COUNTY REPORT MO

Johnson County, Missouri

8 ZIP codes · Avg score 78/100 · Grade B · Updated 2026-06-03

Within Johnson County, all 8 tracked ZIP codes show above-average drinking water safety — violations are infrequent and typically minor.

How Johnson County Compares

Johnson County78/100
Missouri avg69/100
National avg68/100

How Johnson County Compares

B
County Grade
78/100
Avg Safety Score
8
ZIP Codes
19
Water Systems

Johnson County scores 9 points above the Missouri state average (69/100) and 10 points above the national average (68/100).

Data: EPA SDWIS Last verified: 2026-06-03

B
County Grade
78
Avg Safety Score
8
ZIP Codes
Best ZIP: 64019 (83/100)
Lowest ZIP: 65305 (53/100)
$219K
Median Home Value
$1,375
Avg Remediation (63% of home value)

ZIP Code Risk Map

Water Quality Map: Johnson County, Missouri

Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.

A B C D F

Key Risk Factors

Health risk index: 12.1 (asthma 10.5%, diabetes 9.6%)

Estimated additional annual cost per homeowner: $396, driven primarily by flood

Infrastructure: 0.284% avg pipe failure probability

42.3% of homes built before 1978 (lead paint era)

County Health Indicators vs National Average

Asthma 10.5% (national: 8.9%)
Diabetes 9.6% (national: 10.5%)
Obesity 35.3% (national: 32.4%)

Black markers indicate national averages. Source: CDC PLACES, Census ACS.

Infrastructure Overview

1990
Median Build Year
42.3%
Pre-1978 Housing
28%
Pipe Failure Probability
0%
ZIPs at High Infra Risk
Moderate
Lead Pipe Risk

Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.

Compound Risk Breakdown

Estimated additional annual cost per homeowner: $396

Flood $250/yr
Energy Code Gap $90/yr
Water / Lead $56/yr

Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).

Housing Age Distribution

21,800 housing units in Johnson County

Pre-1940 9%
1940–1959 8%
1960–1979 20%
1980–1999 31%
2000+ 32%

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

$219K
Median Home Value
$1,375
Est. Remediation Cost
0.6%
of Home Value
Remediation as % of home value low burden

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

Asthma 10.5% (US avg: 8.9%)
Diabetes 9.6% (US avg: 11%)
Obesity 35.3% (US avg: 32.4%)

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 Johnson County Pwsd 3 4,700 5
2 Johnson County Pwsd 2 12,490 4
3 Johnson County Pwsd 1 3,730 3
4 Mo American Warrensburg 18,500 2
5 Pettis/johnson/saline Pwsd 1 1,000 2

19 total water systems serve Johnson County.

All ZIP Codes in Johnson County

8 ZIP codes tracked in Johnson County.

# ZIP Code City Safety Score Grade Violations Home Value
1 64019 Centerview 83 B 0 $219K
2 64040 Holden 83 B 1 $220K
3 64061 Kingsville 83 B 0 $240K
4 64733 Chilhowee 83 B 0 $197K
5 64761 Leeton 82 B 2 $124K
6 64093 Warrensburg 78 B 1 $228K
7 65336 Knob Noster 78 B 1 $195K
8 65305 Whiteman Air Force Base 53 D 0

Recommended Buyer Guides for Johnson County

Where county records show a lead exceedance or pre-1978 housing concentration, lead-specific filters and test kits move toward the top of the list.

Overview

Johnson County in Missouri covers 8 ZIP codes with an average Home Safety Score of B (78/100).

4 of 8 ZIP codes have recorded EPA violations. All violations are monitoring/reporting type.

← Back to Missouri water quality report

Data Sources

Updated daily.

Frequently Asked Questions

Is water safe in Johnson County?
Johnson County receives a grade of B, indicating generally safe tap water across its 8 ZIP codes.
How many water systems serve Johnson County?
Johnson County is served by 19 public water systems that supply drinking water to residents across 8 ZIP codes.
What is the biggest environmental risk in Johnson County?
The primary environmental risk factor in Johnson County is flood. This contributes to an estimated additional annual cost of $396 per homeowner.
How old are homes in Johnson County?
The median home build year in Johnson County is 1990. 42.3% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does Johnson County compare to Missouri?
Johnson County has an average water safety score of 78/100, which is above the Missouri state average of 69/100.

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