Thallium in Drinking Water
Reference information plus historical EPA compliance records associated with thallium.
EPA Limit (MCL)
2 ppb
EPA Goal (MCLG)
0.5 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
Hair loss, kidney, intestine, liver problems
Common Sources
Electronics, drugs, alloys, glass manufacturing
Treatment Considerations for Thallium
Commonly cited treatment approaches include: Ion exchange, activated alumina. 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.
10,442
Historical Violation Records
6,403
Systems With Records
Historical Thallium Records by State
| State | Records | Systems |
|---|---|---|
| Pennsylvania | 2,072 | 1,028 |
| Washington | 1,664 | 1,087 |
| North Carolina | 919 | 606 |
| Alaska | 659 | 279 |
| Arizona | 495 | 324 |
| Ohio | 464 | 347 |
| Utah | 456 | 245 |
| Oregon | 267 | 227 |
| Colorado | 267 | 171 |
| New Jersey | 262 | 182 |
| Texas | 260 | 96 |
| Connecticut | 253 | 152 |
| Iowa | 231 | 196 |
| Montana | 204 | 134 |
| Virginia | 187 | 150 |
| West Virginia | 183 | 86 |
| California | 173 | 53 |
| Kentucky | 132 | 87 |
| Kansas | 122 | 48 |
| Tennessee | 117 | 86 |
Systems With the Most Thallium Violation Records
RIDGEFIELD PUBLIC WORKS
VALLEY ESTATES
RIVERSIDE CSA #122-MESA VERDE
LEISURE MOUNTAIN MHP
CITY OF DAVIS
HUMPHREY, CITY OF
PA AMERICAN AUDUBON
SEVEN ESTATES
HALCYON WATER SYSTEM
NOTTINGHAM MANOR M H COURT
Frequently Asked Questions
What is Thallium and why can it appear in drinking-water records?
Thallium can be associated with drinking water through: Electronics, drugs, alloys, glass manufacturing.
What reference value does this page show?
The summarized EPA Maximum Contaminant Level is 2 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.