Montgomery County, Maryland has about 1,082,273 residents (Census 2024 estimate) and 6 community water systems in EPA records. The largest local system is Washington Suburban Sanitary Commission, serving about 1,900,000 people from surface water.
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
Washington Suburban Sanitary Commission Measured (utility report, 2025) · High confidence
58–213 mg/L (varies by area; no single average published)
Source: WASHINGTON SUBURBAN SANITARY COMMISSION water quality report, 2025
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
For a 3-person home using 57 gallons per person per day and regenerating weekly, you'd remove about 10,773 grains between regenerations. Suggested size: 24,000 grain. Hardness varies by area here, so this uses the harder plant's figure (9 gpg). If your address gets softer water, a smaller unit may do; check your area in the utility report or test your tap.
Estimate only. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
The 6 biggest of 6 community water systems on EPA records for this county. Service areas don't follow county lines; your water bill names your provider.
MD0150005 · serves about 1,900,000 people · Surface water
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2018-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
MD0150003 · serves about 52,000 people · Surface water
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2018-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
MD0150002 · serves about 6,005 people · Surface water
Lead 90th percentile: 5 ppb (period starting 2016-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
MD0150102 · serves about 1,248 people · Surface water
No lead result in this dataset.
MD0150101 · serves about 256 people · Surface water
No lead result in this dataset.
MD0150103 · serves about 97 people · Surface water
No lead result in this dataset.
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
A PFAS detection is not a violation. Federal limits (4 ppt for PFOA and PFOS) apply to running annual averages, with compliance required by 2029. In May 2026 EPA proposed extending the PFOA/PFOS deadline to 2031 and removing other PFAS limits; not final as of 2026-10-21.
These are public records for whole systems. Your home's pipes, fixtures and any private well can change what you drink. A certified lab test or a hardness test strip gives you your own numbers. Then use our PFAS and lead filter selector to see which certifications to look for.
None of the 6 largest systems here have a health-based violation in EPA records since October 2021. Washington Suburban Sanitary Commission's most recent lead 90th percentile was below the lab detection limit (2018), below the 15 ppb action level. Public records can't guarantee what comes out of your tap, especially with older plumbing, so a home test is the surest check.
Washington Suburban Sanitary Commission reports hardness from 58 to 213 mg/L depending on where you live, with no single system-wide average, so check your area in its report or test your water. For a 3-person home at 9 gpg (the harder plant's figure, since your address may get either), our softener calculator suggests a 24,000 grain unit as a starting point.
3 of the 3 sampled systems listed here detected at least one PFAS in EPA's UCMR 5 testing, and 2 results were above the level of a federal limit in at least one sample. A detection isn't a violation: federal PFAS limits apply to running annual averages starting in 2029.
Most homes are served by Washington Suburban Sanitary Commission or one of the other systems listed on this page, but service areas don't follow county lines. Your water bill names your provider, and its annual Consumer Confidence Report has the full test results.
Data as of October 21, 2026. Figures are copied from public records and combined with our own calculations; they can be out of date or wrong. Tapped Out isn't affiliated with any utility or the EPA. Written and reviewed by the Tapped Out team. How we calculate · All sources.