County water report

Johnson County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Johnson County, Kansas.

Water grade

Water score

71.3

State rank

#35

of 105

Health violations

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

2,917 recent measurements

Live streamflow

30%

KANSAS R NR LAKE QUIVIRA, KS

Water at a glance

Key Water Indicators for Johnson County

EPA SDWIS

Safety Grade

Score: 71.3 / 100

EPA SDWIS

Active Violations

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

30% of mean

KANSAS R NR LAKE QUIVIRA, KS

EPA WQP

Monitoring Sites

2,917 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

71.3/100

Health violations

Health-based violations

Violations per 100K served

0.4

Population-normalized SDWIS rate

Data center water stress

Johnson County has 10 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #45 nationally by combining its water score with mapped data center density.

DCWSI

77.3

0-100 index

Facility count

86.3 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+21.3

Compared with US county median

Named operators

DataBankTierPoint

Mapped facilities

CLOP OLATHE - 10MW DATA CENTER (AIR)
OLATHE
EPA ECHO
Data Center Lenexa
Lenexa
OSM
DATABANK LTD MCI 3 (AIR)
LENEXA · DataBank
EPA ECHO
NETRALITY DATA CENTERS - KC2 (AIR)
SHAWNEE
EPA ECHO
OpenStreetMap data center 1024384322
Lenexa
OSM
OpenStreetMap data center 1392657385
Olathe
OSM

4 more mapped facilities included in the county score.

See the Johnson County data-center report Review methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in Johnson County.

Facility size: 100 MW

1 MW1,000 MW

Cooling type

Utilization: 70%

40%100%

799K gallons/dayHigh Impact

Your facility would use 59.9% of this county's industrial water baseline. Verify water rights and long-term drought projections before committing.

59.9% of county industrial baseline0.54 Mgal/day remaining headroom

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding Johnson County’s Water

Drinking Water Quality Overview

EPA SDWIS

Johnson County earns an A grade for drinking water quality, scoring 71.3 out of 100. Over the past five years, EPA SDWIS records 3 health-based violations — a small cluster that warrants attention.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T13:45:00.000-05:00) puts KANSAS R at 2.2k cfs — well below its long-term average at 30% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Johnson County has moderate coverage with 30 active monitoring sites with 2,917 recent measurements on record. Predominant monitoring categories include organics, pesticide and biological, counts. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for Johnson County

Water Verdict

Johnson County, Kansas receives a good water quality assessment with a grade of A and a score of 71.3 out of 100. While the water supply is generally safe, occasional monitoring gaps or minor contaminant detections may occur. The county's primary USGS gauge drains roughly 59,985 square miles of upstream watershed, giving local source waters a regional footprint. At the most recent USGS reading, local streamflow was below its historical mean at 30.4% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Johnson County, Kansas show 3 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 0.4 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. For independent context, 2,917 water-quality monitoring results have been recorded across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in Johnson County earns a Grade A overall with a small number of isolated health violations in the recent record. Johnson County's drinking-water compliance score is 71.3 out of 100. The violation rate for Johnson County is 0.4 per 100,000 people served. These violations were likely resolved quickly; Grade A reflects a strong multi-year compliance trend. Reviewing the most recent Consumer Confidence Report will show exactly which systems were affected and what corrective action was taken. With 30 active water-quality monitoring sites in Johnson County, data coverage is strong. A pipeline streamflow snapshot from the KANSAS R gauge is also available on this page.

Regional Context

Johnson County has better water quality than the average county in Kansas. Its water score is 28.7 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Johnson County's water environment

Official EPA Resources for Johnson County

EPA How's My Waterway

Interactive watershed health data for Johnson County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Johnson County

Consumer Confidence Reports (KS)

Annual water quality reports from utilities in Kansas

Past 5 years

Water Quality Monitoring

Monitoring Sites

Active in the past 5 years

Measurements Recorded

2.9K

2,917 total readings

Most Measured

Organics, Pesticide
Biological, Counts
Physical

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

2,220cfs

May 14, 6:45 PM UTC

vs Long-Term Average

30%

Well below typical

Primary Streamgage

KANSAS R NR LAKE QUIVIRA, KS

USGS site: 06892518
Drainage area: 59,985 sq mi
Long-term mean: 7,312 cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

Water Cost Estimate

Household size

3 people · ~225 gal/day

Filter type

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Johnson County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

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Frequently Asked Questions

What is the water quality in Johnson County, Kansas?

Johnson County, Kansas has a drinking-water quality grade of A with a score of 71.3/100, based on EPA SDWIS compliance data. The county has 3 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.

Are there any water violations in Johnson County?

Johnson County has 3 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.

How much water-quality monitoring happens in Johnson County?

EPA's Water Quality Portal records 2,917 measurements from 30 monitoring sites in Johnson County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Biological, Counts, Physical. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.

What's happening with rivers in Johnson County right now?

Johnson County's primary USGS streamgage on the KANSAS R has a pipeline snapshot of 2,220 cubic feet per second — 30% of the long-term mean of 7,312.1 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.

How does Johnson County water compare to the Kansas average?

Johnson County's SDWIS water quality score of 71.3/100 is higher than the Kansas state average of 42.6. The average water quality grade across Kansas is D, based on data from 105 counties with available SDWIS data.

Is tap water safe to drink in Johnson County?

Based on EPA SDWIS data, Johnson County has a water quality grade of A (71.3/100). This indicates good to excellent water quality with strong SDWIS compliance. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).

Does Johnson County have clean drinking water?

Johnson County has 3 health-based drinking water violations according to EPA records. With a water quality score of 71.3/100 and grade A, the county's drinking water has had some compliance issues but continues to be monitored. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.

How does Johnson County rank for water quality in Kansas?

Johnson County ranks #35 out of 105 counties in Kansas by SDWIS water quality score (1 = best). With a score of 71.3/100, it falls in the top third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Saline County

Kansas

67.8

Water score

Riley County

Kansas

65.6

Water score

Neosho County

Kansas

60.8

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Evan Brooks, Data EditorUpdated May 14, 2026Reviewed by Evan Brooks, Data Editor

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