Johnson County, Kansas
47 ZIP codes · Avg score 47/100 · Grade D · Updated 2026-06-03
Systems across Johnson County's 47 ZIP codes show elevated violation counts — the county's low safety grade reflects that ongoing compliance pattern.
How Johnson County Compares
How Johnson County Compares
Johnson County scores 17 points below the Kansas state average (64/100) and 21 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Johnson County, Kansas
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 10.9 (asthma 9.3%, diabetes 9.5%)
Estimated additional annual cost per homeowner: $779, driven primarily by flood
Infrastructure: 0.275% avg pipe failure probability, 6% of ZIPs at high risk
43.8% of homes built before 1978 (lead paint era)
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $779
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
254,229 housing units in Johnson County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Johnson County
Remediation costs are relatively manageable for most homeowners in Johnson County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Johnson County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Johnson County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | City of Olathe, | 143,014 | 12 |
| 2 | Water District 1 of Johnson Company | 482,000 | 9 |
| 3 | Johnson Company Rwd 7 | 6,457 | 9 |
| 4 | SPRING HILL, CITY OF | 5,694 | 6 |
| 5 | Miami Company Rwd 2 | 10,311 | 3 |
12 total water systems serve Johnson County.
All ZIP Codes in Johnson County
47 ZIP codes tracked in Johnson County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 66021 | Edgerton | 70 | B | 0 | $232K |
| 2 | 66030 | Gardner | 70 | B | 0 | $282K |
| 3 | 66083 | Spring Hill | 67 | C | 3 | $340K |
| 4 | 66019 | Clearview City | 64 | C | 1 | — |
| 5 | 66018 | De Soto | 53 | D | 0 | $380K |
| 6 | 66211 | Leawood | 53 | D | 0 | $589K |
| 7 | 66213 | Overland Park | 53 | D | 0 | $445K |
| 8 | 66214 | Overland Park | 53 | D | 0 | $322K |
| 9 | 66216 | Shawnee | 53 | D | 0 | $325K |
| 10 | 66217 | Shawnee | 53 | D | 0 | $404K |
| 11 | 66219 | Lenexa | 53 | D | 0 | $371K |
| 12 | 66220 | Lenexa | 53 | D | 0 | $554K |
| 13 | 66221 | Overland Park | 53 | D | 0 | $671K |
| 14 | 66223 | Overland Park | 53 | D | 0 | $403K |
| 15 | 66226 | Shawnee | 53 | D | 0 | $387K |
| 16 | 66227 | Lenexa | 53 | D | 0 | $423K |
| 17 | 66282 | Overland Park | 53 | D | 0 | — |
| 18 | 66061 | Olathe | 47 | D | 3 | $337K |
| 19 | 66062 | Olathe | 47 | D | 3 | $343K |
| 20 | 66085 | Stilwell | 45 | D | 0 | $522K |
| 21 | 66204 | Overland Park | 45 | D | 0 | $254K |
| 22 | 66209 | Leawood | 45 | D | 0 | $554K |
| 23 | 66210 | Overland Park | 45 | D | 0 | $345K |
| 24 | 66215 | Lenexa | 45 | D | 0 | $312K |
| 25 | 66218 | Shawnee | 45 | D | 0 | $409K |
| 26 | 66224 | Overland Park | 45 | D | 0 | $626K |
| 27 | 66051 | Olathe | 43 | D | 3 | — |
| 28 | 66063 | Olathe | 43 | D | 3 | — |
| 29 | 66013 | Bucyrus | 40 | D | 0 | $715K |
| 30 | 66031 | New Century | 40 | D | 0 | — |
| 31 | 66113 | Edwardsville | 40 | D | 0 | — |
| 32 | 66201 | Mission | 40 | D | 0 | — |
| 33 | 66202 | Mission | 40 | D | 0 | $264K |
| 34 | 66203 | Shawnee | 40 | D | 0 | $236K |
| 35 | 66205 | Mission | 40 | D | 0 | $342K |
| 36 | 66206 | Leawood | 40 | D | 0 | $634K |
| 37 | 66207 | Overland Park | 40 | D | 0 | $401K |
| 38 | 66208 | Prairie Village | 40 | D | 0 | $419K |
| 39 | 66212 | Overland Park | 40 | D | 0 | $284K |
| 40 | 66222 | Mission | 40 | D | 0 | — |
| 41 | 66225 | Overland Park | 40 | D | 0 | — |
| 42 | 66250 | Shawnee Mission | 40 | D | 0 | — |
| 43 | 66251 | Overland Park | 40 | D | 0 | — |
| 44 | 66276 | Shawnee Mission | 40 | D | 0 | — |
| 45 | 66283 | Overland Park | 40 | D | 0 | — |
| 46 | 66285 | Lenexa | 40 | D | 0 | — |
| 47 | 66286 | Shawnee | 40 | D | 0 | — |
Recommended Buyer Guides for Johnson County
Editorial methodology pairs each documented risk in this county with the buyer category that addresses it, drawing on water-quality detections, housing-stock lead exposure, EPA Radon Zone designation, and FEMA flood and wildfire ratings. NSF-certified options surface where applicable, and products that match the specific contaminant take priority.
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Johnson County, Kansas
Overview
Johnson County in Kansas covers 47 ZIP codes with an average Home Safety Score of D (47/100).
6 of 47 ZIP codes have recorded EPA violations. All violations are monitoring/reporting type.
← Back to Kansas water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.
What You Can Do
Johnson County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
43.8% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.