Lead and Copper Rule: Action Levels, Testing, and Replacement

The Lead and Copper Rule is the federal drinking water regulation that requires public water systems to sample tap water for lead and copper, treat water so it doesn’t corrode plumbing, inventory and replace lead service lines, and notify the public when contamination crosses federal thresholds. The Environmental Protection Agency first issued the rule in 1991 and significantly strengthened it in October 2024 through the Lead and Copper Rule Improvements, known as the LCRI.¹ The LCRI lowers the lead action level from 0.015 mg/L to 0.010 mg/L starting November 1, 2027, and sets a hard ten-year deadline to replace every lead service line in the country.

Lead and copper rarely come from the source water itself. They leach out of corroding pipes, solder, and fixtures between the water main and your tap, which is why the rule focuses on controlling water chemistry and getting hazardous pipes out of the ground.

Who the Rule Covers

The rule applies to community water systems and non-transient, non-community water systems under 40 CFR Part 141, Subpart I.² Community systems serve year-round residents in neighborhoods and municipalities. Non-transient, non-community systems serve the same people regularly but not residentially, such as schools, hospitals, and office buildings that have their own water supply. A system is covered if it has at least fifteen service connections or regularly serves at least twenty-five people.

Homes on private wells are not covered by the Lead and Copper Rule. If your drinking water comes from a private well, contact your local health department for information about testing.³

Action Levels for Lead and Copper

The rule sets concentration thresholds called action levels. Cross one and the system has to take specific corrective steps. The copper action level is 1.3 mg/L. The lead action level is 0.015 mg/L through October 2027, dropping to 0.010 mg/L on November 1, 2027 under the LCRI.⁴

These are not Maximum Contaminant Level violations. They are regulatory triggers. A system evaluates them using the 90th percentile of all valid samples from a monitoring period: rank the results from lowest to highest, look at the value at the 90th percentile mark, and compare it to the action level.¹ Exceeding the level forces the system to optimize corrosion control, expand public education, and in some cases distribute filters. The 90th percentile design keeps a single unusual result from penalizing an otherwise compliant system while still flagging widespread contamination.

The LCRI also adds an individual-site response. Any single tap sample above 0.010 mg/L triggers a Distribution System and Site Assessment: a follow-up sample, a review of whether localized corrosion control adjustments are needed, and results delivered to the consumer at that address within three business days.⁴ Systems with two or more action level exceedances within five years must submit a filter plan to the state. Three or more, and they must give consumers lead-certified filters and replacement cartridges.

How Water Systems Test for Lead and Copper

Sampling is designed to catch worst-case conditions in the distribution network. Systems first identify Tier 1 sites: single-family homes served by lead service lines or with copper plumbing joined by lead solder installed between 1983 and 1988, when lead solder was still legal.⁵ A system has to exhaust Tier 1 sites before dropping to lower tiers.

The protocol calls for a first-draw sample: one liter of cold water taken from a kitchen or bathroom tap after the water has sat still in the pipes for at least six hours. Residents helping with collection cannot remove or clean the faucet aerator or flush the tap before the stagnation period starts.⁶ That overnight stagnation captures the peak concentration of metals that have leached from plumbing while the water sat.

Under the LCRI, sites served by lead service lines require a paired first-liter and fifth-liter sample. The first liter reflects water sitting in the building’s internal plumbing; the fifth liter reflects water sitting inside the lead service line itself. The higher of the two values counts toward the 90th percentile calculation.⁷ Standard monitoring runs on six-month cycles, with the number of required sites scaling to the population served. Systems with a clean track record can qualify for reduced monitoring, but any system that still has lead or galvanized-requiring-replacement service lines in its 2027 baseline inventory has to return to standard monitoring for at least two consecutive rounds.⁸

Corrosion Control Treatment

When a system exceeds an action level, the first response is optimizing corrosion control. The state designates the optimal treatment and sets target ranges for pH, alkalinity, and corrosion inhibitor concentration that the system must hold.² Systems evaluate several approaches, sometimes in combination:

Adjusting pH and alkalinity so the water is less corrosive to metal surfaces.
Adding orthophosphate-based inhibitors, which build a protective mineral coating inside the pipes.
Adding silicate-based inhibitors as an alternative coating approach where phosphate is impractical.

Compliance is reviewed every six months. A system falls out of compliance if water quality parameter excursions occur on more than nine cumulative days in any six-month period.² Monitoring happens both at entry points to the distribution system and at customer taps.⁹

Lead Service Line Inventory and Replacement

Every covered water system has to build and maintain an inventory of the service lines connecting its water mains to individual buildings. Initial inventories were due in October 2024. A more refined baseline is due by November 1, 2027, and that baseline locks in the replacement schedule for the following ten years.¹⁰

Each line falls into one of four categories:¹¹

Lead.
Galvanized requiring replacement, meaning a galvanized line downstream of a lead source.
Non-lead, verified as copper, plastic, or another safe material.
Lead status unknown, when records and inspection cannot confirm the material.

The public version of the inventory has to include a street address or unique locational identifier for each line. Systems serving more than 50,000 people must post their inventory online; smaller systems can make it available by other means such as at the utility’s office or by mail. Starting January 30, 2029, systems submit updated totals every year showing service line counts and how many replacements happened.

