 90th percentile from Lead and Copper Rule tap sampling, computed across a targeted pool of higher risk homes, not a measurement of any one house. In Colorado, 980 systems have a result from a monitoring period ending in the last five years, and 5 of those sit at or above EPA's 15 parts per billion action level. The action level is not a health threshold: it is the point at which the rule requires a system to act, and EPA writes that "EPA and the Centers for Disease Control and Prevention (CDC) agree that there is no known safe level of lead in a child’s blood." 40 Colorado systems have no listed result newer than five years, so for those the federal record is simply old.

Yes, and this is the most common misreading of an inventory. EPA: "Among homes without lead service lines, the most common problem is with brass or chrome-plated brass faucets and plumbing with lead solder." The inventory covers the service line, the pipe between the water main and the building. It does not cover the plumbing inside your walls, the solder in its joints, or the fixtures on the end of it, and lead was legal in all three long after it stopped being used for service lines. That matters in Colorado in proportion to how much of it was built before 1986, and it applies to every one of the 1,662,259 lines Colorado utilities recorded as non lead just as much as to the 141,284 they have not identified. EPA also notes how lead gets in at all: "Lead can enter drinking water when plumbing materials that contain lead corrode, especially where the water has high acidity or low mineral content that corrodes pipes and fixtures. The most common sources of lead in drinking water are lead pipes, faucets, and fixtures."

From two federal records, both current to the April to June 2026 extract. The service line counts come from EPA's SDWIS service line inventory report, one row per water system, carrying EPA's four categories: for Colorado that is 1,058 community water systems and 1,824,955 reported lines. The tap results and the violation counts come from EPA's quarterly Safe Drinking Water Act download, which is where the 43 listed Colorado inventory violations and the 980 recent lead results on this page come from. Both are US Government works in the public domain. They cover reported service lines and compliance records; a specific address, anything a Colorado utility did not report, and private wells, which no lead rule covers, are outside both. EPA's own caution on the compliance data applies throughout: "Compliance statistics are based on violations reported by states to the EPA Safe Drinking Water Information System (SDWIS). EPA is aware of inaccuracies and underreporting of some data in this system. We are working with the states to improve the quality of the data."

In the older cities, almost always. 21 Colorado community systems reported at least one lead service line, and those systems together report serving 2.4 million people. EPA's framing of why it matters: "Where lead service lines (LSLs) are present, they represent the greatest lead exposure source in drinking water." The ZIP tool above lists the systems serving your counties and what each one reported, which is a far better guide than any statewide figure.