What is Chlorine dioxide in drinking water?

Chlorine dioxide averages 12.0 violations per affected system (1,629 total / 136 systems) in the EPA SDWIS extract.

How many water systems have Chlorine dioxide violations?

136 systems sit in the mid footprint band (mid footprint (≤ 8,691 systems)).

Are Chlorine dioxide violations dangerous?

27.5% are health-based. The rest are monitoring/reporting, still compliance failures, but not the same as an MCL exceedance.

Where does Chlorine dioxide sit in the national contaminant ledger?

#98 of 157 indexable contaminants by violation volume - middle-third volume (≤ 49,133 violations), dense load (> 5.8 violations per affected system).

Where does this contaminant data come from?

EPA Safe Drinking Water Information System (SDWIS) quarterly extracts. Counts are cumulative compliance records, not a live risk score for a single tap.

Contaminants →

EPA SDWIS Dense per-system load

Chlorine dioxide in Drinking Water

Compiled by PlainWater · May 15, 2026

12.0 violations per affected system (1,629 across 136) - dense load (> 5.8 violations per affected system).

Browse all SDWIS contaminants →

EPA contaminant code: 1008

Total Violations

1,629

Systems Affected

136

Health-Based %

27.5%

Violations / System

12.0

Chlorine dioxide standing, mid-volume SDWIS third

Chlorine dioxide lands in the middle third by violation volume (1,629), large enough for peer comparisons but not one of the handful of analytes that dominate the fleet-wide SDWIS ledger. Load is concentrated: 12.0 violations per affected system (dense load (> 5.8 violations per affected system)), which usually means repeat findings on the same PWSIDs rather than one-off detections spread thin. Health-based share is 27.5% - a material slice of the record is exposure-relevant, with the rest monitoring or reporting. Among 157 indexable contaminants, this page is #98 by violation volume. Utilities listed below are ranked by cumulative violation count for this analyte; pair that with population served to gauge household exposure scale.

Nationwide similar contaminants

Nearest by violation volume

Turbidity (1,581) Bromate (1,422) Cryptosporidium (2,446) Chloramine (2,449)

Nearest by systems affected

Tritium (136 systems) 38-STRONTIUM-90 (138 systems) Coliform (Pre-TCR) (174 systems) Lead (78 systems)

Chlorine dioxide: mixed health vs monitoring split

27.5% health-based · 72.5% monitoring/reporting across 1,629 records.

Health-based (27.5%) Monitoring/Reporting (72.5%)

Most Affected Water Systems

System	State	Violations	Population
Perry Water & Light Dept	OK	221	5,230
City of Yuma	AZ	88	103,264
City of Yuma	AZ	67	103,264
Frederick Living	PA	56	640
Marworth Rehab Center	PA	52	178
Excela Westmoreland Hospital	PA	39	1,500
Chatham Co-North	NC	38	23,088
Franklin Water Supply	LA	35	8,325
Climax Molybdenum Co Henderson Mill	CO	34	165
Colorado City MD	CO	33	2,755
M & M WSC	TX	32	3,208
Jbsa - Sam Houston	TX	32	37,563
Magnolia Waterworks	AR	31	11,657
Pueblo West MD	CO	30	30,000
Oak Grove Water System	LA	30	2,955
Parish Utilities of Ascension	LA	27	9,732
Breckenridge PWS	MO	23	333
Todd Creek Village MD	CO	18	7,202
Montezuma WC	CO	18	13,797
Breckenridge PWS	MO	18	333
Lacygne, City Of	KS	16	1,119
Stroud Utilities Authority	OK	16	2,811
Rifle City Of	CO	15	9,489
Pagosa Area WSD	CO	14	11,069
Atoka Co. RWS & Swmd #4	OK	14	3,000
Creek Co RWD # 7	OK	14	2,100
Geisinger Medical Center	PA	14	6,442
Apache Junction Water District	AZ	12	15,610
Lacygne, City Of	KS	12	1,119
Antlers PWA	OK	12	2,547

Context: understanding water quality data · is my water safe?

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the EPA Safe Drinking Water Information System (SDWIS). Consult a qualified professional before making decisions based on this data.

Read our methodology - how this data is sourced, computed, and verified.

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.