City water profile

Water hardness in Koyuk

Find official utility reports, understand hardness, and check the water system serving your home in Koyuk, Alaska.

Utility-reported hardness

Not yet available

Check your provider and source →

State comparison: Unavailable
Evidence comparison rank: —
Matched utilities: 1
Active health records: 0

Your tap water

What does the utility report?

Match the utility name to your water bill. These results describe the utility’s water, not a test at your home. A ZIP can include several water systems.

Utility hardness unavailable in this index

Nearby river or groundwater samples cannot tell us the hardness coming out of your tap. Ask your water provider for total hardness as CaCO₃, or test it at home.

Find an official utility report →

Convert a hardness result →Test your tap →

Match the name on your water bill

Your utility’s measurements and compliance records

These are possible serving systems. A record for one system does not apply to every home in this ZIP. Confirm your provider before interpreting a measurement or notice. Federal records can lag current utility notices.

EPA snapshot: 2026Q2. Historical window begins Jan 1, 2021.

Koyuk Public Water System

AK2340167 · Groundwater influenced by surface water · 277 people served system-wide

The system names this served city; Census place overlap links the city to this ZCTA.

No active health-based record in this imported snapshot

Find this utility’s official report →

Measurements (1)

An action level is a regulatory trigger, not a pass/fail health boundary. A reported zero is the value in the source record and does not establish that lead is absent at your tap.

Lead (90th percentile)

EPA SDWIS Lead and Copper Rule samples

Below action level

Reported level: 7.0e-4 mg/L
Action level: 0.015 mg/L

5% of the listed benchmark

Monitoring period: Jan 1, 2023 to Dec 31, 2025

Violation history (68)

