County · Maryland

St. Mary's County, Maryland: drinking water records

Name: Drinking water records for St. Mary's County, Maryland
Creator: U.S. Environmental Protection Agency
License: https://www.usa.gov/government-works

Explore EPA records for 38 community water systems across 26 ZIP codes in St. Mary's County, then find water-testing resources and available recent monitoring-station readings.

In focus38Community water systems

Public records. Clearer context.

Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages

Drinking-water records

EPA survey and compliance records are historical reports. UCMR 5 results are available for 4 of the 38 listed systems in this snapshot. A system with no reported PFAS detection is not a test of every tap or every contaminant.

systems in EPA's PFAS survey

systems where PFAS was found

systems at or above the PFOA or PFOS limit, on the yearly-average basis EPA uses

systems that have reached the lead action level

systems with a health-based violation since 2016

System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.

Water systems in this county

All 38 active community systems in the available county records, sorted by record completeness. Scroll the table to explore more systems.

Water system	People served	PFAS survey results	Health-based violations	Lead, 9 in 10 homes at or below
Charlotte Hall VA Home MD0180217	270	60	1	4.5 ppbbelow the action level
Lexington Park MD0180007	43,030	120	0	0 ppbbelow the action level
Patuxent Naval Air Station (Navfac-Wash) MD0180022	22,000	780	0	0 ppbbelow the action level
Saint Marys College MD0180013	2,200	0	1	0 ppbbelow the action level
Lord Calvert Trailer Park MD0180213	892	0	1	0 ppbbelow the action level
Piney Point MD0180034	672	60	0	0 ppbbelow the action level
Langley Mobile Home Park MD0180212	175	0	1	5 ppbbelow the action level
Mount Pleasant Water Co., INC. MD0180009	150	0	2	0 ppbbelow the action level
Christmas Tree Farm Trailer Park MD0180206	100	0	3	0 ppbbelow the action level
Town of Leonardtown MD0180006	5,000	0	0	0 ppbbelow the action level
Country Lakes MD0180023	3,016	0	0	0 ppbbelow the action level
Cedar Cove MD0180002	2,728	0	0	0 ppbbelow the action level
Wicomico Shores MD0180018	1,262	0	0	0 ppbbelow the action level
Greenbrier MD0180045	1,161	0	0	0 ppbbelow the action level
Breton Bay MD0180001	1,012	0	0	0 ppbbelow the action level
Hunting Quarters MD0180038	715	0	0	0 ppbbelow the action level
Rolling Acres MD0180017	699	0	0	0 ppbbelow the action level
St. Clements Shores MD0180012	620	0	0	0 ppbbelow the action level
Charlotte Hall MD1180005	615	0	0	0 ppbbelow the action level
Forrest Farm Subdivision MD0180054	577	0	0	0 ppbbelow the action level
Laurel Ridge MD0180037	560	0	0	0 ppbbelow the action level
Persimmon Hills MD0180046	514	0	0	0 ppbbelow the action level
Wilderness Run MD0180036	511	0	0	0 ppbbelow the action level
Lexington Estates MD0180207	300	0	0	0 ppbbelow the action level
Birch Manor MD0180015	272	0	0	0 ppbbelow the action level
Grandview Haven MD0180059	269	0	0	0 ppbbelow the action level
Piney Point Landings MD0180047	239	0	0	0 ppbbelow the action level
Villages at Leonardtown MD0180052	239	0	0	0 ppbbelow the action level
Fenwick Manor MD0180020	234	0	0	0 ppbbelow the action level
Leonardtown Farm MD0180057	193	0	0	0 ppbbelow the action level
Southgate MD0180048	188	0	0	0 ppbbelow the action level
King & Kennedy MD0180008	169	0	0	0 ppbbelow the action level
Holland Forest MD0180051	139	0	0	0 ppbbelow the action level
Fox Meadow MD0180041	128	0	0	0 ppbbelow the action level
Cook'S Trailer Court (Aka Garrett Tp) MD0180210	120	0	0	0 ppbbelow the action level
Hearts Desire MD0180044	65	0	0	0 ppbbelow the action level
Mulberry South MD0180042	65	0	0	0 ppbbelow the action level
Wild Goose Crest Subdivision MD0180056	65	0	0	0 ppbbelow the action level

USGS · Monitoring stations

The water, more recently.

