Gaithersburg, MD Water Quality Report
Gaithersburg water quality (WSSC Water)
Gaithersburg is served by WSSC Water (Washington Suburban Sanitary Commission). Below: EPA violation history, UCMR5 PFAS monitoring, lead risk in older homes, and NSF-certified filters for Montgomery County tap water.
Serving 70K residents via Washington Suburban Sanitary Commission (WSSC Water)
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Gaithersburg water meets EPA legal standards, but legal compliance is not the same as being free of health concerns. The issues flagged below are worth understanding before deciding whether to filter. EPA limits are often set below what independent scientists recommend as safe thresholds.
Gaithersburg is served by WSSC Water, one of the largest utilities in the US (Montgomery & Prince George's counties).
WSSC draws primarily from the Potomac River and Patuxent River — surface water treated to federal standards.
PFAS has been monitored under EPA UCMR5; treat at the tap if you want extra protection beyond utility compliance.
Homes built before 1986 should test for lead from premise plumbing even when the utility meets EPA limits.
Source: EPA UCMR5 national monitoring dataset · Testing period 2023–2025 · MCL = Maximum Contaminant Level (legally enforceable limit) · Health limit = EPA health advisory threshold
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COMMON QUESTIONS
Is Gaithersburg tap water safe to drink in 2025?
Gaithersburg water meets EPA legal standards, but meeting legal standards is not the same as being free of health concerns. EPA limits are set based on treatment feasibility, not always on what independent scientists consider safe. The main concerns for Gaithersburg residents are disinfection byproducts and pfas monitoring. Enter your ZIP above to see the full violation history for your specific water system.
Does Gaithersburg water have PFAS?
EPA UCMR5 monitoring data for Gaithersburg (water system MD0150005) is shown above. PFAS — sometimes called "forever chemicals" — are synthetic compounds that don't break down in the body. Only reverse osmosis systems or NSF 58-certified carbon block filters reliably remove PFAS from tap water. Standard pitcher filters do not remove PFAS.
Does Gaithersburg water have lead?
Lead in tap water almost always comes from the pipes inside your home or building, not the treatment plant. Homes built before 1986 in Gaithersburg are most at risk because they may have lead solder, brass fittings, or lead service lines. The EPA has no safe level for lead in children. An NSF/ANSI 53-certified filter or reverse osmosis system removes lead at the tap.
What water filter is best for Gaithersburg?
For Gaithersburg's water profile — disinfection byproducts, pfas monitoring — a reverse osmosis system addresses the widest range of contaminants. Under-sink RO (Waterdrop G3P800, Aquasana SmartFlow) is the gold standard for homeowners. Renters can use a countertop RO like the Waterdrop K19-S Countertop RO — zero installation required. Clearly Filtered pitchers are the best non-RO option for PFAS and lead.
How do I get my Gaithersburg water tested?
For the most accurate results for your specific tap, use a certified mail-in lab test rather than relying on city-wide data. SimpleLab Tap Score tests for 100+ contaminants including PFAS, lead, arsenic, and nitrates. Results come with a detailed health assessment and filter recommendations. City-wide EPA data like what you see above is a strong baseline, but your home's plumbing can add contaminants after the water leaves the treatment plant.
As of October 2024, all US water utilities must publish a public inventory of their lead service lines — the pipes connecting the water main to your home. Even if your utility water tests clean at the treatment plant, lead can leach from these pipes into your tap. Homes built before 1986 are most at risk.
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City-wide data is just the start. Enter your ZIP to see your exact water system's EPA report, PFAS levels, and violation history — then get the right filter for your home.
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Data reviewed by Joe Letorney, 30-year water treatment specialist →