Norwalk, Connecticut Water Quality Report

Comprehensive water safety analysis • Updated February 2026

Norwalk's water meets EPA standards, though 0 contaminant(s) are elevated above 50% of limits.

Water Safety Overview

Generally Safe. Norwalk's tap water meets EPA standards. Score: 88/100.

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9
Total Tested
0
Above EPA Limit
0
Elevated
9
Safe Levels

All Detected Contaminants

9 contaminants tested • EPA SDWIS data

ContaminantLevel DetectedEPA Limit% of LimitStatus
Haloacetic Acids
12.94 ug/L
60.00 ug/L
21.6%
Safe
Fluoride
0.628 mg/L
4.00 mg/L
15.7%
Safe
Lead
0.0022 mg/L
0.015 mg/L
14.3%
Safe
Copper
0.186 mg/L
1.30 mg/L
14.3%
Safe
Nitrate
1.22 mg/L
10.00 mg/L
12.2%
Safe
Arsenic
0.0011 mg/L
0.010 mg/L
10.7%
Safe
Total Trihalomethanes
5.58 ug/L
80.00 ug/L
7.0%
Safe
Nitrite
0.057 mg/L
1.00 mg/L
5.7%
Safe
Chromium
0.0032 mg/L
0.100 mg/L
3.2%
Safe

Detailed Water Quality Analysis for Norwalk

In-depth assessment of your municipal water supply

The water quality in Norwalk, Connecticut has been comprehensively evaluated using data from the EPA's Safe Drinking Water Information System (SDWIS) and local water utility reports. Our analysis examines 9 distinct contaminants across multiple categories including inorganic chemicals, disinfection byproducts, microorganisms, and radionuclides. With an overall quality score of 88 out of 100 (Grade: A-), Norwalk's water supply demonstrates strong compliance with federal drinking water standards.

Water Source and Treatment

Norwalk's primary water system, NORWALK WATER SYSTEM, serves approximately 88,004 residents. The water is sourced from surface water sources such as rivers, lakes, or reservoirs. Surface water typically requires more extensive treatment including coagulation, sedimentation, filtration, and disinfection to remove sediments, organic matter, and pathogens.

Contaminant Profile Overview

Of the 9 contaminants analyzed in Norwalk's water supply, 9 (100%) are present at safe levels below 50% of EPA Maximum Contaminant Levels (MCLs). No contaminants currently exceed EPA safety limits. The most common categories of concern in municipal water supplies include disinfection byproducts formed during the chlorination process, heavy metals like lead that can leach from aging infrastructure, and naturally occurring contaminants like arsenic or radium that vary by geographic region.

Regulatory Compliance Status

Norwalk's water system maintains a clean compliance record with no documented EPA violations. This indicates consistent adherence to federal drinking water standards, proper monitoring and reporting procedures, and effective treatment processes. Continued compliance requires ongoing investment in infrastructure maintenance, regular water quality testing, and adaptation to emerging contaminant concerns.

Infrastructure Considerations

Water quality at the tap can differ from quality at the treatment plant due to distribution system conditions. Homes built before 1986 may have lead service lines or lead solder in plumbing that can contribute to lead exposure. Older galvanized pipes can harbor bacteria and release metals. Running cold water for 30 seconds to 2 minutes before drinking or cooking helps flush stagnant water from pipes. Residents in older homes should consider testing their water directly at the tap to assess any additional contamination from household plumbing, as EPA monitoring typically occurs at distribution points rather than individual residences.

Health Implications of Norwalk Water Quality

Understanding potential health effects for residents

Vulnerable Populations

Certain groups face elevated health risks from water contaminants and should take extra precautions. Pregnant women are particularly vulnerable as contaminants like lead and nitrates can affect fetal development, potentially causing developmental delays and birth defects. Infants and young children are at heightened risk because their developing bodies absorb contaminants more readily and are more susceptible to their effects; lead exposure in children can cause irreversible cognitive impairment and behavioral problems. Elderly individuals and those with compromised immune systems (including cancer patients, organ transplant recipients, and HIV/AIDS patients) are more susceptible to waterborne pathogens and may experience severe illness from microorganisms that healthy adults can tolerate. Individuals with kidney disease should be aware of fluoride and other mineral levels, as impaired kidney function affects the body's ability to filter these substances.

Lead Health Effects

Lead has been detected in Norwalk's water supply. There is no safe level of lead exposure. In children, lead can cause developmental delays, learning difficulties, irritability, weight loss, hearing loss, and seizures. In adults, lead exposure contributes to cardiovascular problems, decreased kidney function, and reproductive issues. Pregnant women exposed to lead can transfer it to their developing fetus, increasing risk of premature birth and reduced growth. Use an NSF 53 certified filter and run cold water before drinking to reduce exposure.

Arsenic Health Effects

Arsenic has been detected in Norwalk's water supply. Long-term arsenic exposure, even at levels near EPA limits, is associated with increased risk of skin, lung, bladder, kidney, and liver cancers. Arsenic exposure can also cause cardiovascular disease, diabetes, and neurological effects. Skin changes like thickening and pigmentation may indicate chronic exposure. Reverse osmosis filtration is highly effective at removing arsenic from drinking water.

Nitrate Health Effects

Elevated nitrate levels in Norwalk's water pose particular risk to infants under six months. Nitrates can cause methemoglobinemia ("blue baby syndrome"), a condition where the blood cannot carry sufficient oxygen. Symptoms include bluish skin color, shortness of breath, and in severe cases, death. Formula-fed infants are at greatest risk. Pregnant women should also limit nitrate exposure. Boiling water does NOT remove nitrates—it actually concentrates them. Reverse osmosis or distillation systems effectively remove nitrates.

General Recommendations

Based on Norwalk's water quality profile, residents should consider the following protective measures: While water quality is generally good, filtration remains beneficial for removing trace contaminants. Always use cold water for drinking and cooking, as hot water can contain higher levels of metals from pipes. Have your home tested if it was built before 1986 to check for lead plumbing. Review your annual Consumer Confidence Report (water quality report) from your utility to stay informed about local water quality trends. Pregnant women, families with young children, and immunocompromised individuals should consult healthcare providers about water safety precautions specific to their situation.

Recommended Water Filters for Norwalk

Based on detected contaminants

Reverse Osmosis System

Best for Norwalk. Removes 95-99% of contaminants including heavy metals, PFAS, and nitrates.

  • ✓ Removes lead
  • ✓ Removes arsenic
  • ✓ Removes nitrates
  • ✓ Removes total dissolved solids

Activated Carbon Filter

Good for Norwalk. Removes chlorine, improves taste, and filters many organic compounds.

  • ✓ Removes chlorine and chloramine
  • ✓ Improves taste and odor
  • ✓ Filters pesticides and VOCs

NSF 53 Lead Certification Required

Lead detected in Norwalk. Ensure any filter is NSF/ANSI 53 certified for lead removal.

Water System Information

NORWALK WATER SYSTEM

PWS ID:
CT865542
Population Served:
88,004
Water Source:
surface
A-88/100

Norwalk Water Quality Score

Based on EPA contaminant data and compliance records

89
Contaminants
89
Compliance
85
Infrastructure

Positive Findings

  • Excellent overall water quality
  • Most contaminants within safe limits
  • No violations in the past 3 years

Protect Your Family's Water

Even with good water quality, many families choose to filter their water for extra peace of mind.

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