Johnson County Water Quality: 3 Cities Ranked by the Records
Johnson County, Kansas: 3 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.
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.
LithiumDetected in 2 systems of 3 tested10 µg/L EPA health reference level (screening, not a legal limit) · US EPAHighest50.9 µg/L
- WATER DISTRICT 1 OF JOHNSON CO50.9 µg/LSample date: 2024-04-15 to 2026-02-16
- OLATHE, CITY OF20.7 µg/LSample date: 2023-03-06 to 2023-12-26
- GARDNER, CITY OFNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-06-05 to 2024-03-18
Water hardnessDetected in 2 systemsAesthetic, no federal health limit · USGSHighest8.8 gpg
- OLATHE, CITY OF8.8 gpgReporting year: 2025
- WATER DISTRICT 1 OF JOHNSON CO7.9 gpgReporting year: 2026
Lead (90th percentile)Detected in 3 systems15 µg/L federal action level · US EPAHighest11 µg/L
- OLATHE, CITY OF11 µg/LMonitoring period: 2021–2023
- WATER DISTRICT 1 OF JOHNSON CO6.48 µg/LMonitoring period: 2021–2023
- GARDNER, CITY OF3.1 µg/LMonitoring period: 2021–2023
Perfluorobutanoic acid (PFBA)Detected in 1 system of 3 testedNo federal or state limit; shown for transparencyHighest5.3 ng/L
- WATER DISTRICT 1 OF JOHNSON CO5.3 ng/LSample date: 2024-04-15 to 2026-02-16
- GARDNER, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-06-05 to 2024-03-18
- OLATHE, CITY OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-03-06 to 2023-12-26
Perfluoropentanoic acid (PFPeA)Detected in 1 system of 3 testedNo federal or state limit; shown for transparencyHighest3.4 ng/L
- GARDNER, CITY OF3.4 ng/LSample date: 2023-06-05 to 2024-03-18
- OLATHE, CITY OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-06 to 2023-12-26
- WATER DISTRICT 1 OF JOHNSON CONot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-15 to 2026-02-16
27 PFAS tested, none detected in any systemShow
Tested in these 3 systems: GARDNER, CITY OF, OLATHE, CITY OF, WATER DISTRICT 1 OF JOHNSON CO
- 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)
- 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)
- Perfluorodecanoic acid (PFDA)
- Perfluorododecanoic acid (PFDoA)
- Perfluoroheptanesulfonic acid (PFHpS)
- Perfluoroheptanoic acid (PFHpA)
- Perfluorohexanesulfonic acid (PFHxS)
- Perfluorohexanoic acid (PFHxA)
- Perfluorononanoic acid (PFNA)
- Perfluorooctanesulfonic acid (PFOS)
- Perfluorooctanoic acid (PFOA)
- Perfluoropentanesulfonic acid (PFPeS)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluoroundecanoic acid (PFUnA)
Cities ranked by the records
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.
0of 3 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 Kansas2cities report hardness · hardest Olathe, 8.8 gpg
2 of 2 are hard on the USGS scale. An aesthetic measure with no federal health limit.
Hard water explainedLargest water systems
- Overland ParkWATER DISTRICT 1 OF JOHNSON CO · KS2009110490,000 served
- OlatheOLATHE, CITY OF · KS2009115143,014 served
- GardnerGARDNER, CITY OF · KS200910623,942 served
Frequently asked
How does Johnson County tap water compare across cities?
PurityMap ranks 3 cities in Johnson 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 Gardner's main water system: GARDNER, CITY OF · PWSID KS2009106 · Purity Score 97 (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 Johnson County cities had a PFAS sample above a 2024 EPA limit?
None of the 3 Johnson 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 Johnson County tap water?
Utilities report lead as a 90th-percentile result from home taps. 3 of 3 Johnson 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.
Does Johnson County have hard water?
Hardness is published in utility water-quality reports for 2 Johnson County cities on record; the hardest is Olathe at 8.8 grains per gallon. Hardness affects scale and appliances; it is not a health finding.
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