Out of 166 ZIP codes with data in Maryland, these are the highest-ranked areas for lead (ppb). See also: National Worst ZIP Codes for Lead in Water | All Maryland Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 166 |
| Highest value | 10.4 ppb |
| Median value | 2.7 ppb |
| State | Maryland |
Top 100 Worst ZIP Codes
| Rank | ZIP Code | City | State | Lead (ppb) | Safety Score |
|---|---|---|---|---|---|
| 1 | 21654 | Oxford | MD | 10.4 ppb | — |
| 2 | 21673 | Trappe | MD | 10.4 ppb | — |
| 3 | 21643 | Hurlock | MD | 6.7 ppb | — |
| 4 | 21659 | Rhodesdale | MD | 6.7 ppb | — |
| 5 | 21401 | Annapolis | MD | 6.3 ppb | 82/100 |
| 6 | 21403 | Annapolis | MD | 6.3 ppb | 82/100 |
| 7 | 21048 | Finksburg | MD | 5.9 ppb | — |
| 8 | 21822 | Eden | MD | 5.8 ppb | — |
| 9 | 21826 | Fruitland | MD | 5.8 ppb | — |
| 10 | 20837 | Poolesville | MD | 5.0 ppb | 50/100 |
| 11 | 20842 | Dickerson | MD | 5.0 ppb | — |
| 12 | 21617 | Centreville | MD | 5.0 ppb | — |
| 13 | 21623 | Church Hill | MD | 5.0 ppb | — |
| 14 | 21640 | Henderson | MD | 5.0 ppb | — |
| 15 | 21657 | Queen Anne | MD | 5.0 ppb | — |
| 16 | 21811 | Berlin | MD | 4.6 ppb | — |
| 17 | 21613 | Cambridge | MD | 4.1 ppb | 100/100 |
| 18 | 21778 | Rocky Ridge | MD | 4.0 ppb | — |
| 19 | 21788 | Thurmont | MD | 4.0 ppb | 48/100 |
| 20 | 21719 | Cascade | MD | 3.9 ppb | — |
| 21 | 21780 | Sabillasville | MD | 3.9 ppb | — |
| 22 | 21849 | Parsonsburg | MD | 3.7 ppb | — |
| 23 | 21850 | Pittsville | MD | 3.7 ppb | — |
| 24 | 21874 | Willards | MD | 3.7 ppb | — |
| 25 | 21661 | Rock Hall | MD | 3.5 ppb | — |
| 26 | 21520 | Accident | MD | 3.3 ppb | — |
| 27 | 21541 | Mc Henry | MD | 3.3 ppb | — |
| 28 | 21550 | Oakland | MD | 3.3 ppb | — |
| 29 | 21813 | Bishopville | MD | 3.3 ppb | — |
| 30 | 21713 | Boonsboro | MD | 3.3 ppb | 50/100 |
| 31 | 21756 | Keedysville | MD | 3.3 ppb | 50/100 |
| 32 | 21779 | Rohrersville | MD | 3.3 ppb | — |
| 33 | 21853 | Princess Anne | MD | 3.1 ppb | — |
| 34 | 20639 | Huntingtown | MD | 3.0 ppb | — |
| 35 | 20701 | Annapolis Junction | MD | 3.0 ppb | — |
| 36 | 20723 | Laurel | MD | 3.0 ppb | 66/100 |
| 37 | 20759 | Fulton | MD | 3.0 ppb | — |
| 38 | 20763 | Savage | MD | 3.0 ppb | — |
| 39 | 20794 | Jessup | MD | 3.0 ppb | 63/100 |
| 40 | 21029 | Clarksville | MD | 3.0 ppb | — |
| 41 | 21042 | Ellicott City | MD | 3.0 ppb | 48/100 |
| 42 | 21043 | Ellicott City | MD | 3.0 ppb | 63/100 |
| 43 | 21044 | Columbia | MD | 3.0 ppb | — |
| 44 | 21045 | Columbia | MD | 3.0 ppb | 66/100 |
| 45 | 21046 | Columbia | MD | 3.0 ppb | 66/100 |
| 46 | 21074 | Hampstead | MD | 3.0 ppb | 50/100 |
| 47 | 21075 | Elkridge | MD | 3.0 ppb | — |
| 48 | 21076 | Hanover | MD | 3.0 ppb | 80/100 |
| 49 | 21102 | Manchester | MD | 3.0 ppb | 50/100 |
| 50 | 21104 | Marriottsville | MD | 3.0 ppb | 66/100 |
| 51 | 21155 | Upperco | MD | 3.0 ppb | — |
| 52 | 21163 | Woodstock | MD | 3.0 ppb | 63/100 |
| 53 | 21701 | Frederick | MD | 3.0 ppb | 66/100 |
| 54 | 21703 | Frederick | MD | 3.0 ppb | 49/100 |
| 55 | 21704 | Frederick | MD | 3.0 ppb | 66/100 |
