What Public Water Utilities Should Know About Perchlorate Water Testing
Regulatory attention on emerging contaminants in drinking water continues to increase, with perchlorate remaining a focal point of ongoing federal and state discussions. Perchlorate is a chemical used in rocket fuel, fireworks, military munitions, and other industrial applications, and it can enter drinking water sources through manufacturing, disposal, or environmental persistence.
For public water utilities and system operators, understanding where perchlorate regulation stands — and where it may be headed — is essential for long-term planning, monitoring strategies, and compliance readiness.
Regulatory Background: How Perchlorate Reached This Point
Perchlorate was first determined to meet the criteria for regulation under the Safe Drinking Water Act (SDWA) by the U.S. Environmental Protection Agency in 2011. However, in July 2020, the EPA withdrew its determination to establish a federal drinking water standard for perchlorate.
At the time, the agency cited several factors, including cost-benefit considerations and the conclusion that a national rule might not provide meaningful additional public health risk reduction beyond existing state-level actions. The EPA also noted that some states had already adopted enforceable perchlorate standards.
That position changed in 2023. In May of that year, the U.S. Court of Appeals for the D.C. Circuit vacated and remanded the EPA’s 2020 withdrawal, directing the agency to continue the regulatory process under the SDWA. As a result, the EPA committed to moving forward with federal rulemaking for perchlorate.
Where We Are Now (As of Early 2026)
After administrative and review delays, the EPA signed a proposed National Primary Drinking Water Regulation (NPDWR) and Maximum Contaminant Level Goal (MCLG) for perchlorate on January 2, 2026. The proposal was published in the Federal Register on January 6, 2026.
The proposal includes:
- A proposed MCLG of 20 parts per billion (ppb)
- A request for public comments on enforceable limits of 20, 40, or 80 ppb
It is important to note that these values are proposed, not final. The EPA has indicated that the final rule is anticipated by May 21, 2027, though timelines remain subject to change based on the rulemaking and review process.
Federal and State Standards: Why the Gap Matters
While the federal process continues, several states have already established their own enforceable perchlorate standards. For example:
- Massachusetts has adopted a 2 ppb standard
- California has adopted a 6 ppb standard
In contrast, other states, including Texas and Arizona, do not have enforceable drinking water standards for perchlorate and instead rely on advisory or guidance levels. Louisiana currently has no perchlorate-specific drinking water standard.
As a result, utilities in states without enforceable limits would primarily rely on the federal NPDWR if it is finalized, making awareness of proposed thresholds and timelines especially important.
Advocacy organizations such as the Natural Resources Defense Council have argued that a proposed federal limit of 20 ppb may not be sufficiently protective for vulnerable populations, including fetuses and young infants. These perspectives are part of the broader public comment process that the EPA considers during rule development.
What This Means for Public Water Utilities
Although the final regulatory outcome for perchlorate remains uncertain, utilities do not need to wait for a finalized rule to begin preparing.
Key considerations include:
- Understanding whether perchlorate is present in source water or distribution systems
- Evaluating existing monitoring data in light of potential future standards
- Incorporating emerging-contaminant awareness into long-term planning and capital decisions
Perchlorate water testing can provide utilities with baseline data to support informed decision-making, risk communication, and regulatory readiness as federal and state requirements continue to evolve.
AmSpec Group’s Role in Perchlorate Water Testing
AmSpec Group supports perchlorate water testing as part of its broader environmental testing capabilities for public water systems.
Within this framework, A&B Labs, now operating as part of AmSpec Group’s Environmental Testing division, provides analytical testing services to support utilities monitoring emerging contaminants. By delivering defensible laboratory data aligned with current regulatory expectations, AmSpec helps utilities understand potential exposure and prepare for future compliance requirements.
Frequently Asked Questions: Perchlorate Water Testing
What is perchlorate, and why is it a concern in drinking water?
Perchlorate is a chemical associated with certain industrial and defense applications. In drinking water, it is primarily a concern because it can interfere with thyroid function, particularly in sensitive populations.
Is there currently a federal drinking water standard for perchlorate?
As of early 2026, there is no finalized federal drinking water standard for perchlorate. The EPA has proposed an NPDWR and is in the process of soliciting public comment before issuing a final rule.
Why should utilities consider perchlorate testing now?
Testing allows utilities to establish baseline data, understand potential exposure, and evaluate how future federal or state standards could affect operations and compliance planning.
Do state perchlorate standards override federal rules?
If finalized, a federal NPDWR would apply nationwide. States may maintain or adopt more stringent standards, but federal requirements establish a minimum compliance baseline.
Learn More About Water Testing Services
To learn more about water testing and how AmSpec Group supports public water utilities addressing emerging contaminants, visit our Environmental Testing page or contact our team to discuss your testing needs.