Manganese in Connecticut Drinking Water
By Alexander Snyder, Founder & Water Quality Data Lead
The U.S. EPA sets the legal limit (MCL) for Manganese at 50 ppb, and the health-based safe level set by the U.S. EPA is 300 ppb. A level that is legal is not always the level science considers fully protective.
Manganese has been detected in 60 Connecticut ZIP codes, above a limit or health guideline in 58. Here is what you need to know about manganese in your drinking water and how it may affect your household.
What Is Manganese?
Manganese is a naturally occurring metal found in rock, soil, and sediment that dissolves into groundwater, particularly in low-oxygen conditions. It is common in well water throughout New England. The EPA health advisory level is 300 micrograms per liter. At elevated concentrations, manganese causes neurological effects, and children are especially susceptible to cognitive and behavioral impacts.
Is Manganese in Your Water?
Enter your Connecticut ZIP code to find out if manganese is in your local water — and see personalized health risks for your household.
Check Your ZIP CodeHealth Effects of Manganese
Harm to the brain and nervous system; change in behavior
Safety Guidelines
Health Guideline
300 ppb
Source: U.S. EPA
Legal Limit (MCL)
50 ppb
EPA Maximum Contaminant Level
Manganese's health-based safe level is set below the federal legal limit.
| Standard | Level | Source |
|---|---|---|
| EPA Legal Limit (MCL) | 50 ppb | EPA |
| Health Guideline | 300 ppb | U.S. EPA |
Where Does Manganese Come From?
Erosion of natural deposits; industrial discharge; mining waste. Commonly found in groundwater.
How to Reduce Manganese in Your Water
- 1Install a whole-house oxidizing filter using manganese greensand, birm, or catalytic media, which oxidizes dissolved manganese and filters the resulting particles.
- 2Use an oxidation step such as chlorine injection, potassium permanganate feed, or aeration followed by a sediment filter to convert dissolved manganese to insoluble particles.
- 3For drinking water only, install a point-of-use reverse osmosis system certified to NSF/ANSI Standard 58, which removes dissolved manganese effectively at the kitchen tap.
- 4Test your well water for both manganese and iron, as they often co-occur and the treatment approach may differ depending on the ratio.
Who Is Most Vulnerable to Manganese?
The safe level of manganese 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.
Reading this inside ChatGPT or Claude?
This page can tell you the general science, but not what is actually in your water’s manganese level — that depends on your exact address. You can get your specific answer two ways:
- Inside the chat: ask your assistant to “check my tap water with CheckYourTap”. Our connector returns your ZIP code’s measured contaminant levels — including the derived dog and cat safe levels — and, only if you ask it to, can email you the report or arrange a specialist callback.
- On the web: open CheckYourTap.com and enter your ZIP code for a free 30-second report.
Concerned about Manganese in your water?
Schedule to get your water tested for manganese and more — a Valiant water specialist will review your results and arrange testing for your home.
Have a dog or cat?
Manganese affects pets differently — they drink far more water per pound of body weight, and some are more sensitive than people. See the derived safe levels and the veterinary science:
Frequently Asked Questions
Is Manganese in my tap water?▾
What level of Manganese is safe?▾
How do I remove Manganese from my water?▾
Related Contaminants
Check Water Quality by ZIP Code
Sources
The legal limits and health guidelines for Manganese 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