| 56 | 21710 | Adamstown | MD | 3.0 ppb | 66/100 |
| 57 | 21754 | Ijamsville | MD | 3.0 ppb | 66/100 |
| 58 | 21770 | Monrovia | MD | 3.0 ppb | 66/100 |
| 59 | 21774 | New Market | MD | 3.0 ppb | 66/100 |
| 60 | 21777 | Point Of Rocks | MD | 3.0 ppb | 66/100 |
| 61 | 21794 | West Friendship | MD | 3.0 ppb | — |
| 62 | 21842 | Ocean City | MD | 2.8 ppb | — |
| 63 | 21030 | Cockeysville | MD | 2.7 ppb | 64/100 |
| 64 | 21052 | Fort Howard | MD | 2.7 ppb | 64/100 |
| 65 | 21057 | Glen Arm | MD | 2.7 ppb | — |
| 66 | 21071 | Glyndon | MD | 2.7 ppb | 64/100 |
| 67 | 21087 | Kingsville | MD | 2.7 ppb | 63/100 |
| 68 | 21093 | Lutherville Timonium | MD | 2.7 ppb | — |
| 69 | 21111 | Monkton | MD | 2.7 ppb | — |
| 70 | 21117 | Owings Mills | MD | 2.7 ppb | 64/100 |
| 71 | 21128 | Perry Hall | MD | 2.7 ppb | 64/100 |
| 72 | 21131 | Phoenix | MD | 2.7 ppb | 64/100 |
| 73 | 21133 | Randallstown | MD | 2.7 ppb | 64/100 |
| 74 | 21136 | Reisterstown | MD | 2.7 ppb | 64/100 |
| 75 | 21152 | Sparks Glencoe | MD | 2.7 ppb | — |
| 76 | 21153 | Stevenson | MD | 2.7 ppb | — |
| 77 | 21162 | White Marsh | MD | 2.7 ppb | 64/100 |
| 78 | 21201 | Baltimore | MD | 2.7 ppb | 64/100 |
| 79 | 21202 | Baltimore | MD | 2.7 ppb | 64/100 |
| 80 | 21204 | Towson | MD | 2.7 ppb | 64/100 |
| 81 | 21205 | Baltimore | MD | 2.7 ppb | 64/100 |
| 82 | 21206 | Baltimore | MD | 2.7 ppb | 64/100 |
| 83 | 21207 | Gwynn Oak | MD | 2.7 ppb | 64/100 |
| 84 | 21208 | Pikesville | MD | 2.7 ppb | 64/100 |
| 85 | 21209 | Baltimore | MD | 2.7 ppb | 64/100 |
| 86 | 21210 | Baltimore | MD | 2.7 ppb | 62/100 |
| 87 | 21211 | Baltimore | MD | 2.7 ppb | 62/100 |
| 88 | 21212 | Baltimore | MD | 2.7 ppb | 64/100 |
| 89 | 21213 | Baltimore | MD | 2.7 ppb | 64/100 |
| 90 | 21214 | Baltimore | MD | 2.7 ppb | 64/100 |
| 91 | 21215 | Baltimore | MD | 2.7 ppb | 64/100 |
| 92 | 21216 | Baltimore | MD | 2.7 ppb | 64/100 |
| 93 | 21217 | Baltimore | MD | 2.7 ppb | 64/100 |
| 94 | 21218 | Baltimore | MD | 2.7 ppb | 64/100 |
| 95 | 21219 | Sparrows Point | MD | 2.7 ppb | 64/100 |
| 96 | 21220 | Middle River | MD | 2.7 ppb | 64/100 |
| 97 | 21221 | Essex | MD | 2.7 ppb | 64/100 |
Methodology
Lead rankings are based on the 90th percentile lead testing value (PB90) reported by water systems under the Lead and Copper Rule. When CCR data is unavailable, EPA SDWIS lead sampling data is used. The EPA action level for lead is 15 ppb (0.015 mg/L). There is no safe level of lead exposure.
Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-10-14.
Frequently Asked Questions
What is a dangerous lead level in water?
The EPA action level is 15 parts per billion (ppb). The American Academy of Pediatrics recommends no more than 1 ppb for school drinking water. There is no safe level of lead exposure for children.
How is lead measured in water?
Water systems collect samples from homes with known lead service lines or lead solder. The 90th percentile value (PB90) means 90% of samples tested below that level. If PB90 exceeds 15 ppb, the system must take corrective action.
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