Kootenai County Water Quality: 4 Cities Ranked by the Records

Name: Kootenai County Water Quality Data (2026)
Creator: PurityMap
License: https://creativecommons.org/licenses/by/4.0/

Kootenai County, Idaho: 4 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my system Open on the map Private wells in Kootenai County

Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

Lead (90th percentile)Detected in 2 systems of 4 tested15 µg/L federal action level · US EPAHighest2 µg/L

COEUR D ALENE CITY OF2 µg/LMonitoring period: 2023–2025
POST FALLS CITY OF1 µg/LMonitoring period: 2023–2025
HAYDEN LAKE IRRIGATION DISTNot detectedMonitoring period: 2023–2025
RATHDRUM CITY OFNot detectedMonitoring period: 2024–2026 (still open)

Perfluorohexanoic acid (PFHxA)Detected in 1 system of 4 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest4.2 ng/L

RATHDRUM CITY OF4.2 ng/LSample date: 2024-02-13 to 2024-08-07
COEUR D ALENE CITY OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-05-12 to 2025-12-01
HAYDEN LAKE IRRIGATION DISTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-12 to 2024-06-26
POST FALLS CITY OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-16 to 2023-09-27

Perfluoropentanoic acid (PFPeA)Detected in 2 systems of 4 testedNo federal or state limit; shown for transparencyHighest8 ng/L

RATHDRUM CITY OF8 ng/LSample date: 2024-02-13 to 2024-08-07
COEUR D ALENE CITY OF3.4 ng/LSample date: 2025-05-12 to 2025-12-01
HAYDEN LAKE IRRIGATION DISTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-12 to 2024-06-26
POST FALLS CITY OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-16 to 2023-09-27

28 substances tested, none detected in any systemShow

Tested in these 4 systems: COEUR D ALENE CITY OF, HAYDEN LAKE IRRIGATION DIST, POST FALLS CITY OF, RATHDRUM CITY OF

11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
Lithium
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
Perfluoro-3-methoxypropanoic acid (PFMPA)
Perfluoro-4-methoxybutanoic acid (PFMBA)
Perfluorobutanesulfonic acid (PFBS)
Perfluorobutanoic acid (PFBA)
Perfluorodecanoic acid (PFDA)
Perfluorododecanoic acid (PFDoA)
Perfluoroheptanesulfonic acid (PFHpS)
Perfluoroheptanoic acid (PFHpA)
Perfluorohexanesulfonic acid (PFHxS)
Perfluorononanoic acid (PFNA)
Perfluorooctanesulfonic acid (PFOS)
Perfluorooctanoic acid (PFOA)
Perfluoropentanesulfonic acid (PFPeS)
Perfluorotetradecanoic acid (PFTA)
Perfluorotridecanoic acid (PFTrDA)
Perfluoroundecanoic acid (PFUnA)

4 cities

Cities ranked by the records

1
RathdrumRATHDRUM CITY OF
PFAS detected, within limit
Open city report →
2
HaydenHAYDEN LAKE IRRIGATION DIST
No PFAS detected
Open city report →
3
Coeur D'AleneCOEUR D ALENE CITY OF
PFAS detected, within limitLead below action level
Open city report →
4
Post FallsPOST FALLS CITY OF
No PFAS detectedLead below action level
Open city report →

Showing 4 of 4 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in Kootenai CountyPFAS detected in 2 of 4 cities; none had a sample above a 2024 EPA limit

4.0 ng/L federal MCL · PFOS, ng/LPFAS in Idaho

Lead

0of 4 cities above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in Idaho

Who supplies the county

Largest water systems

Coeur D'AleneCOEUR D ALENE CITY OF · ID1280053
54,115 served
Post FallsPOST FALLS CITY OF · ID1280147
20,285 served
RathdrumRATHDRUM CITY OF · ID1280152
10,358 served
HaydenHAYDEN LAKE IRRIGATION DIST · ID1280087
9,375 served

Questions

Frequently asked

How does Kootenai County tap water compare across cities?

PurityMap ranks 4 cities in Kootenai County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Rathdrum's main water system: RATHDRUM CITY OF · PWSID ID1280152 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Kootenai County cities had a PFAS sample above a 2024 EPA limit?

None of the 4 Kootenai County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing. PFAS were detected below the limit in 2.

Is there lead in Kootenai County tap water?

Utilities report lead as a 90th-percentile result from home taps. 2 of 4 Kootenai County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

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