Well water test when selling a house in Maryland
1 statewide rule and 0 local rules from official sources.
General information, not legal advice. This is our summary of the official rule as we read it. The ordinance or code and the health department decide: confirm with them before you list, sign or close.
Statewide: well water test at sale
Any real property with a private or domestic water supply well. The buyer can waive the test in writing.
| Question | What the official text says |
|---|---|
| What is required | The sale contract must make a well-water test a condition of the sale, and the buyer must make sure it is done by a State-approved sampler and a State-certified laboratory (at least bacteria, nitrate and turbidity). Settlement waits until seller and buyer have both received and reviewed the results Source: web.archive.org via Wayback capture 2026-10-17 of the official enrolled chapter |
| Triggered by | sale Source: mgaleg.maryland.gov |
| Deadline | Settlement may not occur until the seller and the buyer have each received and reviewed the test results; both certify this in writing at settlement Source: mgaleg.maryland.gov |
| Who arranges it | The buyer must ensure the test is done (the sale contract must make it a condition of the sale) Source: mgaleg.maryland.gov |
| How long a report is valid | Results remain valid for 3 years Source: mgaleg.maryland.gov |
| Exemptions |
Source: mgaleg.maryland.gov |
| In force since | October 1, 2024 Source: mgaleg.maryland.gov |
Checked on November 9, 2026: read in a web-archive copy of the official page (the live site was blocked from our connection).
Private wells in Maryland
About 1,423,948 of Maryland’s 6,006,401 residents (24%) got their drinking water from a private well in 2015, by the USGS estimate.
Source: USGS county water use 2015 (Dieter et al., 2018); 24 counties in the USGS table.
Where private wells (and usually septic systems) are most common
Maryland ranks 12 of 45 states and territories by people on private wells (USGS 2015). In 8 of its 24 counties more than half of residents drink from a private well; homes there usually also treat wastewater on site, so a septic check and a well test tend to come up together at sale. The highest shares:
- Queen Anne's County: 70% of 48,904 residents on a private well
- Garrett County: 69% of 29,460 residents on a private well
- Calvert County: 63% of 90,595 residents on a private well
- Caroline County: 62% of 32,579 residents on a private well
- Cecil County: 61% of 102,382 residents on a private well
- Wicomico County: 57% of 102,370 residents on a private well
- Somerset County: 54% of 25,768 residents on a private well
- Talbot County: 53% of 37,512 residents on a private well
USGS county water use 2015 (Dieter et al., 2018). The USGS table counts well users, not septic systems; no national county count of septic systems exists.
Soils for septic drain fields in Maryland
Across the 23 counties with USDA soil survey data, 92% of rated land is “very limited” for a conventional septic drain field. Most limited: Calvert County (100%), Caroline County (100%), Dorchester County (100%). Least limited: Baltimore City (48%), Washington County (63%), Frederick County (76%).
Source: USDA NRCS Soil Survey Geographic Database (SSURGO), via Soil Data Access, rating “ENG - Septic Tank Absorption Fields”, read November 15, 2026. County-wide ratings, not a test of one lot.
How the neighbouring states compare
Maryland has a statewide rule. Of its 4 neighbouring states, 1 has a statewide rule at sale; a buyer moving across the line may meet a different rule. From our register of official rules:
- Delaware: statewide septic system rule at sale.
Testing a well? See certified well-water labs and testing advice in Maryland.
Other states: all states.