COUNTY REPORT KS

Riley County, Kansas

8 ZIP codes · Avg score 61/100 · Grade C · Updated 2026-06-03

Water systems across Riley County's 8 ZIP codes produce average compliance results overall — pockets with documented violations exist, and the variation between areas makes ZIP-level lookup the most useful tool for residents here.

How Riley County Compares

Riley County61/100
Kansas avg64/100
National avg68/100

How Riley County Compares

C
County Grade
61/100
Avg Safety Score
8
ZIP Codes
13
Water Systems

Riley County scores 3 points below the Kansas state average (64/100) and 7 points below the national average (68/100).

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

C
County Grade
61
Avg Safety Score
8
ZIP Codes
Best ZIP: 66531 (66/100)
Lowest ZIP: 66502 (51/100)
$207K
Median Home Value
$1,813
Avg Remediation (88% of home value)

ZIP Code Risk Map

Water Quality Map: Riley County, Kansas

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: 9.5 (asthma 10.1%, diabetes 7.2%)

Estimated additional annual cost per homeowner: $1,158, driven primarily by flood

Infrastructure: 0.336% avg pipe failure probability, 13% of ZIPs at high risk

58.6% of homes built before 1978 (lead paint era)

County Health Indicators vs National Average

Asthma 10.1% (national: 8.9%)
Diabetes 7.2% (national: 10.5%)
Obesity 26.4% (national: 32.4%)

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

Infrastructure Overview

1976
Median Build Year
58.6%
Pre-1978 Housing
34%
Pipe Failure Probability
13%
ZIPs at High Infra Risk
Low
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: $1,158

Flood $700/yr
Wildfire $263/yr
Energy Code Gap $101/yr

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

Housing Age Distribution

30,879 housing units in Riley County

Pre-1940 9%
1940–1959 13%
1960–1979 24%
1980–1999 23%
2000+ 31%

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 Riley County

$207K
Median Home Value
$1,813
Est. Remediation Cost
0.9%
of Home Value
Remediation as % of home value low burden

Remediation costs are relatively manageable for most homeowners in Riley 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 Riley County residents

Asthma 10.1% (US avg: 8.9%)
Diabetes 7.2% (US avg: 11%)
Obesity 26.4% (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 Riley County ranked by EPA violation count.

# Water System Population Violations
1 Riley Company Rwd 1 2,108 17
2 City of Manhattan, 54,763 8
3 Colonial Gardens Mobile Home Ct 1,200 8
4 Riverchase Mobile Home Park 460 8
5 Konza Valley Water Benefit District 345 8

13 total water systems serve Riley County.

All ZIP Codes in Riley County

8 ZIP codes tracked in Riley County.

# ZIP Code City Safety Score Grade Violations Home Value
1 66531 Riley 66 C 0 $196K
2 66449 Leonardville 65 C 3 $159K
3 66517 Ogden 65 C 0 $150K
4 66505 Manhattan 62 C 2
5 66506 Manhattan 62 C 2
6 66554 Randolph 60 C 6 $241K
7 66503 Manhattan 56 C 2 $325K
8 66502 Manhattan 51 D 2 $218K

Recommended Buyer Guides for Riley County

Below: editorial picks, no sponsored placements.

Overview

Riley County in Kansas covers 8 ZIP codes with an average Home Safety Score of C (61/100).

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

← Back to Kansas water quality report

Data Sources

Updated daily.

Frequently Asked Questions

Is water safe in Riley County?
Riley County receives a grade of C. Some ZIP codes have recorded violations and residents in affected areas may want to test their water.
How many water systems serve Riley County?
Riley County is served by 13 public water systems that supply drinking water to residents across 8 ZIP codes.
What is the biggest environmental risk in Riley County?
The primary environmental risk factor in Riley County is flood. This contributes to an estimated additional annual cost of $1,158 per homeowner.
How old are homes in Riley County?
The median home build year in Riley County is 1976. 58.6% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does Riley County compare to Kansas?
Riley County has an average water safety score of 61/100, which is below the Kansas state average of 64/100.

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