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What to Know About Copper Service Lines and Water Quality

Copper service lines remain a standard in drinking water systems due to their strength, formability, and long service life. For utilities, maintaining water quality in systems that include copper depends on a clear understanding of corrosion behavior, system chemistry, and regulatory requirements under the Lead and Copper Rule Improvements (LCRI).

What to Know About the EPA Copper Action Level and LCRI Requirements

How Does Copper Enter the Water System?

Copper in drinking water can originate from both the distribution system and building plumbing. This includes copper service lines, utility-owned piping, and interior plumbing, including pipes, fittings, and fixtures. When undesirable conditions, such as the presence of aggressive chemicals, make water corrosive, or when flow conditions promote corrosion, small amounts of copper can dissolve from these materials into the water.

The National Sanitation Foundation (NSF) explains that this process is driven by corrosion, which occurs when water chemistry, solids, or high velocity interacts with metal surfaces. Factors such as pH (acidity), temperature, and contact time influence how much copper is released when the water is aggressive. Water chemistry that remains in pipes for extended periods can become aggressive if the system is not properly maintained.

Stagnation is a key variable. When water sits in pipes, in vacant buildings, or during periods of low use, copper levels can rise before the water is used. This is why sampling protocols are designed to capture first-draw conditions that reflect potential exposure.

Over time, copper plumbing can develop a natural internal layer (patina) that reduces the amount of copper released into the water. Maintaining stable water chemistry, proper velocity, and proper installation support this process and help limit variability across both the distribution system and building plumbing.

For utilities and project teams, copper levels at the tap reflect conditions across the full system, from distribution infrastructure to building plumbing. Managing those conditions through consistent water quality control is central to limiting copper release.

What to Know About the EPA Copper Action Level and LCRI Requirements

The U.S. Environmental Protection Agency (EPA) first established the copper action level of 1.3 mg/L, based on the 90th percentile of tap sampling results, under the Lead and Copper Rule in 1991. Unlike lead requirements, which have continued to evolve through subsequent rule revisions, the copper action level has remained unchanged.

Although the final Lead and Copper Rule Improvements (LCRI) update changes several compliance requirements, the most significant changes focus on lead, not copper. The final rule requires replacement of lead and certain galvanized service lines, strengthens tap sampling procedures, and lowers the lead action level. By contrast, copper remains regulated at the 1.3 mg/L action level established in 1991.

It is important to understand that the toxicological profiles of lead and copper resulting from drinking water exposure are very different, despite both being regulated under the same Lead and Copper Rule.

The bottom line is this: Because lead is toxic even at extremely low levels, the lead action level set in the Lead and Copper Rule is only 0.015 parts per million (15 parts per billion). This is eighty-seven times lower than the 1.3 parts per million action level set for copper.

The final LCRI includes a dedicated section on tap sampling for lead and copper and retains corrosion control treatment as a core compliance element. It also keeps service line inventory and public communication requirements within the broader rule framework, which matters for systems evaluating materials, sampling locations, and customer notification responsibilities.

Health Impacts: Copper Versus Lead

While lead and copper plumbing materials have been delivering water to communities for thousands of years, researchers learned only in the 20th century that these two materials have very different toxicological profiles.

Thus, as mentioned earlier, although they are both regulated under the same regulatory framework of the Lead and Copper Rule, lead and copper differ greatly in the types of adverse health effects that may arise following drinking water exposure and in the concentrations at which these effects may occur.

Copper is an essential trace element:

  • Copper is necessary, like some other metals, in the daily human diet to maintain good health because of the vital life-support functions that it provides. Without adequate copper intake, humans get sick.
  • Copper is essential to the healthy development and regulation of red blood cells, iron, cholesterol, glucose, immune systems, and the destruction of damaging free-radicals.
  • A small amount of dietary copper should be consumed daily for good human health.
  • According to CDA’s service line health effects fact sheet, copper is an essential nutrient, but elevated levels in drinking water can lead to short-term gastrointestinal effects such as nausea and stomach irritation, but do not cause long-term health issues. These effects are typically associated with higher concentrations (4 to 5 times above the regulated level) and shorter exposure periods.
  • Chronic exposure to copper is particularly a concern for people with Wilson's disease, an autosomal recessive genetic disorder of copper metabolism affecting 1 in 30,000 individuals (Ala et al., 2007).