The biggest change in the LCRI is a blanket requirement to replace all lead service lines within ten years, whether or not a system exceeds the lead action level.¹² Replacement plans are due to the state by November 1, 2027. The first program year runs November 1, 2027 through December 31, 2028. Systems with an unusually high proportion of lead lines may qualify for a deferred deadline if their average annual replacement rate exceeds 39 replacements per 1,000 service connections under a ten-year schedule.

The rule mandates replacement of the utility-owned portion of the line. Who pays for the homeowner’s side is not settled at the federal level. The LCRI does not specify a payment structure, so the financial burden on private property owners varies by community. Replacing the private portion of a lead service line typically runs from a few thousand dollars up to around $20,000, depending on length, depth, and local labor rates. Many municipalities are using federal infrastructure funding to cover all or part of the homeowner cost, but there is no guarantee.

Testing at Schools and Childcare Facilities

The LCRI requires community water systems to sample for lead at the schools and licensed childcare facilities they serve. Facilities built on or after January 1, 2014 with complete plumbing replacement are generally exempt, unless they are served by a lead, galvanized-requiring-replacement, or unknown service line.¹³

For elementary schools and childcare facilities, the water system must sample at least 20 percent of covered facilities each year for five years starting November 1, 2027, so every facility gets tested during that initial cycle. After that, testing continues on request. Secondary schools are sampled on request only from the start. The protocol uses 250-mL first-draw samples collected after an 8- to 18-hour stagnation period. Schools get five samples from drinking fountains, kitchen faucets, classroom taps, and a nurse’s office faucet. Childcare facilities get two. Water systems must notify a facility 30 days before sampling and report results to the facility, local and state health departments, and the state within 30 days of receiving lab data.

Public Notice and Consumer Education

When a system’s 90th percentile exceeds the lead action level, it has to issue a Tier 1 public notification within 24 hours. That requirement applies at 0.015 mg/L now and shifts to 0.010 mg/L on November 1, 2027.⁴ Notices go out by mail, hand delivery, or electronic posting on the system’s website.

Beyond the 24-hour notice, a system that exceeds the lead action level must deliver printed public education materials to every person it serves within 60 days after the monitoring period ends. Federal rules dictate specific content:¹⁴

A mandatory opening statement warning that lead levels are elevated and that lead poses serious health risks, especially for pregnant women and young children.
A health effects section explaining that lead exposure can decrease IQ and attention span in children and increase risks of heart disease, high blood pressure, and kidney problems in adults.
An explanation of how lead enters drinking water, including lead service lines and other sources such as paint and soil.
Steps residents can take, including flushing pipes, using cold water, using certified filters, and getting children’s blood tested.
A description of what the system is doing to address the problem, along with a history of lead levels in tap water samples.

Even when results stay below the action level, systems provide annual consumer confidence reports that disclose detected lead and copper levels. Systems must also send annual notifications to consumers whose service line is lead, galvanized requiring replacement, or unknown.

Failure to meet notification deadlines, sampling requirements, or treatment obligations can result in administrative or civil penalties under the Safe Drinking Water Act, reaching tens of thousands of dollars per day per violation.¹⁵ The actual amount depends on severity and duration, and states with primary enforcement authority may add their own penalty structures.

What You Can Do at Home

Regulatory compliance is the water system’s job, but a few practical steps can meaningfully cut your own lead exposure:³

Flush the cold-water tap, take a shower, or run the dishwasher before drawing water for drinking or cooking. Flushing time depends on whether your home has a lead service line, so ask your utility for specific guidance.
Use cold water only for drinking, cooking, and mixing baby formula. Hot water dissolves lead more readily, and boiling does not remove lead. It concentrates it.
Install a filter certified to remove lead and replace cartridges on schedule. Never run hot water through a lead-rated filter.
Clean your faucet aerator regularly. Lead particles and sediment collect in the screen at the tip.
Find out what your service line is made of. Contact your utility, or if the utility serves more than 50,000 people, check the online service line inventory.
Ask your utility to test your water, especially if you live in a home built before 1988 or served by a lead service line.

1
Environmental Protection Agency. Lead and Copper Rule
2
eCFR. 40 CFR Part 141 Subpart I – Control of Lead and Copper
3
Environmental Protection Agency. Actions to Reduce Potential Lead Exposure
4
Environmental Protection Agency. Final Lead and Copper Rule Improvements Frequently Asked Questions for States and Public Water Systems
5
Environmental Protection Agency. Lead and Copper Rule Tier Schedule
6
eCFR. 40 CFR 141.86 – Monitoring Requirements for Lead and Copper in Tap Water
7
Federal Register. National Primary Drinking Water Regulations for Lead and Copper Improvements (LCRI)
8
Environmental Protection Agency (EPA). Final Lead and Copper Rule Improvements (LCRI) Fact Sheet – Small Water Systems
9
eCFR. 40 CFR 141.87 – Monitoring Requirements for Water Quality Parameters
10
Environmental Protection Agency. EPA Final Lead and Copper Rule Improvements Technical Fact Sheet – Service Line Inventory and Replacement Requirements
11
U.S. Environmental Protection Agency. Planning and Developing a Service Line Inventory
12
Environmental Protection Agency. Final Lead and Copper Rule Improvements Technical Fact Sheet – Deferred Deadlines for Service Line Replacement
13
Environmental Protection Agency (EPA). Lead and Copper Rule Improvements (LCRI) Fact Sheet – Lead in Schools and Child Care Facilities
14
Environmental Protection Agency. Instructions for Public Education Under the Lead and Copper Rule
15
Environmental Protection Agency. Safe Drinking Water Act and Federal Facilities