About this list
- Agency
- Maryland Department of the Environment (MDE) - Water Supply Program, Laboratory Certification Program
- Format
- PDF list (7 pp): MD certification number and approved test groups per lab (codes keyed to MDE's 'List of Approved Contaminants'), plus MDE's PFAS list (EPA 533 / 537.1 per lab); no expiry dates
- Homeowner flag
- 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.
Certified as ofLatest Revisions: 10/1/2026
Maryland's Certified Drinking Water Laboratories (MDE Laboratory Certification Program). Fetched 2026-11-07 (UTC).
Official sourceTesting your well in Maryland
How often to test
- Maryland's Department of the Environment (MDE) says that at a minimum a well should be sampled every year, for total coliform bacteria, nitrates, total dissolved solids and pH. It also advises sampling any time you notice a change in odor, taste or appearance or suspect other contaminants. More frequent testing may be warranted, for example with unexplained illnesses in the family, a household member who is pregnant or nursing, or a contaminant found in a neighbor's water. [1]
- University of Maryland Extension recommends a comprehensive test if you have not tested in several years, then routine tests: coliform bacteria and nitrates every year, and pH, total dissolved solids and sulfates every 3 years. It also suggests checking with your local health department and county well permitting office about contaminants of local concern. [2]
Free testing
We found no statewide free testing program in Maryland. Ask your county health department whether it runs one.
Testing programs and help
- If you suspect other contaminants, MDE says local health departments, University of Maryland Extension, geologists at local universities and nearby public water systems can help to identify potential problems. [1]
Buying or selling a home
- Maryland law (Real Property § 10-713, added by Chapter 587 of 2023, effective October 1, 2024) says a contract to sell real property with a private or domestic water supply well must include a provision requiring, as a condition of the sale, that the buyer make sure the well water is tested. Settlement may not take place until the seller and the buyer have each received and reviewed the results, and both certify this in writing at settlement. Results stay valid for 3 years, and the buyer may waive the testing in writing. The test must be done by a State-approved water sampler and a State-approved laboratory and cover at least bacteria, nitrate and turbidity (Environment § 9-4A-01). [3]
- For private residential, real estate and other non-compliance testing, MDE's Laboratory Certification Program recommends using a certified sampler to ensure reliable test results. [4]
State lab and rules
- MDE advises having your water tested periodically by a state-certified laboratory that does drinking water tests. [1]
- MDE's Laboratory Certification Program is the accreditation body for all certified drinking water labs in Maryland. It publishes a list of certified drinking water labs with each lab's approved tests, and a separate list of labs approved for PFAS. [4]
Show the numbers
| Item | Value | Note |
|---|---|---|
| Zone 1 | 8 counties | |
| Zone 2 | 9 counties | |
| Zone 3 | 7 counties |
Radon in indoor air, not in water. EPA: Zone 1 = highest potential (average indoor radon may be above 4 pCi/L); Zone 2 = 2 to 4; Zone 3 = below 2. EPA says the map should not be used to decide whether an individual home needs testing. Source: U.S. EPA, Map of Radon Zones, county list (EPA 402/A-16/001, spreadsheet Sep 2025), accessed 2026-11-01.
Sources
- Maryland Department of the Environment, Water Supply Program, Be Well Wise
- University of Maryland Extension, Water Testing (updated Apr 29, 2021)
- Maryland Code, Real Property § 10-713, added by Chapter 587 of 2023 (HB 11, Private Well Safety Act of 2023), effective October 1, 2024 (read from the Internet Archive capture of October 17, 2026 of the enrolled chapter; the live legislature site did not connect)
- Maryland Department of the Environment, Laboratory Certification Program (page last revised May 13, 2026)
- U.S. EPA, Map of Radon Zones, county list (EPA 402/A-16/001, spreadsheet Sep 2025)
Loan test (FHA, VA, USDA) in Maryland
- VA. Test results are valid for 90 days from the date the local health authority certifies them, unless the local authority says otherwise. VA’s chapter names no list of contaminants: the water must meet the local health authority’s requirements, or EPA guidelines where it has none. Your lender may ask for specific tests.
- FHA. A well test is required in the situations FHA’s handbook lists, among others, and the report may not be more than 180 days old at disbursement.
- USDA. Guaranteed loans need a water quality test for a private well, done by the local health authority or a state-certified lab, and no more than 180 days old at closing.
Here:
- 1 lab on the Maryland list print a loan or home-sale package price on their own site: see the price table.
Lenders can ask for more (extra tests, a particular lab, who takes the sample): ask your lender before you book. Federal rules as read on Nov 3, 2026 source 1 source 2 source 3. Full comparison: VA, FHA and USDA well water test requirements. Loan test kits sold by mail, with price and days to results: kits compared.
What Maryland labs say on their own websites
State lists say what a lab is certified for, not whether it takes your sample or what it costs. We read each lab’s own site; a second reader re-checked every fact below. 13 labs on this list are on our register so far; 8 say they take homeowner samples and 1 print a price.
| Lab | Bacteria (coliform / E. coli) | Nitrate | Arsenic | Lead | Basic well panel | Home sale / loan package | Turnaround |
|---|---|---|---|---|---|---|---|
| WATER TESTING LABS OF MD - ANNAPOLIS Annapolis, MD · You collect it, or lab staff can | Coliform Bacteria $85.00 source Bacteria Only $150.00 source | – | Total Arsenic in drinking water $55.00 source | Lead in drinking water, 2 tests, first draw and flushed $75.00 source Lead + Copper in drinking water, 2 tests, first draw and flushed $100.00 source | Coliform Bacteria, Nitrates + Nitrites, Sand, Turbidity, pH $125.00 source Coliform Bacteria, Nitrates + Nitrites, Sand, Turbidity, pH, Iron $135.00 source | Conventional Financing $175.00 source FHA Financing $245.00 source | – |
Say they take homeowner samples: CERTIFIED WATER TESTING, LLC, CHESAPEAKE ENVIRONMENTAL LABORATORY, INC, FOUNTAIN VALLEY ANALYTICAL LABORATORY, INC, HOME LAND LABS - ANNAPOLIS, HOME LAND LABS - FOREST HILL, HOME LAND LABS - TOWSON, HOME LAND LABS - WALDORF, WATER TESTING LABS OF MD - ANNAPOLIS.
Prices exactly as each lab prints them, read 14 Nov 2026 to 15 Nov 2026; re-checked every 90 days. Labs not shown have not been read yet or print nothing for homeowners. Confirm price and turnaround with the lab.
Labs by contaminant
Labs on the Maryland list for one test, with homeowner-accepting labs first.
Well water by county
Private-well population (USGS, 2015), arsenic estimate, radon zone and nearby labs for each county with at least 1,000 people on private wells, largest first.
Prince George's County277,375 on wellsAnne Arundel County166,914 on wellsBaltimore County131,371 on wellsFrederick County107,440 on wellsMontgomery County74,900 on wellsCarroll County72,149 on wellsHoward County66,244 on wellsCecil County62,461 on wellsWicomico County58,504 on wellsCalvert County57,194 on wellsHarford County53,183 on wellsCharles County52,344 on wellsSt. Mary's County46,880 on wellsWashington County43,831 on wellsQueen Anne's County34,045 on wellsGarrett County20,216 on wellsCaroline County20,137 on wellsTalbot County19,803 on wellsWorcester County15,403 on wellsSomerset County13,883 on wellsDorchester County12,081 on wellsAllegany County9,598 on wellsKent County7,992 on wells