Bethesda, MD: High Radon Risk — 65/100 (2026)
11 ZIP codes · 2 water systems · Updated 2026-06-03
Public water data for Bethesda, MD reveals a split picture — tap water quality varies meaningfully by service area and the city's grade reflects that variability.
How Bethesda Compares
Data: EPA SDWIS Last verified: 2026-06-03
Water Quality Map: Bethesda, MD
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Score Distribution
Safety grade breakdown for Bethesda's 11 ZIP codes.
Key Facts for Bethesda Residents
- Average lead level: 0.0044 mg/L.
- Estimated remediation: $1,709 per household.
- CDC health risk index: 10.24.
Bethesda's Water Providers
At present, 2 utilities serve the bulk of Bethesda, MD's residential water connections out of 2 systems active in the area, spread across independent providers with separate infrastructure and compliance obligations.
Overview
We track water quality and home safety data for 11 ZIP codes in Bethesda, Maryland (population ~86,851), covering 2 community water systems serving approximately 1,900,096 people region-wide.
No EPA violations recorded across any ZIP codes in Bethesda — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Bethesda: C (65/100)
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
Bethesda water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0044 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
- Zone 1 (High): 11 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 20810 | C | Granite Mobile Home Park | 96 |
| 20811 | C | Granite Mobile Home Park | 96 |
| 20813 | C | Granite Mobile Home Park | 96 |
| 20814 | C | WASHINGTON SUBURBAN SANITARY COMMISSION | 1,900,000 |
| 20816 | C | WASHINGTON SUBURBAN SANITARY COMMISSION | 1,900,000 |
| 20817 | C | WASHINGTON SUBURBAN SANITARY COMMISSION | 1,900,000 |
| 20824 | C | Granite Mobile Home Park | 96 |
| 20827 | C | Granite Mobile Home Park | 96 |
| 20889 | C | WASHINGTON SUBURBAN SANITARY COMMISSION | 1,900,000 |
| 20892 | C | WASHINGTON SUBURBAN SANITARY COMMISSION | 1,900,000 |
All ZIP Codes in Bethesda
- 20810 [C]
- 20811 [C]
- 20813 [C]
- 20814 [C]
- 20816 [C]
- 20817 [C]
- 20824 [C]
- 20827 [C]
- 20889 [C]
- 20892 [C]
- 20894 [C]
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.
Bethesda Community Health Snapshot
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
How Remediation Costs Compare in Bethesda
At current valuations, Bethesda sits in the low remediation-share tier — the equity impact of fixing documented issues is proportionally minor.
Remediation costs in Bethesda are relatively low compared to home values. The $1,127–$2,282 estimated range is a small fraction of median property value. Home values are 167% above the Maryland average.
Bethesda: Lead Risk & Vulnerable Populations
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.
Lead risk in Bethesda appears low overall, but individual homes may differ. Testing is the only way to confirm your water's lead content.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Bethesda: Flood History & Water Damage Risk
The National Flood Insurance Program captures decades of claims at the local level, building a record of cumulative community flood exposure. For Bethesda, that record documents 133 claims and 27% 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.
Bethesda has a moderate flood history with 133 FEMA claims averaging $6,726 per payout. 27% 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>$1,709</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 Bethesda
- 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. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
Deep Dive Reports
Detailed analysis for Bethesda, MD