EPA Proposes New Lead Trigger Level to Reduce Exposure

The EPA’s new proposal to reduce childhood exposure to lead in drinking water seeks to strike a balance between the need for more protection and the stubborn complexity of the risk. Under the proposal, public water systems (PWSs) would be subject to six new general requirements (which include many more specific requirements), including taking an inventory of the lead service lines (LSLs) in their jurisdictions and more aggressively replacing these lines. Other provisions would improve water sampling, provide the public with better information about the risks of lead in their drinking water, and identify the levels of lead in drinking water in schools and daycare facilities.

One thing the proposal does not include is a maximum contaminant level (MCL) for lead in drinking water. Under the Safe Drinking Water Act (SDWA), the MCL is the highest level of a contaminant the EPA allows in drinking water; PWSs must achieve that level or risk enforcement. While the Agency has established MCLs for most drinking water contaminants, the SDWA indicates that the MCL must be economically and technologically feasible. LSLs are partially owned by the PWSs and partially owned by the homeowner. Given this dichotomy, the EPA has determined that an MCL for lead is not feasible because lead contamination in drinking water often results from corrosion of plumbing materials belonging to PWS customers over which the Agency and primacy states (states with EPA approval to implement the federal drinking water regulations) have no legal authority.

When the EPA cannot impose an MCL, the Agency establishes enforceable treatment techniques. In the proposal, the Agency is seeking to expand requirements that PWSs take certain actions (e.g., conduct a corrosion control study, treat for corrosion, reoptimize existing treatment, and replace LSLs) when certain levels of lead are detected in the system’s drinking water. The EPA recognizes the difficulties small PWSs and non-transient non-community water systems (NTNCWSs) face in improving the quality of water they provide; accordingly, the proposal would allow these systems several compliance flexibilities not available to larger systems.

The EPA notes that the proposal adopts a regulatory framework recommended in part by the Association of State Drinking Water Administrators (ASDWA). The proposal also incorporates many recommendations the Agency received from the National Drinking Water Advisory Council (NDWAC), a federal body established under the SDWA to advise the EPA about the national drinking water program.

A Danger to Children

Lead is a highly toxic pollutant that can damage neurological, cardiovascular, immunological, developmental, and other major body systems. No safe level of lead exposure has been identified for any age group. But the EPA is particularly concerned about the risks to children. Children absorb two to four times more lead than adults through the gastrointestinal tract. In December 2018, the Trump administration issued its Federal Action Plan to Reduce Childhood Lead Exposures and Associated Health Impacts. The intent of the plan is to reduce childhood exposure to lead from all sources (water, dust, soil, air, and food). One specific goal for the EPA is to revise its Lead and Copper Rule (LCR) “based on input EPA recently received from state, tribal and local partners, as well as the best available peer reviewed science, to ensure the rule reflects the best ways to improve public health protection and reduce levels of lead in drinking water.”

There are an estimated 6.3 million to 9.3 million homes served by about 50,000 miles of LSLs in thousands of communities nationwide. The EPA notes that data indicate the “possibility” of a disproportionately high and adverse human health risk from lead in drinking water among minority and low-income populations.

Long-Term Issues

Under the SDWA’s authority, the EPA issued the first LCR in 1991 to control lead and copper in drinking water at the consumer’s tap. The rule established National Primary Drinking Water Regulations (NPDWR) consisting of treatment technique requirements that include corrosion control treatment (CCT), source water treatment, LSL replacement, and public education (PE). The rule also established an action level (AL) of 15 parts per billion (ppb) for lead and 1,300 ppb for copper. The AL is a concentration of lead or copper in the water that determines, in some cases, whether a water system must install CCT, monitor source water, replace LSLs, and undertake a PE program.

In 2000, the Agency issued minor reporting revisions to the LCR. “Short-term” regulatory revisions followed in 2007 to ensure drinking water consumers receive meaningful, timely, and useful information to help them limit their exposure to lead in drinking water. At that time, the Agency also identified “long-term” issues that the current proposal addresses. The proposal does not include revisions to the copper requirements of the existing LCR.

Since 1991, the number of the nation’s large drinking water systems that have exceeded the LCR action level of 15 ppb has decreased by over 90 percent, and over 95 percent of the all water systems have not reported an AL exceedance in the past 3 years. But, as noted, small PWSs have yet to achieve that success rate and are constrained by limited funding and infrastructure that is past its useful life expectancy.

