NSF/ANSI 58: Reverse Osmosis Drinking Water Treatment Systems
December 18, 2025
Reverse osmosis systems and components fall within the scope of NSF/ANSI 58. To learn about the requirements and certification process for this standard, check out this informational piece.
This standard includes requirements addressing various aspects of point-of-use (POU) reverse osmosis (RO) systems, including:
- Safety of materials in contact with drinking water (including content in accordance with NSF/ANSI/CAN 372)
- Structural integrity
- TDS (total dissolved solids) reduction performance
- Efficiency rating
- Recovery rating
- Contaminant reduction performance
- Information for the end user.
Claims available under NSF/ANSI 58
Standard NSF/ANSI 58 includes test procedures to verify various claims that can be made for your RO system, including:
Required
- TDS (total dissolved solids) reduction.
Optional
- Cyst reduction
- Hexavalent and trivalent chromium reduction
- Arsenic reduction
- Nitrate/nitrite reduction
- Cadmium reduction
- Lead reduction
- Barium reduction
- Turbidity reduction
- Fluoride reduction
- Copper reduction
- VOC reduction
- Asbestos reduction
- Perchlorate reduction
- Radium 226/228 reduction
- Selenium reduction
- Pentavalent arsenic reduction.
Learn more about our water filtration services
Test and certify water filtration and treatment systems, tailored for municipal, residential, or commercial use.
How NSF Can Help You
Get in touch to find out how we can help you and your business thrive.
What’s New with NSF
Spritzer Becomes First Malaysian Bottled Water Brand Certified by NSF for Beverage Quality
May 21, 2026The leading Malaysian bottled water and beverages brand has earned NSF certification from ANSI-Accredited Product Certification Body – Accreditation #0216.
NSF Annual Review and Impact Report 2025 Now Live
April 20, 2026NSF has published its Annual Review and Impact Report 2025, detailing the organization’s progress over the past year and outlining strategic priorities for 2026.
Visit NSF at Making Pharma 2026
April 10, 2026Connect with our experts to discover how we help leading pharmaceutical and biotechnology companies achieve regulatory compliance and operational excellence.