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EPA SDWIS

North Slope Borough Water Quality

North Slope Borough, Alaska

Water Grade

C

Water Score

53.7

Violations

1

State Rank

#3

of 22 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

53.7/100

Higher = better quality

Health Violations

1

Health-based violations

Violation Rate

11.6%

Systems with violations

Water Advisory: 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 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Tap water in North Slope Borough meets baseline standards, but residents who are immunocompromised or have young children may want to use an NSF-certified water filter as a precaution. With 1 recorded health violation, staying informed about utility communications and boil-water notices is especially important. For long-term peace of mind, request your utility's latest Consumer Confidence Report and consider independent water testing if you have specific health concerns.

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.

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 this county's assessed water bodies.

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; "% of typical" compares the latest reading against that average.

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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 live streamflow 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 is currently reading 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 genuine real-time data, 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, 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 Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

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