Imported violation history for Koyuk Public Water System
Rule	Status	Period
Surface Water Treatment Rule	Archived	Mar 1, 2026 to Mar 31, 2026
Surface Water Treatment Rule	Resolved	Jul 1, 2025 to Jul 31, 2025
Revised Total Coliform Rule	Resolved	Jul 1, 2025 to Jul 31, 2025
Chlorine	Resolved	Jul 1, 2025 to Jul 31, 2025
Chlorine	Resolved	May 1, 2025 to May 31, 2025
Revised Total Coliform Rule	Resolved	May 1, 2025 to May 31, 2025
Surface Water Treatment Rule	Resolved	May 1, 2025 to May 31, 2025
Surface Water Treatment Rule	Resolved	Nov 1, 2024 to Nov 30, 2024
Chlorine	Resolved	Nov 1, 2024 to Nov 30, 2024
Revised Total Coliform Rule	Resolved	Nov 1, 2024 to Nov 30, 2024
LEAD AND COPPER RULE REVISIONS	Resolved	Oct 17, 2024 to Jun 11, 2025
LEAD AND COPPER RULE REVISIONSHealth-based	Resolved	Oct 17, 2024 to Jun 11, 2025
Interim Enhanced Surface Water Treatment Rule	Resolved	Oct 1, 2024 to Oct 31, 2024
Surface Water Treatment Rule	Resolved	Oct 1, 2024 to Oct 31, 2024
Interim Enhanced Surface Water Treatment Rule	Resolved	Apr 1, 2024 to Apr 30, 2024
Surface Water Treatment RuleHealth-based	Resolved	Apr 1, 2024 to Apr 30, 2024
Chlorine	Resolved	Jul 1, 2023 to Aug 7, 2023
Revised Total Coliform Rule	Resolved	Jul 1, 2023 to Jul 31, 2023
Consumer Confidence Rule	Resolved	Jul 1, 2023 to Jul 13, 2023
Surface Water Treatment Rule	Resolved	Jul 1, 2023 to Jul 31, 2023
Chlorine	Resolved	Apr 1, 2023 to May 8, 2023
Revised Total Coliform Rule	Resolved	Apr 1, 2023 to Apr 30, 2023
Surface Water Treatment Rule	Resolved	Apr 1, 2023 to Apr 30, 2023
Revised Total Coliform Rule	Resolved	Mar 1, 2023 to Mar 31, 2023
Surface Water Treatment Rule	Resolved	Mar 1, 2023 to Mar 31, 2023
Chlorine	Resolved	Jan 1, 2023 to Mar 31, 2023
Revised Total Coliform Rule	Resolved	Nov 1, 2022 to Nov 30, 2022
Surface Water Treatment Rule	Resolved	Nov 1, 2022 to Nov 30, 2022
Surface Water Treatment RuleHealth-based	Resolved	Oct 1, 2022 to Oct 31, 2022
Chlorine	Resolved	Oct 1, 2022 to Dec 7, 2022
Surface Water Treatment RuleHealth-based	Resolved	Jul 1, 2022 to Jul 31, 2022
Interim Enhanced Surface Water Treatment Rule	Resolved	Apr 1, 2022 to Apr 30, 2022
Interim Enhanced Surface Water Treatment Rule	Resolved	Mar 1, 2022 to Mar 31, 2022
Interim Enhanced Surface Water Treatment Rule	Resolved	Feb 1, 2022 to Feb 28, 2022
Lead and Copper Rule	Resolved	Jan 1, 2022 to Dec 16, 2022
Nitrate	Resolved	Jan 1, 2022 to Dec 31, 2022
1,2,4-Trichlorobenzene	Resolved	Jan 1, 2022 to Dec 31, 2022
cis-1,2-Dichloroethylene	Resolved	Jan 1, 2022 to Dec 31, 2022
DICHLOROMETHANE	Resolved	Jan 1, 2022 to Dec 31, 2022
p-Dichlorobenzene	Resolved	Jan 1, 2022 to Dec 31, 2022
Vinyl chloride	Resolved	Jan 1, 2022 to Dec 31, 2022
1,2-Dichloroethane	Resolved	Jan 1, 2022 to Dec 31, 2022
Carbon tetrachloride	Resolved	Jan 1, 2022 to Dec 31, 2022
1,2-Dichloropropane	Resolved	Jan 1, 2022 to Dec 31, 2022
Trichloroethylene	Resolved	Jan 1, 2022 to Dec 31, 2022
Tetrachloroethylene	Resolved	Jan 1, 2022 to Dec 31, 2022
Toluene	Resolved	Jan 1, 2022 to Dec 31, 2022
Styrene	Resolved	Jan 1, 2022 to Dec 31, 2022
o-Dichlorobenzene	Resolved	Jan 1, 2022 to Dec 31, 2022
Benzene	Resolved	Jan 1, 2022 to Dec 31, 2022
Ethylbenzene	Resolved	Jan 1, 2022 to Dec 31, 2022
Xylenes, Total	Resolved	Jan 1, 2022 to Dec 31, 2022
1,1-Dichloroethylene	Resolved	Jan 1, 2022 to Dec 31, 2022
CHLOROBENZENE	Resolved	Jan 1, 2022 to Dec 31, 2022
1,1,2-Trichloroethane	Resolved	Jan 1, 2022 to Dec 31, 2022
1,1,1-Trichloroethane	Resolved	Jan 1, 2022 to Dec 31, 2022
trans-1,2-Dichloroethylene	Resolved	Jan 1, 2022 to Dec 31, 2022
Surface Water Treatment Rule	Resolved	Dec 1, 2021 to Dec 31, 2021
Interim Enhanced Surface Water Treatment Rule	Resolved	Dec 1, 2021 to Dec 31, 2021
Revised Total Coliform Rule	Resolved	Nov 1, 2021 to Nov 30, 2021
Revised Total Coliform Rule	Resolved	Oct 1, 2021 to Oct 31, 2021
Revised Total Coliform Rule	Resolved	Sep 1, 2021 to Sep 30, 2021
Surface Water Treatment RuleHealth-based	Resolved	Jul 1, 2021 to Jul 31, 2021
Chlorine	Resolved	Jul 1, 2021 to Sep 30, 2021
Revised Total Coliform Rule	Resolved	Jul 1, 2021 to Jul 31, 2021
Total Haloacetic Acids (HAA5)	Resolved	Mar 1, 2021 to Feb 28, 2022
TTHM	Resolved	Mar 1, 2021 to Feb 28, 2022
Unspecified rule	Unaddressed	Jun 6, 2012

City summary

What the indexed records say

Koyuk has 1 published ZIP profile across Nome Census Area. No qualifying nearby hardness observation is available for the city.

Because only one ZIP is represented, the city median and range are the same local estimate. It should not be read as multiple independent samples across the community.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs

Moderately hard0 ZIPs

Hard0 ZIPs

Very hard0 ZIPs

0 of 1 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance: — miles
Profiles with evidence: 0/1

Confidence labels

High: 0Moderate: 0Low: 0

Observation window: unavailable to unavailable.

ZIP directory

Water reports in Koyuk

Open a ZIP for site-level provenance and measurements.

ZIP code

99753

No estimate

—

Nearest site: — mi
Confidence: —

View full ZIP evidence →

Practical next steps

Move from index to evidence

1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
3. Use a measured hardness result. Confirm health concerns or treatment sizing with the right method.

Continue comparing

Other Alaska communities

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— No median

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— No median

Savoonga

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Search all 131 Alaska cities →

Questions people ask

About water in Koyuk

Is the water hard?

Check the utility-reported result above when available. Nearby environmental samples cannot establish tap-water hardness. Ask your provider or test your tap.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.