Gaithersburg, Maryland Water Quality Report

Comprehensive water safety analysis • Updated February 2026

Gaithersburg maintains excellent water quality with all 8 tested contaminants well below EPA safety limits.

All 1 historical violation(s) in Gaithersburg have been resolved.

Water Safety Overview

Generally Safe. Gaithersburg's tap water meets EPA standards. Score: 93/100.

Want to understand your score better? Learn how scores are calculated →

8
Total Tested
0
Above EPA Limit
0
Elevated
8
Safe Levels

All Detected Contaminants

8 contaminants tested • EPA SDWIS data

ContaminantLevel DetectedEPA Limit% of LimitStatus
Haloacetic Acids
9.97 ug/L
60.00 ug/L
16.6%
Safe
Fluoride
0.577 mg/L
4.00 mg/L
14.4%
Safe
Chromium
0.013 mg/L
0.100 mg/L
12.8%
Safe
Mercury
0.0002 mg/L
0.0020 mg/L
10.6%
Safe
Nitrite
0.087 mg/L
1.00 mg/L
8.7%
Safe
Lead
0.0011 mg/L
0.015 mg/L
7.5%
Safe
Nitrate
0.510 mg/L
10.00 mg/L
5.1%
Safe
Copper
0.039 mg/L
1.30 mg/L
3.0%
Safe

Detailed Water Quality Analysis for Gaithersburg

In-depth assessment of your municipal water supply

The water quality in Gaithersburg, Maryland has been comprehensively evaluated using data from the EPA's Safe Drinking Water Information System (SDWIS) and local water utility reports. Our analysis examines 8 distinct contaminants across multiple categories including inorganic chemicals, disinfection byproducts, microorganisms, and radionuclides. With an overall quality score of 93 out of 100 (Grade: A), Gaithersburg's water supply demonstrates strong compliance with federal drinking water standards.

Water Source and Treatment

Gaithersburg's primary water system, GAITHERSBURG WATER SYSTEM, serves approximately 67,750 residents. The water is sourced from a combination of surface and groundwater sources. Groundwater is generally naturally filtered through soil and rock layers, though it may contain elevated levels of minerals and naturally occurring contaminants like arsenic or radon.

Contaminant Profile Overview

Of the 8 contaminants analyzed in Gaithersburg's water supply, 8 (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

Gaithersburg's water system has a compliance history with 1 documented EPA violation. All historical violations have been addressed and resolved. Violations can range from monitoring and reporting failures to actual exceedances of contaminant limits. Water utilities are required by law to notify customers of any violations that may affect health and to take corrective action to return to compliance.

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 Gaithersburg 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 Gaithersburg'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.

Nitrate Health Effects

Elevated nitrate levels in Gaithersburg'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 Gaithersburg'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 Gaithersburg

Based on detected contaminants

Reverse Osmosis System

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

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

Activated Carbon Filter

Good for Gaithersburg. 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 Gaithersburg. Ensure any filter is NSF/ANSI 53 certified for lead removal.

EPA Compliance History

Past violations for Gaithersburg's water system

MCL

Lead - 2/4/2022

Resolved

Water System Information

GAITHERSBURG WATER SYSTEM

PWS ID:
MD429140
Population Served:
67,750
Water Source:
mixed
A93/100

Gaithersburg Water Quality Score

Based on EPA contaminant data and compliance records

97
Contaminants
94
Compliance
86
Infrastructure

Positive Findings

  • Excellent overall water quality
  • All tested contaminants well below EPA 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.

Affiliate links - we may earn a commission