Cyanide in Drinking Water
Reference information plus historical EPA compliance records associated with cyanide.
EPA Limit (MCL)
200 ppb
EPA Goal (MCLG)
200 ppb
Category
Inorganic
Regulatory values are a concise reference, not legal or medical advice. Confirm the current standard and rule-specific details on EPA.gov.
Health Effects
Nerve damage, thyroid problems
Common Sources
Discharge from steel/metal and plastic factories
Treatment Considerations for Cyanide
Commonly cited treatment approaches include: Reverse osmosis, ion exchange. Choose treatment only after a certified water test identifies the substance and concentration; verify NSF/ANSI certification and consult a qualified local professional when needed.
4,611
Historical Violation Records
2,925
Systems With Records
Historical Cyanide Records by State
| State | Records | Systems |
|---|---|---|
| Pennsylvania | 1,139 | 640 |
| Washington | 889 | 507 |
| North Carolina | 338 | 275 |
| Alaska | 304 | 148 |
| Oregon | 261 | 205 |
| Connecticut | 221 | 148 |
| West Virginia | 186 | 87 |
| Vermont | 167 | 104 |
| Utah | 159 | 103 |
| Ohio | 118 | 102 |
| Arizona | 94 | 42 |
| Kentucky | 64 | 53 |
| Texas | 53 | 34 |
| Illinois | 52 | 37 |
| Georgia | 46 | 39 |
| New Jersey | 42 | 14 |
| Arkansas | 40 | 27 |
| Missouri | 38 | 34 |
| Puerto Rico | 37 | 28 |
| New Hampshire | 37 | 34 |
Systems With the Most Cyanide Violation Records
RIDGEFIELD PUBLIC WORKS
PA AMERICAN AUDUBON
COAL MOUNTAIN WATER
MOA MUNICIPALITY OF ANCHORAGE
HIAWATHA WATER
NOTTINGHAM MANOR M H COURT
WASHINGTON TOWNSHIP MUA
BRIAN HEAD TOWN WATER SYSTEM
BELLA VISTA CITY WATER SYSTEM
SCOTTSDALE CITY OF
Frequently Asked Questions
What is Cyanide and why can it appear in drinking-water records?
Cyanide can be associated with drinking water through: Discharge from steel/metal and plastic factories.
What reference value does this page show?
The summarized EPA Maximum Contaminant Level is 200 ppb. Some substances use action levels or rule-specific thresholds instead, so verify the current EPA standard.
Does a historical violation record mean it is in my tap today?
No. A compliance record may be historical or resolved. Use the latest Consumer Confidence Report or a certified test for current local conditions.