Washington State Expands Oversight of PFAS in Biosolids

As the environmental and public health risks of PFAS (per- and polyfluoroalkyl substances) continue to escalate, Washington State is taking a decisive step to address their presence in biosolids. Under the amended Senate Bill 5033, adopted April 10, 2025, the state will implement a phased program requiring biosolids facilities to test for PFAS compounds and report their findings to the Department of Ecology.

Strengthening Oversight Through Measured Action

The revised legislation—formally codified through the 5033-S AMH APP H2149.1 amendment—builds on existing biosolid regulations by explicitly mandating sampling, analysis, and reporting on PFAS levels in municipal sewage sludge. The updated statute acknowledges the dual role of biosolids as both a potential agricultural resource and a public health concern due to contaminants such as heavy metals and emerging pollutants like PFAS.

Under the new law:

• By July 1, 2026, the Washington Department of Ecology must publish guidance outlining PFAS sampling frequency and methodology.
• Facilities that generate biosolids will be required to conduct PFAS testing quarterly, beginning no later than January 1, 2027, using EPA Method 1633A.
• All sampling data must be submitted to the Department by September 30, 2028.

A Data-Driven Approach to Regulatory Development

Rather than rushing to impose immediate PFAS thresholds or bans, the amendment emphasizes a measured, data-first approach. The Department of Ecology is tasked with releasing a comprehensive PFAS in biosolids report by July 1, 2029. This report will include statewide data on PFAS levels in land-applied biosolids, along with policy recommendations for next steps.

To support the development of this report, Ecology must consult an advisory committee by September 30, 2028. This group will include representatives from:

• The farming and agricultural sector
• Toxicology experts
• Public and municipal utilities
• Local government officials
• Soil amendment producers
• Other stakeholders with environmental and public health expertise

Focused Scope and Regulatory Accountability

The legislation clarifies that the PFAS testing requirement applies only to biosolids—not to septic tank sludge, or “septage.” It also directs the Department of Ecology to work collaboratively with local health departments and the regulated community to evaluate permit fee structures, supporting greater cost transparency and program efficiency.

A newly designated biosolids permit account will hold all fee revenue, ensuring that funds are strictly used to support oversight, inspections, and technical assistance related to biosolids management.

Aligning with Federal Standards and Futureproofing Policy

This move by Washington follows growing national and international concern over PFAS contamination and echoes federal efforts under the Clean Water Act and recent EPA health advisories. By using EPA's testing protocols and establishing a timeline for evidence-based recommendations, the state is creating a framework that prioritizes both regulatory compliance and environmental resilience.

As biosolids continue to be utilized in agriculture, silviculture, and land reclamation, the new requirements aim to safeguard public health without undermining beneficial reuse.