Maryland well water testing: what MDE recommends
About 350,000 Maryland households rely on private wells, and owners are responsible for the safety of their own drinking water, according to the Maryland Department of the Environment (MDE). [source]
What and when to test
- At minimum, sample annually for total coliform bacteria, nitrates, total dissolved solids and pH.
- Sample whenever odor, taste or appearance changes, or you suspect contaminants.
- More frequent testing may be warranted, for example with unexplained illness in the family, someone pregnant or nursing, or a neighbor finding a contaminant. [source]
Where to test
Use a state-certified laboratory that does drinking water testing. MDE publishes a list of certified labs. [source] [source] Local health departments, University of Maryland Extension, local university geologists and nearby public water systems can help identify likely problems. [source]
Contact: MDE Water Well Construction Program, 410-537-3784. [source]
FAQ
What should Maryland well owners test for each year?
MDE recommends annual sampling for total coliform bacteria, nitrates, total dissolved solids and pH.
Where can I find a certified lab in Maryland?
MDE publishes a list of water quality laboratories certified in Maryland.
Sources
- Maryland Dept. of the Environment – Be Well Wise (accessed 2026-10-21)
- MDE – Water Quality Laboratories Certified in Maryland (PDF) (accessed 2026-10-21)
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