Tap Water Quality Report
Tap water quality in SIOUX CITY, Iowa
Tap water in SIOUX CITY, Iowa receives a grade of F (49/100) from TapWaterSafety.org. It's served by SIOUX CITY WATER SUPPLY. 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. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in SIOUX CITY's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving SIOUX CITY.
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.
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.
Recommended filters for SIOUX CITY
Filters matched to the specific contaminants in SIOUX CITY's 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.
All contaminants detected in SIOUX CITY's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. 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, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from SIOUX CITY WATER SUPPLY.