o-Toluidine in Connecticut Drinking Water
By Alexander Snyder, Founder & Water Quality Data Lead
The health-based safe level for o-Toluidine, set by the U.S. EPA, is 0.001 mg/L. This health-protective guideline is typically stricter than federal legal limits, which have not always been updated to reflect current science.
o-Toluidine has been tracked across Connecticut drinking water. Here is what you need to know about o-toluidine in your drinking water and how it may affect your household.
What Is o-Toluidine?
o-Toluidine is an aromatic amine used in industrial dye production and chemical manufacturing. It enters water through discharge from dye plants, chemical facilities, and contaminated industrial sites. The California public health goal is 1 part per billion. o-Toluidine is classified as a known human carcinogen, with bladder cancer as the primary concern. It can also cause methemoglobinemia and liver damage at elevated exposures.
Is o-Toluidine in Your Water?
Enter your Connecticut ZIP code to find out if o-toluidine is in your local water — and see personalized health risks for your household.
Check Your ZIP CodeHealth Effects of o-Toluidine
Bladder cancer, methemoglobinemia, liver damage
Safety Guidelines
Health Guideline
0.001 mg/L
Source: U.S. EPA
o-Toluidine's health-based safe level is set below the federal legal limit.
| Standard | Level | Source |
|---|---|---|
| Health Guideline | 0.001 mg/L | U.S. EPA |
Where Does o-Toluidine Come From?
Industrial dye production, contaminated sites
How to Reduce o-Toluidine in Your Water
- 1Install a point-of-use activated carbon block filter certified to NSF/ANSI Standard 53 for organic contaminant reduction; activated carbon effectively adsorbs aromatic amines.
- 2A reverse osmosis system certified to NSF/ANSI Standard 58 provides an additional treatment barrier for o-toluidine and related organic compounds.
- 3For whole-house treatment, use a granular activated carbon system at the point of entry to reduce exposure from all water uses.
- 4Test water through a certified laboratory if you live near industrial dye or chemical manufacturing sites, and replace carbon media on the recommended schedule.
Who Is Most Vulnerable to o-Toluidine?
The safe level of o-toluidine varies significantly depending on who is drinking the water. CheckYourTap calculates adjusted safe levels for each member of your household:
A contaminant level that is safe for an adult may exceed guidelines for an infant by 4-8x or more. Check your ZIP code to see personalized results.
Concerned about o-Toluidine in your water?
Schedule to get your water tested for o-toluidine and more — a Valiant water specialist will review your results and arrange testing for your home.
Frequently Asked Questions
Is o-Toluidine in my tap water?▾
What level of o-Toluidine is safe?▾
How do I remove o-Toluidine from my water?▾
Related Contaminants
Check Water Quality by ZIP Code
Sources
The legal limits and health guidelines for o-Toluidine on this page come from the following public authorities:
About This Report
This water quality report is compiled from public records filed with the U.S. Environmental Protection Agency, state health departments, and the U.S. Geological Survey. Contaminant levels are evaluated against EPA federal standards and health-based guidelines from leading environmental and public health organizations. CheckYourTap is a service of Valiant Energy Solutions, a Connecticut water quality and energy services company established in 1930.
This report is general information, not medical advice or a substitute for certified laboratory testing. Talk to your pediatrician or physician about specific health concerns.
Reviewed by the CheckYourTap editorial team. Last updated July 2026