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Federal water data

County water report

Lyon County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Lyon County, Nevada.

Water grade

D

Water score

47.3

State rank

#7

of 16

Health violations

10

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

1 water bodies assessed

Monitoring sites

44

12,480 recent measurements

Live streamflow

119%

WALKER RV ABV WEBER RES NR SCHURZ, NV

Water at a glance

Key Water Indicators for Lyon County

EPA SDWIS

Safety Grade

D

Score: 47.3 / 100

EPA SDWIS

Active Violations

10

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

1 bodies assessed

USGS NWIS

Streamflow Snapshot

119% of mean

WALKER RV ABV WEBER RES NR SCHURZ, NV

EPA WQP

Monitoring Sites

44

12,480 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

D

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

47.3/100

Health violations

10

Health-based violations

Violations per 100K served

20.3

Population-normalized SDWIS rate

Editorial analysis

Understanding Lyon County’s Water

Drinking Water Quality Overview

EPA SDWIS

Lyon County's drinking water received a D grade, scoring 47.3 out of 100. Over the past five years, EPA SDWIS records 10 health-based violations — a pattern that public water utilities are required to disclose and correct.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). None of the assessed waterways are listed as impaired (0 of 1 water bodies) across Lyon County's watersheds. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T12:00:00.000-07:00) puts WALKER RV ABV WEBER RES at 183.0 cfs — flowing above its historical average at 119% of mean. 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. Lyon County has moderate coverage with 44 active monitoring sites with 12,480 recent measurements on record. Predominant monitoring categories include inorganics, minor, metals and physical. 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 Lyon County

Water Verdict

Lyon County receives a below-average water quality assessment with a grade of D and a score of 47.3 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking.

Violation Context

Lyon County has recorded 10 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 20.3 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Lyon County's drinking-water compliance is below average with a Grade D, indicating repeated or unresolved violations in the recent record. Lyon County's drinking-water compliance score is 47.3 out of 100. The violation rate for Lyon County is 20.3 per 100,000 people served. Residents are encouraged to use an NSF 53 or NSF 58-certified filter for drinking and cooking water until the underlying violations are resolved. Running tap water for 30 seconds before use and avoiding older lead-pipe connections can also reduce exposure risk. The current Consumer Confidence Report from your utility will specify the contaminants of concern. With 44 active water-quality monitoring sites in Lyon County, data coverage is strong. A pipeline streamflow snapshot from the WALKER RV ABV WEBER RES gauge is also available on this page.

Regional Context

Lyon County has water quality close to the average county in Nevada. Its water score is within 1.2 points of the state average, meaning its overall water system performance is broadly representative of Nevada as a whole.

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 Lyon County's water environment

Official EPA Resources for Lyon County

EPA How's My Waterway

Interactive watershed health data for Lyon County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Lyon County

Consumer Confidence Reports (NV)

Annual water quality reports from utilities in Nevada

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

0.0%

0 of 1 assessed

Mostly healthy

Top Impairment Causes

No specific impairment causes reported for the assessed water bodies in this county.

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state; counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

44

Active in the past 5 years

Measurements Recorded

12K

12,480 total readings

Most Measured

  • Inorganics, Minor, Metals
  • Physical
  • Inorganics, Major, Non-metals

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

183cfs

May 14, 7:00 PM UTC

vs Long-Term Average

119%

Above typical

Primary Streamgage

WALKER RV ABV WEBER RES NR SCHURZ, NV

USGS site
10301600
Drainage area
2,700 sq mi
Long-term mean
154 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

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Lyon 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 Lyon County, Nevada?
Lyon County, Nevada has a drinking-water quality grade of D with a score of 47.3/100, based on EPA SDWIS compliance data. The county has 10 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 Lyon County?
Lyon County has 10 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 healthy are the watersheds in Lyon County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Lyon County's 1 assessed water bodies are classified as impaired (0 impaired). Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in Lyon County?
EPA's Water Quality Portal records 12,480 measurements from 44 monitoring sites in Lyon County over the past five years. The most frequently measured characteristic groups are Inorganics, Minor, Metals, Physical, Inorganics, Major, Non-metals. 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 Lyon County right now?
Lyon County's primary USGS streamgage on the WALKER RV ABV WEBER RES has a pipeline snapshot of 183 cubic feet per second — 119% of the long-term mean of 154.43 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Lyon County water compare to the Nevada average?
Lyon County's SDWIS water quality score of 47.3/100 is lower than the Nevada state average of 48.5. The average water quality grade across Nevada is D, based on data from 16 counties with available SDWIS data.
Is tap water safe to drink in Lyon County?
Based on EPA SDWIS data, Lyon County has a water quality grade of D (47.3/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. 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).
Why does Lyon County have so many water violations?
Lyon County has 10 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.
How does Lyon County rank for water quality in Nevada?
Lyon County ranks #7 out of 16 counties in Nevada by SDWIS water quality score (1 = best). With a score of 47.3/100, it falls in the middle 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

Mineral County

Nevada

D

43.5

Water score

White Pine County

Nevada

C

52.9

Water score

Humboldt County

Nevada

F

38.6

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.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments, state-reported and EPA-finalized.

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 Reviewed by Evan Brooks, Data Editor

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