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County water report

North Slope Borough Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for North Slope Borough, Alaska.

Water grade

C

Water score

53.7

State rank

#3

of 22

Health violations

1

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

1 water bodies assessed

Monitoring sites

41

3,447 recent measurements

Live streamflow

955%

COLVILLE R AT UMIAT AK

Water at a glance

Key Water Indicators for North Slope Borough

EPA SDWIS

Safety Grade

C

Score: 53.7 / 100

EPA SDWIS

Active Violations

1

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

1 bodies assessed

USGS NWIS

Streamflow Snapshot

955% of mean

COLVILLE R AT UMIAT AK

EPA WQP

Monitoring Sites

41

3,447 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

C

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

53.7/100

Health violations

1

Health-based violations

Violations per 100K served

11.6

Population-normalized SDWIS rate

Editorial analysis

Understanding North Slope Borough’s Water

Drinking Water Quality Overview

EPA SDWIS

North Slope Borough's drinking water earned a C grade, scoring 53.7 out of 100. Over the past five years, EPA SDWIS records 1 health-based violation — a single incident worth monitoring.

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 North Slope Borough'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 2025-06-21T03:30:00.000-08:00) puts COLVILLE R at 99.4k cfs — running significantly above its long-term average at 955% of mean flow. 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. North Slope Borough has moderate coverage with 41 active monitoring sites with 3,447 recent measurements on record. Predominant monitoring categories include physical and inorganics, minor, metals. 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 North Slope Borough

Water Verdict

North Slope Borough receives a below-average water quality assessment with a grade of C and a score of 53.7 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking.

Violation Context

North Slope Borough has recorded 1 health-based violation, meaning the water system experienced at least one exceedance of federal contaminant limits or treatment requirements. At 11.6 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Tap water in North Slope Borough meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. North Slope Borough's drinking-water compliance score is 53.7 out of 100. The violation rate for North Slope Borough is 11.6 per 100,000 people served. Residents who are immunocompromised, pregnant, or have young children may benefit from using an NSF 53-certified filter. Contacting your local utility for the current Consumer Confidence Report will confirm which specific violations were recorded and whether they have been resolved. With 41 active water-quality monitoring sites in North Slope Borough, data coverage is strong. A pipeline streamflow snapshot from the COLVILLE R gauge is also available on this page.

Regional Context

North Slope Borough has better water quality than the average county in Alaska. Its water score is 33.9 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 North Slope Borough's water environment

Official EPA Resources for North Slope Borough

EPA How's My Waterway

Interactive watershed health data for North Slope Borough

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for North Slope Borough

Consumer Confidence Reports (AK)

Annual water quality reports from utilities in Alaska

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

41

Active in the past 5 years

Measurements Recorded

3.4K

3,447 total readings

Most Measured

  • Physical
  • Inorganics, Minor, Metals
  • Nutrient

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

99.4Kcfs

Jun 21, 11:30 AM UTC

vs Long-Term Average

955%

Well above typical

Primary Streamgage

COLVILLE R AT UMIAT AK

USGS site
15875000
Drainage area
13,860 sq mi
Long-term mean
10.4K 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.

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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 North Slope Borough: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 North Slope Borough, Alaska?
North Slope Borough, Alaska has a drinking-water quality grade of C with a score of 53.7/100, based on EPA SDWIS compliance data. The county has 1 health-based drinking water violation over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in North Slope Borough?
North Slope Borough has 1 health-based drinking water violation 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 North Slope Borough?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of North Slope Borough'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 North Slope Borough?
EPA's Water Quality Portal records 3,447 measurements from 41 monitoring sites in North Slope Borough over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Minor, Metals, Nutrient. 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 North Slope Borough right now?
North Slope Borough's primary USGS streamgage on the COLVILLE R has a pipeline snapshot of 99,400 cubic feet per second — 955% of the long-term mean of 10,411.05 cfs. This is well above typical — often a signal of recent precipitation or storm runoff. For the latest gauge feed, visit waterdata.usgs.gov.
How does North Slope Borough water compare to the Alaska average?
North Slope Borough's SDWIS water quality score of 53.7/100 is higher than the Alaska state average of 19.8. The average water quality grade across Alaska is F, based on data from 22 counties with available SDWIS data.
Is tap water safe to drink in North Slope Borough?
Based on EPA SDWIS data, North Slope Borough has a water quality grade of C (53.7/100). This indicates moderate compliance. Some violations have been recorded but overall standards are maintained. 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 North Slope Borough have clean drinking water?
North Slope Borough has 1 health-based drinking water violation according to EPA records. With a water quality score of 53.7/100 and grade C, 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 North Slope Borough rank for water quality in Alaska?
North Slope Borough ranks #3 out of 22 counties in Alaska by SDWIS water quality score (1 = best). With a score of 53.7/100, 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

Anchorage Municipality

Alaska

C

52.4

Water score

Fairbanks North Star Borough

Alaska

D

47.8

Water score

Juneau City and Borough

Alaska

C

62.0

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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