Available station readings in St. Mary's County, Maryland. Each measurement keeps its time, unit and original source.

These readings describe water at a monitoring station. They do not test your tap, measure PFAS or lead, or determine whether water is safe to drink or swim in.

Recent observations load when this section comes into view.

How these readings update

We check for updates every 10 minutes while this section is visible and show supported observations from the last 48 hours. The time beside a reading is when USGS measured it; the checked time is when our service retrieved the response. We mark a reading more than 6 hours old as older. Provisional observations can change after USGS review. A missing reading does not mean zero or clean water.

Temperature, pH, dissolved oxygen, turbidity, conductivity, streamflow and water level are shown only where a station reports them. Different measurements have different units and sampling intervals. USGS data and documentation.

Your next step

Water testing, reports & local help.

Use these official directories to find your drinking-water agency, a certified laboratory and public water records. We have not yet added an individually reviewed local resource list for this county.

Official national directories

Water testing

Find your state’s private-well program

EPA’s state directory points well owners to local program information. Services and eligibility vary by state and county.

U.S. Environmental Protection Agency
Source reviewed 2026-09-15 · Source updated 2026-08-05

Water testing

Find a certified drinking-water laboratory

Use EPA’s directory to reach your state’s laboratory certification program. EPA does not provide on-request testing of residential drinking water.

U.S. Environmental Protection Agency
Source reviewed 2026-09-15 · Source updated 2026-08-11

Public records

Find your utility’s Consumer Confidence Report

EPA links to community water-system reports and explains how to read them. Look for your actual supplier rather than assuming every address in a county shares one system.

U.S. Environmental Protection Agency
Source reviewed 2026-09-15 · Source updated 2026-09-09

Public records

Explore USGS water observations

Find current and historical observations from USGS monitoring locations, including available stream, lake, and groundwater data. Measurements vary by station and do not replace a test of your household water.

U.S. Geological Survey
Source reviewed 2026-09-15

A county overview cannot identify every property’s water provider. If you use a public water system, confirm its name on your bill and request its annual Consumer Confidence Report. Private wells need their own testing; public-system records do not describe a private well.

Understand water testing and laboratory reports

Resource descriptions are compiled by Tap Water Lookup. Review dates describe our source check, not a new water sample. How we review sources · Suggest a correction

Explore your area

Local coverage in St. Mary's County

26ZIP areas in this overview

Explore the water-system records, recent station readings and testing resources on this county page. They describe the systems and stations identified in each section; they are not a separate water test for every community.

Towns and communities

California
Callaway
Leonardtown
Lexington Park
Mechanicsville
Piney Point
Tall Timbers

Explore water-system records Find water-testing resources

View ZIP areas and understand coverage

20606
20609
20618
20619California
20620Callaway
20621
20624
20626
20628
20630
20634California
20636
20650Leonardtown
20653Lexington Park
20656
20659Mechanicsville
20660
20667
20670
20674Piney Point
20680
20684
20686
20687
20690Tall Timbers
20692Tall Timbers

These Census ZIP Code Tabulation Areas are grouped here by their largest county overlap. A ZIP area can cross county lines and contain several water suppliers or private wells. Place labels reflect Census geography, not verified postal city names or utility service boundaries.

Records for these areas are currently presented in this county overview rather than individual ZIP reports. An unpublished report does not mean there are no water records. Confirm your supplier on your water bill; if you use a private well, testing your own well is the relevant next step.

Beyond this county page

Keep reading. Compare nearby.

PFASReading PFAS survey resultsWhat a detection, a reporting level and a yearly average mean in EPA’s PFAS survey records.LeadChoosing a lead filter1 system here has reached the lead action level. See how to check a filter’s lead-reduction certification.Your utilityFind your annual water reportConfirm the supplier on your bill, then read its Consumer Confidence Report for local results.

Counties near St. Mary's County

All Maryland counties

Sources and scope

EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Database prepared 2026-09-03.

Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.

Compiled by Tap Water Lookup from the sources identified on this page. Read the methodology and review process.