41 named for arsenic itself on the list.
Per the state list or a state web page. Call to confirm.
Located outside Maryland but on its list.
USGS estimate for Maryland.
How many labs test for arsenic in Maryland
41 labs on Maryland's official drinking-water lab list are certified to test for arsenic. All 41 are named for arsenic on the list. The Maryland list does not say which labs take samples from homeowners, so call a lab before you send one. 29 are located outside Maryland.
The list is published by the Maryland Department of the Environment (MDE) - Water Supply Program, Laboratory Certification Program. List versions on file: Latest Revisions: 10/1/2026; Latest Revisions: 10/1/2026; PFAS list Last Rev 101/2026. Fetched 2026-11-07 (UTC).
Maryland labs certified for arsenic
| Lab | Location | Arsenic certification | Public samples | Cert. expiry |
|---|---|---|---|---|
| ALLIANCE TECHNICAL GROUP - AKRON | Cuyahoga Falls, OH | Named on the official list | Public samples: ask the lab | Not on the list |
| ALLIANCE TECHNICAL GROUP - NEWARK | Mountainside, NJ | Named on the official list | Public samples: ask the lab | Not on the list |
| ALS ENVIRONMENTAL - MIDDLETOWN | Middletown, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| AMERICAN WATER LABORATORY - BELLEVILLE | Belleville, IL | Named on the official list | Public samples: ask the lab | Not on the list |
| CALIBER ANALYTICAL SERVICES, LLC | Towson, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| CHESAPEAKE ENVIRONMENTAL LABORATORY, INC | Stevensville, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| EMSL ANALYTICAL, INC - CINNAMINSON | Cinnaminson, NJ | Named on the official list | Public samples: ask the lab | Not on the list |
| ENVIRONMENTAL HAZARDS SERVICES, LLC | North Chesterfield, VA | Named on the official list | Public samples: ask the lab | Not on the list |
| EUROFINS LANCASTER LABORATORIES ENVIRONMENT TESTING, LLC | Lancaster, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| EUROFINS POMONA (formerly Eurofins Eaton Analytical-Monrovia) | Pomona, CA | Named on the official list | Public samples: ask the lab | Not on the list |
| EUROFINS SOUTH BEND (formerly Eurofins Eaton Analytical, LLC-South Bend) | South Bend, IN | Named on the official list | Public samples: ask the lab | Not on the list |
| FREDERICKTOWNE LABS, INC | Myersville, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| GEL LABORATORIES, LLC | Charleston, SC | Named on the official list | Public samples: ask the lab | Not on the list |
| GEOCHEMICAL TESTING | Somerset, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| HOME LAND LABS - TOWSON | Towson, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| KATAHDIN ANALYTICAL SERVICES, LLC | Scarborough, ME | Named on the official list | Public samples: ask the lab | Not on the list |
| LABORATORY ANALYTICAL AND BIOLOGICAL SERVICES, INC (LABS INC) | New Oxford, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| M. J. REIDER ASSOCIATES, INC | Reading, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| MARYLAND SPECTRAL SERVICES, INC | Baltimore, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| MICROBAC LABORATORIES, INC - BALTIMORE | Baltimore, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| MICROBAC LABORATORIES, INC - DAYVILLE | Dayville, CT | Named on the official list | Public samples: ask the lab | Not on the list |
| NAN TECHNOLOGIES, INC | Halethorpe, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| NATIONAL TESTING LABORATORIES, LTD | Ypsilanti, MI | Named on the official list | Public samples: ask the lab | Not on the list |
| NSF INTERNATIONAL | Ann Arbor, MI | Named on the official list | Public samples: ask the lab | Not on the list |
| ONTERRIS LABORATORIES, LLC- Richmond (formerly ENTHALPY ANALYTICAL, LLC- Richmond) | Richmond, VA | Named on the official list | Public samples: ask the lab | Not on the list |
| PACE ANALYTICAL - MOUNT JULIET - National Center for Testing & Innovation | Mount Juliet, TN | Named on the official list | Public samples: ask the lab | Not on the list |
| PACE ANALYTICAL SERVICES, LLC - ALTOONA | Altoona, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| PACE ANALYTICAL SERVICES, LLC - MANSFIELD | Mansfield, MA | Named on the official list | Public samples: ask the lab | Not on the list |
| PACE ANALYTICAL SERVICES, LLC - MELVILLE | Melville, NY | Named on the official list | Public samples: ask the lab | Not on the list |
