Frederick County, Maryland
35 ZIP codes · Avg score 53/100 · Grade D · Updated 2026-06-03
For households across Frederick County's 35 ZIP codes, below-average water safety data and recurring health violations make local monitoring worthwhile — checking the specific system serving an address is the most actionable starting point.
How Frederick County Compares
How Frederick County Compares
Frederick County scores 8 points below the Maryland state average (61/100) and 15 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Frederick County, Maryland
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12 (asthma 9.7%, diabetes 11%)
Estimated additional annual cost per homeowner: $1,925, driven primarily by sea_level
Infrastructure: 0.348% avg pipe failure probability, 27% of ZIPs at high risk
58.3% of homes built before 1978 (lead paint era)
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,925
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
118,480 housing units in Frederick County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Frederick County
Remediation costs are relatively manageable for most homeowners in Frederick County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Frederick County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Frederick County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | New Design - Frederick County | 74,911 | 25 |
| 2 | Fountaindale South | 2,610 | 20 |
| 3 | City of Frederick | 54,000 | 18 |
| 4 | Fort Detrick | 7,900 | 18 |
| 5 | Knolls of Windsor | 1,553 | 18 |
25 total water systems serve Frederick County.
All ZIP Codes in Frederick County
35 ZIP codes tracked in Frederick County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 21773 | Myersville | 70 | B | 0 | $476K |
| 2 | 21704 | Frederick | 69 | C | 3 (1 health) | $586K |
| 3 | 21716 | Brunswick | 69 | C | 2 | $335K |
| 4 | 21771 | Mount Airy | 69 | C | 7 (1 health) | $532K |
| 5 | 21705 | Frederick | 65 | C | 3 (1 health) | — |
| 6 | 21709 | Frederick | 65 | C | 3 (1 health) | — |
| 7 | 21788 | Thurmont | 65 | C | 0 | $343K |
| 8 | 21702 | Frederick | 64 | C | 3 (1 health) | $385K |
| 9 | 21703 | Frederick | 64 | C | 3 (1 health) | $364K |
| 10 | 21798 | Woodsboro | 64 | C | 6 | $466K |
| 11 | 21727 | Emmitsburg | 63 | C | 5 | $304K |
| 12 | 21015 | Bel Air | 62 | C | 1 | $418K |
| 13 | 21793 | Walkersville | 62 | C | 1 | $416K |
| 14 | 21769 | Middletown | 61 | C | 2 (1 health) | $491K |
| 15 | 21701 | Frederick | 59 | C | 3 (1 health) | $405K |
| 16 | 21710 | Adamstown | 53 | D | 0 | $582K |
| 17 | 21714 | Braddock Heights | 53 | D | 0 | $315K |
| 18 | 21717 | Buckeystown | 53 | D | 0 | $430K |
| 19 | 21754 | Ijamsville | 53 | D | 0 | $620K |
| 20 | 21755 | Jefferson | 53 | D | 0 | $494K |
| 21 | 21774 | New Market | 53 | D | 0 | $508K |
| 22 | 21757 | Keymar | 45 | D | 0 | $414K |
| 23 | 21758 | Knoxville | 45 | D | 0 | $388K |
| 24 | 21715 | Brownsville | 40 | D | 0 | — |
| 25 | 21718 | Burkittsville | 40 | D | 0 | $447K |
| 26 | 21721 | Chewsville | 40 | D | 0 | — |
| 27 | 21733 | Fairplay | 40 | D | 0 | $316K |
| 28 | 21759 | Ladiesburg | 40 | D | 0 | — |
| 29 | 21762 | Libertytown | 40 | D | 0 | — |
| 30 | 21767 | Maugansville | 40 | D | 0 | $220K |
| 31 | 21775 | New Midway | 40 | D | 0 | — |
| 32 | 21777 | Point Of Rocks | 40 | D | 0 | $441K |
| 33 | 21778 | Rocky Ridge | 40 | D | 0 | $416K |
| 34 | 21781 | Saint James | 40 | D | 0 | — |
| 35 | 21790 | Tuscarora | 40 | D | 0 | — |
Recommended Buyer Guides for Frederick County
Four sources — EPA, NSF, FEMA, CDC — drive the match.
- Best Lead Paint Test Kits — 58.3% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
Deep Dive Reports
Detailed analysis for Frederick County, Maryland
Overview
Frederick County in Maryland covers 35 ZIP codes with an average Home Safety Score of D (53/100).
13 of 35 ZIP codes have recorded EPA violations. 8 health-based violations have been documented.
← Back to Maryland water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.
What You Can Do
Frederick County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
58.3% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.