GAO Finds eReporting of NPDES Data Incomplete and Inaccurate

An aerial view of an oil spill

September 14, 2021

As public accessibility of NPDES data increases, data quality is of growing importance for dischargers

A recent report by the U.S. Government Accountability Office (GAO) reviewed strategic changes implemented by the U.S. Environmental Protection Agency (EPA) since 2015 — including the introduction of an electronic reporting (eReporting) system — to advance compliance with the National Pollutant Discharge Elimination System (NPDES) program. The report, titled "EPA Needs to Better Assess and Disclose Quality of Compliance and Enforcement Data," found that data for only two of the 17 states where NPDES program performance was recently assessed met expectations for accuracy and completeness.

The current NPDES data reporting system requires states to post compliance and enforcement action information to the EPA's Enforcement and Compliance History Online website. Specifically, discharge monitoring reports (DMRs) provided by facilities to permitting authorities are transferred into the Integrated Compliance Information System (ICIS-NPDES). The original aim of the eReporting system was to improve tracking of NPDES compliance; however, as highlighted in the GAO report, its usefulness is limited due to incomplete and inaccurate state-reported data.

EPA has set a National Compliance Initiative with the goal of reducing the number of instances of noncompliance with NPDES permits by 50% by September 30, 2022. The current strategy of EPA's Office of Enforcement and Compliance Assurance (OECA) includes identifying and targeting 1,600 facilities with the most serious NPDES permit violations for enforcement actions. The GAO concluded, however, that the EPA's National Compliance Initiative does not provide a measure that quantifies water quality improvements, the true indicator of a successful enforcement strategy, and that additional outcome-based measurements are necessary.

Since the initiation of eReporting, the NPDES compliance and enforcement data provided by facilities have been increasingly readily available to the public. As users access compliance and enforcement action data through EPA's Enforcement and Compliance History Online website, the data limitations and potential inaccuracies resulting from instantaneous reporting may not be fully understood. Due the public nature and transparency that comes with eReporting of compliance data, it is of growing importance for NPDES dischargers to manage and report data accurately and appropriately and to achieve the highest level of data quality for NPDES-related testing and reporting.

How Exponent Can Help

Exponent's consultants have expertise in helping clients navigate federal and state regulatory requirements related to NPDES compliance. Our team has relevant experience reviewing and evaluating data characterizing water quality, sediment, toxicity, and ecological health. Exponent has additional expertise in negotiating permitting requirements, performing toxicity reduction evaluations, and evaluating treatment options and discharge scenarios, including the assessment of the appropriate dilution and mixing zone scenarios. Our extensive knowledge of the NPDES program allows us to develop solutions for regulatory compliance issues that our clients face at the state or federal level.