Lead is a neurotoxin that can cause long-term health effects:

  • Even at very low exposure levels, no amount of lead in children's blood is considered safe by any health authority.
  • The EPA has set a goal of “zero” parts per million of lead in drinking water because no safe level of exposure has been established.
  • Since 2014, federal law has prohibited the installation of pipes, fittings, fixtures, and solder used for drinking water that do not meet the "lead free” requirement of no more than 0.25% weighted average lead content on wetted surfaces.

How do you Manage Copper Levels in Drinking Water Systems?

Corrosion control is the primary method for managing copper levels in drinking water systems, starting with proper design and installation and continuing as an ongoing operational function.

Effective corrosion control depends on proper system design and maintaining water chemistry conditions that support the formation and stability of a protective patina inside copper pipes. This patina often consists of copper oxides and carbonate-based compounds. Disruptions to this layer can increase copper release.

Key operational parameters include:

● pH control: Slightly alkaline conditions reduce copper solubility and support the formation of a patina

● Alkalinity and dissolved inorganic carbon: Promote carbonate scale development

● Oxidant management: Disinfectants influence surface reactions and scale composition

● Corrosion inhibitors: Compounds such as orthophosphate are used in some systems to reduce metal release

Corrosion control programs require continuous monitoring and adjustment. Changes in source water, treatment processes, or distribution system conditions can alter corrosion dynamics. CDA recommends evaluating these changes and maintaining optimized treatment.

Frequently Asked Questions

What is EPA’s copper action level, and how is compliance determined under the LCRI?

The copper action level is 1.3 mg/L, assessed at the 90th percentile of tap sampling results. Under the Lead and Copper Rule Improvements (LCRI), copper is regulated using a treatment technique: systems must conduct tap sampling, maintain corrosion control, and respond if the 90th percentile exceeds 1.3 mg/L.

How does copper get into drinking water, and why can levels differ between homes or sampling sites

Copper can enter water through plumbing materials and fixtures, especially during stagnation. Corrosion processes, influenced by factors such as installation, design velocities, pH, alkalinity, and temperature, drive their release, leading to varying concentrations across different taps. New copper installations may release higher levels initially until stable internal patina forms.

What is corrosion control, and which conditions help limit copper release

Corrosion control involves managing water chemistry to form and maintain protective films, such as copper oxides, on the interior of pipes. Key practices include maintaining a slightly alkaline pH, sufficient alkalinity and dissolved inorganic carbon for carbonate scale formation, managing oxidants/disinfectants, and, sometimes, using inhibitors such as orthophosphate. Continuous monitoring and adjustment are essential, especially when source water or treatment conditions change, as disruptions can destabilize protective films and increase copper release.

Why is the lead action level so much lower than the copper action level

Lead and copper have very different toxicological profiles. Lead is a neurotoxin with no safe blood level in children, and the EPA's action level for lead in drinking water is 0.015 mg/L. Copper, an essential trace nutrient. The action level for copper is higher at 1.3 mg/L, about 87 times that of lead, reflecting their differences.

What did the final LCRI change for copper in drinking water systems?

Nothing. The LCRI updated lead regulations while maintaining the existing framework for copper, focusing on tap sampling and corrosion control, and following up on action-level exceedances. It includes sections on lead and copper tap sampling, service line inventory, and public communication requirements for selecting sampling locations and for customer notifications.

Marcus Elmer

Vice President of the Copper Development Association

Marcus Elmer, Vice President of the Copper Development Association, is a seasoned professional with over 15 years of experience in the plumbing and mechanical industries. He leverages his expertise to identify and influence market trends for copper tube and fittings products, driving strategic programs encompassing technical research, codes and standards, advocacy, and education. With a unique perspective gained from his time as a project manager with commercial plumbing, mechanical, and refrigeration contractors, Elmer has a deep understanding of the industry.