EPA published updated Quick Reference Guides for PFAS National Primary Drinking Water Regulation (NPDWR) implementation in February 2025. The guides cover Control of PFAS Overview, Initial Monitoring, Hazard Index, Significant Figures and Rounding Requirements, and Compliance Monitoring. Updates include the addition of EPA method 537.1, version 1.0 as an approved analytical method for the initial monitoring period. These guides assist Nevada water systems in understanding and complying with the April 2024 PFAS NPDWR requirements.