waterbycounty
Compiled federal source snapshot

Nevada Water Quality

Drinking water data for all 16 counties.

Avg SDWIS Compliance Index

54.4

Most Common Five-Year SDWIS Compliance Band

A

Counties with Data

16

of 16 total

County water atlas

Nevada water signals by county

A state-level 2.5D view across drinking-water compliance, watershed impairment, monitoring density, and streamflow snapshot context. Pin any county, switch layers, then use the lens controls to compare index ranges, recorded violation rates, or impaired watersheds without leaving the page.

Counties

16

Avg SDWIS index

54.4

Watersheds

0

ATTAINS counties

Monitoring

16

12 fresh USGS snapshots

State atlas layers combine EPA SDWIS health-based violations, EPA ATTAINS 303(d) impairment assessments, EPA Water Quality Portal monitoring sites, and representative USGS NWIS streamflow gauges. Streamflow values appear only for fresh pipeline snapshots, not as a continuously updated stream. County pages include the observation time and year.

Prepared by ByCounty Editorial TeamPublished by WaterByCounty

Multi-source coverage in Nevada

Beyond Drinking Water

EPA SDWIS

16/ 16

counties with drinking-water compliance data

201 health violations statewide (5yr)

EPA ATTAINS

—

No §303(d) assessments yet for Nevada

EPA WQP

578

monitoring sites across 16 counties

139,827 total readings (5yr window)

USGS NWIS

12

counties with a fresh pipeline snapshot

1 above11 below

State atlas notes

What stands out in Nevada

County water quality is not one number. The strongest read comes from comparing drinking-water compliance against watershed impairment, monitoring density, and streamflow context. Use these signals as a starting point, then open any county profile for source-level detail.

Compliance spread

Elko County has the highest value in the published state SDWIS Compliance Index table at 86.2/100, while Pershing County has the lowest at 9.2/100. That is a 77.0 point gap inside one state.

Zero health violations

6

3+ health violations

8

Monitoring hubs

Washoe County101 sitesHumboldt County73 sitesDouglas County68 sites

Lowest flow reads

Eureka County0%Lander County0%Humboldt County0%

Highest fresh streamflow pipeline snapshots: Churchill County (196%, observation 2026), Pershing County (49%, observation 2026), White Pine County (38%, observation 2026). These are source-data observations, not household tap-water conclusions.

All Nevada Counties

CountySDWIS Compliance Index
Elko County86.2
Esmeralda County86.2
Eureka County86.2
Lincoln County86.2
Storey County86.2
White Pine County86.2
Clark County63.8
Lyon County52.2
Humboldt County50.8
Washoe County40.9
Douglas County38.8
Mineral County34.0
Churchill County28.8
Lander County18.4
Nye County16.5
Pershing County9.2

Frequently Asked Questions

Which Nevada county has the highest SDWIS Compliance Index?
Elko County has the highest SDWIS Compliance Index in the published Nevada cohort at 86.2/100. This WaterByCounty relative comparison is not an EPA score and does not establish current conditions for a utility or address.
What does the Five-Year SDWIS Compliance Band mean?
The band is derived only from each county aggregation's recorded health-violation rate per 100,000 people served for the stated five-year source window. It is separate from the relative SDWIS Compliance Index and is not a current determination for a specific utility or address.
Which USGS streamflow records are shown across Nevada?
WaterByCounty has 12 fresh USGS pipeline snapshots in the published Nevada cohort. Each county page shows its observation timestamp and year. A pipeline snapshot is not a continuously updated reading or a tap-water safety measure.
Where can Nevada residents find current official information?
Review the applicable utility's Consumer Confidence Report, active notices, and the state drinking-water agency. WaterByCounty's county-level historical aggregations do not establish the current status of a specific utility, address, private well, or household plumbing system.
What does Water Quality Portal monitoring volume show in Nevada?
The published county records contain 139,827 results from 578 monitoring locations in the site's five-year aggregation. Monitoring volume does not by itself indicate better or worse water quality.

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. The WaterByCounty SDWIS Compliance Index reflects the recorded rate and is not an EPA score.

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.

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