Contaminant · PFAS

9Cl-PF3ONS in drinking water

CAS 756426-58-1 · EPA record reviewed 2026-09-02

A chlorinated polyfluoroether sulfonate (component of F-53B) used in metal plating.

In focus10,307Systems tested nationwide

Public records. Clearer context.

Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages

systems where it was found

of 10,307 tested

0.01%

of tested systems found it

3.4 ppt

highest single result in EPA's survey

What the rules say

9Cl-PF3ONS has no federal limit or EPA health reference value.

Read the EPA source for 9Cl-PF3ONS.

Across the country

EPA tested 10,307 water systems for 9Cl-PF3ONS and found it in 1. Half of the systems that found it measured less than 3.4 ppt, and one in ten measured more than 3.4 ppt.

EPA's final UCMR 5 occurrence file contains 66,343 9Cl-PF3ONS results from 10,307 systems. 1 results were at or above the minimum reporting level, across 1 systems. Among detections, the median was 3.4 ppt and the 90th percentile was 3.4 ppt.

Systems with the highest recorded 9Cl-PF3ONS results

System	State	Population served	Recorded value	Records / periods
Ponca City Mun Water OK1021202	Oklahoma	27,155	3.4 ppt	1

Filters and testing

NSF/ANSI 58 (reverse osmosis)

A standard number by itself is not a contaminant claim. Check the product's current certification listing and performance data sheet for 9Cl-PF3ONS or the specific contaminant you want to reduce. A utility-level record is not a test of your own faucet.

From the national picture to your tap

Find your county. Then read the guide.

Your areaCheck your countyPick your state and county to see the water systems that serve it and what EPA recorded for 9Cl-PF3ONS.FiltersChoosing a PFAS filterHow to check a filter’s certified PFAS reduction before you buy.SurveyReading PFAS survey resultsWhat a detection, a reporting level and a yearly average mean in EPA’s survey.

Other PFAS in EPA’s survey

All contaminants