Suite of Actions

The EPA states that the proposal contains a suite of actions that “approach the problem of lead contamination in drinking water from different perspectives, but that taken together can further reduce lead exposure in drinking water.” This approach focuses on six areas:

• Identifying areas most impacted. To help identify areas most in need of remediation, the EPA is proposing that all PWSs complete and maintain an LSL inventory and collect tap samples from homes with LSLs if present in the distribution system. To reduce elevated levels of lead in certain locations, the EPA proposes to require water systems to “find-and-fix” the causes of these elevated levels. Key points:
  • All systems must develop an LSL inventory or demonstrate the absence of LSLs within the first 3 years of final rule publication.
  • The LSL inventory must be updated annually.
  • All PWSs with known or possible LSLs must develop an LSL replacement plan.

• Strengthening treatment requirements. The proposal would revise requirements for CCT based on tap-sampling results. A new trigger level of 10 ppb would be established. At this level, systems that currently treat for corrosion would be required to reoptimize their existing treatment. Also, at the AL, PWSs that do not currently treat for corrosion would be required to conduct a corrosion control study. Key points:
  • The intent of the corrosion control study is to evaluate the effectiveness of specific CCTs, including alkalinity and pH adjustment and the addition of an orthophosphate- or silicate-based corrosion inhibitor at a concentration sufficient to maintain an effective residual concentration in all test tap samples.
  • If the PWS already has CCT in place and the trigger level is hit, the PWS must reoptimize its CCTs.

• • Replacing LSLs. The EPA is proposing to require that PWSs replace the water system-owned portion of an LSL when a customer chooses to replace his or her customer-owned portion of the line. Also, PWSs would need to initiate full LSL replacement programs where tap sampling shows that lead levels in tap water exceed the AL. The proposal requires systems that are above the trigger level but at or below the AL to set an annual goal for conducting replacements. Systems that are above the AL would need to annually replace a minimum of 3 percent of LSLs or potential LSLs listed in the inventory at the time the AL exceedance occurs. The proposal also prevents systems from avoiding LSL replacement by testing out with an LSL sample, which is permitted under the current LCR. (Test-outs allow an individual LSL to remain in place but be counted as “replaced” if the lead concentration in all service line samples from that line is less than or equal to 15 ppb). Key points:
    • Systems above 10 ppb would be required to work with their state to set an annual goal for replacing LSLs.
    • Partial LSL replacements will no longer be allowed except in certain situations (e.g., emergency repair).

The EPA notes that research has found that partial LSL replacement may increase short-term lead exposure.

• • If a single customer served by an LSL does not accept the PWS’s offer to replace the customer-owned portion (the water system is not required to bear the cost of replacement), the PWS may proceed with a partial LSL replacement at that location to complete the main replacement project.
  • A PWS may discontinue its goal-based LSL replacement program after two consecutive annual monitoring periods at or below the lead trigger level, which equates to 2 years in which the lead 90th percentile is consistently at or below the trigger level.
  • Community water systems (CWSs) serving 10,000 or fewer people and all NTNCWSs exceeding the AL may select from three compliance options—CCT, LSL replacement, or provision and maintenance of point-of-use devices.

• Increasing sampling reliability. The proposal would prohibit tap-sampling instructions that call for prestagnation flushing and the cleaning or removing of faucet aerators. The proposal would add a requirement that tap samples be collected in bottles with a wide mouth. The EPA also wants to change the criteria for selecting homes with LSLs when collecting tap samples. For example, the Agency is proposing that sample site selection focuses on sites with LSLs rather than copper pipe with lead solder. Key points:
  • Resident volunteers would collect the water sample. The volunteers would be provided with instructions on how the water system will pick up samples for laboratory analysis, which must be done within 2 weeks after the tap sample is drawn.
  • The PWS would be required to calculate a 90th percentile separately for lead and copper at the end of each monitoring period. This 90th percentile value would be reported to the state and is used to determine whether the system must comply with other requirements of the rule, such as CCT, PE, and LSL replacement.
  • PWSs with higher levels of lead must sample more frequently.

• Improving risk communication. PWSs would be required to notify customers of an AL exceedance within 24 hours. PWSs would also be required to conduct regular outreach to homeowners with LSLs. In addition, the PWS would be required to the make LSL inventory publicly available; the inventory must include location identifiers. Key points:
  • Consumers would be informed annually that they are served by LSLs or service lines of unknown material.
  • PWSs subject to LSL replacement goals must conduct targeted outreach that encourages consumers with LSLs to participate in the LSL replacement program.
  • PWSs must conduct additional outreach if they fail to meet their LSL replacement goals.

• Checking schools. CWSs would be required to sample drinking water outlets at each school and childcare facility served by the system. The CWS would be required to provide the sampling results to the school or childcare facility and to conduct PE to inform the facilities about actions they can take to reduce lead in drinking water. Key point:
  • CWSs must test for lead in drinking water and undertake PE at 20 percent of K–12 schools and licensed childcare facilities every year.

The EPA anticipates issuing the final LCR amendments by July 2020.