Derwood, MD: High Radon Risk — 53/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Across water systems in Derwood, EPA data shows a below-average compliance pattern for MD — health-based violations are on file in several areas, and checking the specific system serving your address is a practical first step for concerned residents.
How Derwood Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Derwood Water
- Homes built before 1986: 61% — older plumbing may contain lead solder.
- Estimated remediation: $2,900 per household.
- CDC health risk index: 10.24.
Who Supplies Your Water in Derwood
Water delivery in Derwood, MD is handled by 2 utilities rather than a single system — drawn from 2 providers in federal records, each filing its own compliance reports and setting its own rates.
Overview
We track water quality and home safety data for 1 ZIP code in Derwood, Maryland (population ~16,557), covering 2 community water systems serving approximately 1,900,096 people region-wide.
No EPA violations recorded across any ZIP codes in Derwood — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Derwood: D (53/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Derwood water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Derwood
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 20855 | D | WASHINGTON SUBURBAN SANITARY COMMISSION | 1,900,000 |
All ZIP Codes in Derwood
- 20855 [D]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Derwood
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Housing & Infrastructure in Derwood
With 61% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Heavily weighted toward older construction, Derwood's housing stock carries a median build year of 1987. That profile puts a majority of homes in the era when lead-soldered copper plumbing was standard practice.
Over half of homes in Derwood were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Derwood Homeowners
Equity impact data for Derwood lands in the favorable tier — remediation claims a small slice of what properties here are worth.
Remediation costs in Derwood are relatively low compared to home values. The $1,900–$4,100 estimated range is a small fraction of median property value. Home values are 44% above the Maryland average.
Lead Exposure Risk for Children in Derwood
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Routinely in Derwood, where 61% of housing predates the solder ban and aggregate utility readings hover near the federal threshold, a faucet-level draw functions as a standard household step for families with small kids.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Derwood
The National Flood Insurance Program captures decades of claims at the local level, building a record of cumulative community flood exposure. For Derwood, that record documents 10 claims and 100% of ZIP codes inside FEMA-designated flood zones. What makes those numbers relevant to water quality is the set of mechanisms flooding activates: heavy precipitation that floods treatment intake zones can introduce contaminants upstream of normal filtration; well casings in low-lying areas can be infiltrated by floodwaters carrying bacteria, sediment, and chemical residue; and distribution system pressure changes during flooding can create backflow conditions. These effects become more probable as flood frequency and magnitude increase — and the NFIP record indicates both are meaningful factors locally.
Derwood has a moderate flood history with 10 FEMA claims averaging $1,180 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,900</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Derwood
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. With 61% of homes built before 1986, lead solder is a real possibility.
- Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.
Deep Dive Reports
Detailed analysis for Derwood, MD