North Platte River in Colorado
Colorado PFAS Policy 20-1: Reporting Requirements in Water Discharge Permits

Colorado’s Water Quality Control Commission (WQCC) recently published a policy document (Policy 20-1) that provides standard values (translation levels) for per- and polyfluoroalkyl substances (PFAS) in state waters. The WQCC is a rulemaking board within Colorado Department of Public Health and Environment (CDPHE) that develops policies and regulations related to surface water and groundwater.

The translation levels are based on the WQCC’s interpretation of narrative water quality standards, which are written into Colorado Regulations No. 31 and 41. The quantitative water quality standards recommended by WQCC in Policy 20-1 are named translation levels as they are effectively a translation from one language (the narrative) to another (quantitative values).

In addition to the translation levels, Policy 20-1 provides guidance for implementing the policy. This includes laboratory analysis, sampling considerations, implementation in the Discharge Permit System, and other topics related to PFAS monitoring.

What are the translation levels for PFAS?

The policy provides translation levels, in nanograms per liter (ng/L), for the following PFAS compounds.

Perfluorooctanoic acid (PFOA)*


Perfluorooctane sulfonate (PFOS)*


Perfluorononanoic acid (PFNA)


Perfluorohexane sulfonate (PFHxS)


Perfluorobutane sulfonate (PFBS)


* a short list of parent compounds (“precursors”) for PFOA and PFOS are also included in Policy 20-1

As with most things related to PFAS, there’s more to consider. First, the translation levels for PFOA and PFOS include parent compound “precursors.” Precursors are PFAS compounds that may partially degrade, forming PFOA or PFOS as end products. Inclusion of precursors in the standards is a unique feature of the Colorado policy. Second, the 70 ng/L translation level for PFOA, PFOS, PFNA, and PFOA/PFOS precursor compounds applies to each individually or the combined concentration.

What about the other PFAS compounds without translation levels?

According to CDPHE, the focus will be on those compounds with translation levels. Other PFAS compounds may be considered on a case-by-case basis if present at very high concentrations.

How will this policy be implemented?

CDPHE will be responsible for implementing Policy 20-1, and has published a 1-page Q&A document on implementation of the policy. CDPHE may require effluent monitoring for permitted “facilities with a likelihood of PFAS discharge to state waters” (CDPHE 2020) through duty to provide information letters or permit conditions. Effluent limits are not imposed via CDPHE’s implementation of Policy 20-1 but maybe implemented based on effluent monitoring results. According to CDPHE, effluent limits will not apply to surface water discharges related to construction dewatering, short-term remediation, and well development. Domestic wastewater treatment plants will have 5-9 years to apply source mitigation measures to address elevated PFAS concentrations.

What happens if a discharge exceeds the translation levels?

Ultimately, the answer to this question depends on whether a discharger has PFAS effluent limits in their permit. As noted, CDPHE’s implementation does not immediately implement effluent limits on potential PFAS-emitting dischargers. For facilities with permitted PFAS effluent limits, an exceedance of the permitted effluent limits for PFAS is treated no differently than an exceedance for any other constituent.

For facilities without permitted PFAS effluent limits, the exceedance of translation levels does not constitute a permit violation. When an exceedance of translation levels occurs at a facility without PFAS effluent limits in their permit, follow-on measures may be implemented such as source investigation or implementation of effluent limits.

What laboratory and analytical method should be used?

Policy 20-1 provides minimum laboratory qualifications, but does not provide a list of qualifying laboratories. Laboratory requirements include:

(a) The ability to meet quantification limits (QLs) for the list of 25 PFAS compounds (QLs for each of the 25 analytes are specified in Policy 20-1)

(b) The ability to analyze samples for PFAS in compliance with U.S. Department of Defense (DoD) Quality System Manual 5.1 (or later), Table B-15 (QSM Table B-15)

Regarding the analytical method, the United States Environmental Protection Agency (USEPA) has not promulgated a final method for PFAS in non-drinking-water matrices, but is expected to within the next year. Until the USEPA finalizes a PFAS laboratory method, laboratory compliance with QSM Table B-15 is required. Once finalized, a USEPA-promulgated analytical method for wastewater may supplant QSM Table B-15 requirements.

What next?

The timing of implementing Policy 20-1 will vary depending on the age of the permit and the type of discharge permit. The CDPHE Water Quality Division will revise the monitoring requirements to adhere to the new PFAS policy as existing National Pollutant Discharge Elimination System (NPDES) permits expire and permit renewals are required, and whenever existing permits are modified. Policy 20-1 is written with flexibility and may be updated as the toxicological dataset grows for PFAS compounds.

Are other states adopting similar policies?

Translation levels are unique to Colorado, although terminology differs significantly between states. As of October 2020, 24 states have adopted PFAS drinking water standards. The Interstate Technology and Regulatory Council (ITRC) provides a standard table summarizing state-specific standards, which is updated on a monthly basis. Most states do not have effluent limits, but have standards for drinking water, groundwater, and/or surface water.

What about the USEPA?

On November 22, 2020, the USEPA released a memo that describes recommendations for an interim Federal NPDES permitting strategy for PFAS. The memo was developed by an internal workgroup, in which all USEPA regions were represented. The memo presented three primary recommendations:

  1. The inclusion of PFAS in NPDES permit monitoring requirements, using a phased-in approach to account for ongoing USEPA analytical method development.
  2. Stormwater monitoring and pollutant control for municipal and industrial stormwater permits, addressing PFAS using traditional controls such as control measures, monitoring, stormwater pollution prevention plans (SWPPPs)
  3. Information sharing, using established platforms, such as a PFAS-permitting compendium on the USEPA’s NPDES Municipal Sources Resources website, and information sharing on the USEPA’s NPDES Permit Writers’ Clearinghouse.


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