Water Quality Report · Updated October 07, 2026
SIOUX CITY WATER SUPPLY
SIOUX CITY WATER SUPPLY delivers tap water graded F (49/100) by TapWaterSafety.org. The utility serves approximately 85,791 residents in SIOUX CITY, Iowa using groundwater under direct influence. The most significant water quality concerns are: PFAS contamination; Perfluorohexane sulfonate (PFHXS) significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Total PFOS and PFOA significantly above health guideline. For questions, the utility can be reached at 712-279-6150.
Is SIOUX CITY tap water safe to drink?
SIOUX CITY WATER SUPPLY delivers tap water that earns a grade of F (49/100) from TapWaterSafety.org — a poor rating, with significant contamination concerns and/or recent violations.
The utility serves 85,791 residents in SIOUX CITY, drawing from groundwater under direct influence.
Public testing data identifies 18 contaminants in this water above EWG's health-based guidelines, including: Perfluorohexane sulfonate (PFHXS), Haloacetic acids (HAA9), Total PFOS and PFOA, Total trihalomethanes (TTHMs), Bromodichloromethane, Haloacetic acids (HAA5), Trichloroacetic acid, Dibromochloromethane, Chloroform, Dibromoacetic acid, Dichloroacetic acid, Perfluorooctanoic acid (PFOA), Radium, combined (-226 and -228), Perfluorooctane sulfonate (PFOS), Perfluoropentane sulfonic acid (PFPeS), Nitrate, Chromium (hexavalent), Bromoform. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
EPA compliance record
Official U.S. EPA records for SIOUX CITY WATER SUPPLY (system ID IA9778054) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Stage 2 Disinfectants and Disinfection Byproducts Rule | Missed testing or reporting | 05/01/2024 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Quick actions for SIOUX CITY residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for SIOUX CITY WATER SUPPLY.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Perfluorohexane sulfonate (PFHXS) significantly above health guideline
Moderate concernPerfluorohexane sulfonate (PFHXS) detected at 20.8 ppt, 20750x above the EWG health guideline of 0.001 ppt.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 46.9 ppb, 781x above the EWG health guideline of 0.06 ppb.
Total PFOS and PFOA significantly above health guideline
Moderate concernTotal PFOS and PFOA detected at 4.37 ppt, 624x above the EWG health guideline of 0.007 ppt.
Contact SIOUX CITY WATER SUPPLY
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for SIOUX CITY
Filters matched to the specific contaminants in this water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 49/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Perfluorohexane sulfonate (PFHXS) PFAS |
20.8 ppt | 0.001 | 10.0 | — | — | — | — | EPA violation |
| Haloacetic acids (HAA9) Disinfection byproduct |
46.9 ppb | 0.06 | — | — | — | — | — | 781× over |
| Total PFOS and PFOA PFAS |
4.37 ppt | 0.007 | — | 100 | 100 | 0.007 | — | 624× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
57.6 ppb | 0.15 | 80.0 | 100 | — | — | — | 384× over |
| Bromodichloromethane Disinfection byproduct |
17.3 ppb | 0.06 | — | — | — | — | — | 289× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
22.0 ppb | 0.1 | 60.0 | 60 | — | — | — | 220× over |
| Trichloroacetic acid Disinfection byproduct |
9.85 ppb | 0.1 | — | — | — | — | — | 99× over |
| Dibromochloromethane Disinfection byproduct |
8.88 ppb | 0.1 | — | — | — | — | — | 89× over |
| Chloroform Disinfection byproduct |
30.7 ppb | 0.4 | — | — | — | — | — | 77× over |
| Dibromoacetic acid Disinfection byproduct |
1.88 ppb | 0.03 | — | — | — | — | — | 63× over |
| Dichloroacetic acid Disinfection byproduct |
10.1 ppb | 0.2 | — | — | — | — | — | 51× over |
| Perfluorooctanoic acid (PFOA) PFAS |
3.12 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 35× over |
| Radium, combined (-226 and -228) Radiological |
0.6 pCi/L | 0.05 | 5.0 | — | — | — | — | 12× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
1.98 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 6.6× over |
| Perfluoropentane sulfonic acid (PFPeS) PFAS |
6.32 ppt | 1.0 | — | — | — | — | — | 6.3× over |
| Nitrate Inorganic |
0.328 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.3× over |
| Chromium (hexavalent) Heavy metal |
0.0384 ppb | 0.02 | — | — | — | — | — | 1.9× over |
| Bromoform Disinfection byproduct |
0.65 ppb | 0.5 | — | — | — | — | — | 1.3× over |
| 4:2 Fluorotelomer sulfonate (4:2 FTS) Other |
0.875 ppt | 1.0 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
177.4 ppb | 210.0 | — | — | — | — | — | Below guideline |
| 6:2 Fluorotelomer sulfonate (6 2FTS) Other |
0.738 ppt | 1.0 | — | — | — | — | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.225 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Molybdenum Other |
2.64 ppb | 40.0 | — | — | — | — | — | Below guideline |
| 1,1-Dichloroethane Volatile organic compound |
0.133 ppb | 3.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
25.0 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Manganese Heavy metal |
2.46 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Vanadium Other |
0.364 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
14.0 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
10.3 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
12.1 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
4.35 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.125 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
2.04 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Cobalt Other |
0.0786 ppb | 70.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.927 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chlorodifluoromethane Other |
0.0247 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.55 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Germanium Other |
0.383 ppb | — | — | — | — | — | — | Below guideline |
| Lithium Other |
185.0 ppb | — | — | — | — | — | — | Below guideline |
| o-toluidine Other |
0.00123 ppb | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
SIOUX CITY WATER SUPPLY service area
This water system serves 1 community in Woodbury County, Iowa. Click any city for its dedicated tap water quality page.
Find the right filter for SIOUX CITY water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.