Maryland water quality
Maryland has 3,049 active public water systems (7,795 on file total), 451 of them graded by TapGraded.
Grade distribution
Biggest water systems
WASHINGTON SUBURBAN SANITARY COMMISSION
LAUREL, MD · 1,900,000 served
CITY OF BALTIMORE
BALTIMORE, MD · 1,600,000 served
GLEN BURNIE-BROADNECK
MILLERSVILLE, MD · 290,606 served
HOWARD COUNTY D.P.W. DISTRIBUTION
COLUMBIA, MD · 286,158 served
HARFORD COUNTY D.P.W.
ABINGDON, MD · 104,567 served
CITY OF HAGERSTOWN
HAGERSTOWN, MD · 92,200 served
NEW DESIGN - FREDERICK COUNTY
FREDERICK, MD · 74,911 served
CROFTON-ODENTON
MILLERSVILLE, MD · 62,986 served
FORT GEORGE G. MEADE
FORT MEADE, MD · 62,234 served
CITY OF FREDERICK
FREDERICK, MD · 54,000 served
Lowest-graded systems
Active, graded systems serving at least 10,000 people, ordered by lowest Tap Grade first.
TOWN OF ELKTON
ELKTON, MD · 15,625 served
CITY OF BALTIMORE
BALTIMORE, MD · 1,600,000 served
CITY OF WESTMINSTER
WESTMINSTER, MD · 35,256 served
CITY OF SALISBURY
SALISBURY, MD · 30,343 served
CITY OF ABERDEEN
ABERDEEN, MD · 18,006 served
MARYLAND AMERICAN WATER COMPANY
BEL AIR, MD · 13,200 served
TOWN OF OCEAN CITY
OCEAN CITY, MD · 30,000 served
CITY OF HAVRE DE GRACE
HAVRE DE GRACE, MD · 14,000 served
CITY OF BOWIE
BOWIE, MD · 25,000 served
LEXINGTON PARK
CALIFORNIA, MD · 43,030 served
Cities in Maryland
Source: EPA SDWIS/ECHO · Data as of 2026Q2