Is Gaithersburg, MD Tap Water Safe to Drink?
Graded C, with 25 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
60.8/100
waterverge.com Gaithersburg, MD — Water Quality Report
Gaithersburg's drinking water received a grade of C (60.8 out of 100), indicating fair water quality. The city's 7 water systems serve approximately 805 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 66 violations on record, including 29 health-based violations. 25 remain unresolved.
What to know about Gaithersburg's water
Gaithersburg ranks #89 out of 107 cities in Maryland for water quality, placing it among the lowest-rated in the state.
Gaithersburg relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Gaithersburg may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 12 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Gaithersburg, MD water safe to drink?
Gaithersburg's drinking water has significant quality concerns based on EPA testing data. With a grade of C (60.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 7 water systems serve approximately 805 residents using groundwater (wells).
Recent water quality updates for Gaithersburg
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Gaithersburg's water quality assessment. Grade: C (60.8/100).
Contaminants: Revised Total Coliform Rule.
Contaminants: LEAD AND COPPER RULE REVISIONS.
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Federal disaster declaration (FEMA DR-4091). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3349). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Gaithersburg's water supply.
Well within EPA limits.
Violation history
Gaithersburg's water system has 66 total violations on record, including 29 health-based violations. 25 remain unresolved. 12 violations were issued in the last 5 years.
Flood & environmental risk
Montgomery County has experienced 8 federally declared disasters since 1971. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Patuxent River, Cattail Creek, Soper Branch, Little Seneca Creek Tributary, Cabin Branch.
Where does Gaithersburg's water come from?
Gaithersburg's drinking water comes from groundwater (wells), supplied by 7 water systems serving approximately 805 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Patuxent River (river), Cattail Creek (river), Soper Branch (river), Little Seneca Creek Tributary (river), Cabin Branch (river).
What Gaithersburg residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Gaithersburg's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Gaithersburg's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Gaithersburg
Industrial polluters nearby
Reported releases to surface water by facilities near Gaithersburg, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
SCHUSTER CONCRETE READY MIX LLC-SOUTHLAWN LN ROCKVILLE, MD20850 | — | — | 4.5 mi |
WABTEC RAILWAY ELECTRONICS GERMANTOWN, MD20876 | — | — | 5.4 mi |
GRIFFITH ENERGY SERVICES - DAMASCUS FUELS PLANT DAMASCUS, MD20872 | — | — | 9.8 mi |
NATIONAL INSTITUTE OF STANDARDS & TECHNOLOGY GAITHERSBURG, MD20899 | — | — | 1.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Montgomery County has experienced 8 federally declared disasters since 1971. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Gaithersburg compares by contaminant
Explore where Gaithersburg ranks among all Maryland cities for specific contaminants.
Water source & infrastructure
Where Gaithersburg's water comes from
Gaithersburg's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 805 people through 7 water systems.
Water bodies near Gaithersburg
Gaithersburg is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Gaithersburg
| System Name | PWSID | Population | Source |
|---|---|---|---|
| DOGWOOD MANOR MOBILE HOME PARK | MI0040008 | 190 | GW |
| HIDDEN VALLEY | MI0040208 | 125 | GW |
| CIRCLE DRIVE MOBILE HOME PARK | MI0040339 | 125 | GW |
| HUNTERS CREEK ESTATES | MI0040342 | 125 | GW |
| BEAN CREEK RESORT | MI0040554 | 112 | GW |
| PHELPS MOBILE HOME VILLA | MI0040494 | 98 | GW |
| ROUND LAKE ESTATES | MI0040307 | 30 | GW |
How Gaithersburg compares
Full Maryland rankings →Gaithersburg's score of 60.8/100 is on par with the average of 60/100 among major Maryland cities. It outscores 6 of 10 nearby cities.
Nearby cities
View Maryland rankings →About Gaithersburg, MD
Wikipedia →Gaithersburg is a city in Montgomery County, Maryland, United States. At the time of the 2020 United States census, Gaithersburg had a population of 69,657, making it the third-largest incorporated city and the ninth-most populous community in the state. Gaithersburg is located to the northwest of Washington, D.C., and is considered a suburb and a primary city within the Washington metropolitan area. Gaithersburg was incorporated as a town in 1878 and as a city in 1968.
Learn more about your water
Guides and resources related to Gaithersburg's water quality findings.
Explore water quality across Allegan
Frequently asked questions
Is Gaithersburg, MD tap water safe to drink?
Gaithersburg's water quality earned a grade of C (60.8/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #89 out of 107 cities tested in Maryland.
What contaminants are in Gaithersburg's water?
Lead was measured at 0.0 ppb (90th percentile). 66 violations are on record.
How is Gaithersburg's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Gaithersburg?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Gaithersburg's water come from?
Gaithersburg's water is sourced from Groundwater. The city has 7 water systems serving approximately 805 residents.
What health violations has Gaithersburg's water system had?
Gaithersburg has 29 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 25 violations remain unresolved.
Is Gaithersburg's groundwater at risk of contamination?
Gaithersburg uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 66 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Gaithersburg's water compare to other cities?
Gaithersburg ranks #89 out of 107 cities in Maryland (better than 17% of state cities) and #12054 out of 15744 cities nationally (23th percentile). The grade of C reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.