| PACE ANALYTICAL SERVICES, LLC - MINNEAPOLIS | Minneapolis, MN | Named on the official list | Public samples: ask the lab | Not on the list |
| PACE ANALYTICAL SERVICES, LLC - ORMOND BEACH | Ormond Beach, FL | Named on the official list | Public samples: ask the lab | Not on the list |
| PHASE SEPARATION SCIENCE, INC | Baltimore, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| PURE-TEST LABORATORY | Myerstown, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| SCHNEIDER LABORATORIES GLOBAL, INC | Richmond, VA | Named on the official list | Public samples: ask the lab | Not on the list |
| SGS NORTH AMERICA INC - DAYTON | Dayton, NJ | Named on the official list | Public samples: ask the lab | Not on the list |
| SPL-READING | Reading, PA | Named on the official list | Public samples: ask the lab | Not on the list |
| WATER TESTING LABS OF MD - STEVENSVILLE | Stevensville, MD | Named on the official list | Public samples: ask the lab | Not on the list |
| BALTIMORE COUNTY BUREAU OF UTILITIES ENGINEERING & REGULATION LAB | Baltimore, MD | Named on the official list | Public samples: ask the lab Looks like a utility or municipal lab, judging by the name (our label, not the state list) | Not on the list |
| EUROFINS DRINKING WATER AND WASTEWATER CENTRAL, LLC (formerly Alloway) | Marion, OH | Named on the official list | Public samples: ask the lab Looks like a utility or municipal lab, judging by the name (our label, not the state list) | Not on the list |
| FREDERICK COUNTY DIVISION OF WATER & SEWER UTILITIES LABORATORY | Frederick, MD | Named on the official list | Public samples: ask the lab Looks like a utility or municipal lab, judging by the name (our label, not the state list) | Not on the list |
| WASHINGTON SUBURBAN SANITARY COMMISSION LABORATORY DIVISION (WSSC) | Silver Spring, MD | Named on the official list | Public samples: ask the lab Looks like a utility or municipal lab, judging by the name (our label, not the state list) | Not on the list |
How the Maryland list marks public samples (whole list). Not stated per lab. MDE's Be Well Wise page tells private well owners to "Have your water tested periodically by a state-certified laboratory that conducts a drinking water test", but neither that page nor MDE's list says which labs take samples from private well owners.
Before you send a sample, call the lab to confirm it is currently certified for the exact test and method, that it accepts samples from homeowners, and how to collect and ship them. Status can change between list updates.
Why test for arsenic in Maryland
Arsenic is invisible, tasteless and mostly natural, and it comes in two forms that respond very differently to treatment. Read our arsenic explainer.
USGS estimates that the most private-well users with arsenic above 10 µg/L, EPA's limit for public water, live in Wicomico County, Baltimore County and Harford County (about 6,673 people in Wicomico County, 2010 base year). USGS describes this kind of estimate as useful "for broad screening of the population at risk", so it says nothing certain about any one well. [1]
Show the numbers
| Item | Value | Note |
|---|---|---|
| Wicomico County | 6,673 people (2010 base year) | |
| Baltimore County | 4,039 people (2010 base year) | |
| Harford County | 3,505 people (2010 base year) | |
| Calvert County | 3,020 people (2010 base year) | |
| Anne Arundel County | 2,558 people (2010 base year) | |
| St. Mary's County | 2,348 people (2010 base year) |
USGS model estimate for broad screening, not a measurement of any well. Only a test tells you about your own well. Source: USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017), accessed 2026-11-01.
About 1,423,948 people in Maryland used private wells in 2015, by the USGS estimate of people on domestic self-supplied water. [2] Federal limits are written for public water systems, not private wells, so testing is up to the owner.
For tests that depend on your home (farms nearby, old plumbing, a new baby), use the which-tests checklist. When results arrive, check your numbers against EPA's limits. State guidance, county data and every lab: Maryland.
Other tests in Maryland
- USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017)
- USGS, Estimated use of water in the United States, county-level data for 2015 (Dieter et al., ver. 2.0, 2018)
- Maryland's Certified Drinking Water Laboratories (MDE Laboratory Certification Program) (official list)
Maryland's Certified Drinking Water Laboratories (MDE Laboratory Certification Program).
Official source