Certified labs by state
Maryland
Maryland routes private-well residents mainly to the Maryland Department of the Environment (MDE), local health departments, and University of Maryland Extension. Current official Maryland pages say private well owners are responsible for testing and maintenance, and MDE maintains the state drinking-water laboratory certification program and certified-lab list.
Checked against official sources on October 4, 2026. Rules and links change; confirm with the office listed before you act.
- Certifies drinking water labs
- Maryland Department of the Environment, Laboratory Certification Program
- Official certified lab list
- Official page →
- Free or low-cost testing
- MDE's PFAS private-well factsheet says the state generally does not fund or provide testing for private well owners; residents should contact their local health department about possible testing assistance.
Official resources in Maryland
Official MDE page explaining Maryland's drinking-water laboratory certification program and linking to the certified lab lists.
Current MDE PDF list of certified drinking-water laboratories, with approved tests for each lab.
State private-well landing page with Maryland well recommendations and links on arsenic and radium.
Maryland homeowner guidance on private wells, annual sampling, and when to test more often.
Land-grant guidance on which contaminants Maryland well owners should test for and how often.
Key facts for Maryland
- MDE's Laboratory Certification Program is Maryland's certifier for all certified drinking-water laboratories. https://mde.maryland.gov/programs/water/water_supply/pages/wsp-labcert.aspx
- MDE's certified drinking-water laboratory list PDF shows latest revisions dated October 1, 2026. https://mde.maryland.gov/programs/water/water_supply/Documents/Maryland-Certified-DW-Labs.pdf
- MDE says about 350,000 Maryland households rely on private wells. https://mde.maryland.gov/programs/Water/Water_Supply/Pages/Be_Well_Wise.aspx
- UMD Extension recommends annual testing for total coliform bacteria, E. coli, and nitrate. https://www.extension.umd.edu/resource/water-testing
- UMD Extension recommends pH, sulfate, and total dissolved solids every 3 years. https://www.extension.umd.edu/resource/water-testing
- MDE says arsenic above standards has occurred in some Coastal Plain wells, especially Piney Point and Aquia aquifers. https://mde.maryland.gov/programs/water/water_supply/documents/www.mde.state.md.us/assets/document/factsheets/arsenic_treatment_in_wells.pdf
What to do next
- Start with MDE's certified-lab list and choose a lab approved for the exact analytes you need, not just basic bacteria testing.
- Use UMD Extension's baseline schedule, then ask your county health department about local concerns such as arsenic, radon, or radium before ordering tests.
- Retest anytime water taste, odor, or appearance changes, after well repairs, or after a nearby chemical or fuel spill.
Helpful guides
- How to choose a state-certified drinking water lab
- What to test your private well water for (and how often)
- How to collect a well water sample without ruining the test
- How to read a water test report: MCLs, units and flags