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Official EPA SDWIS Verified ReportWater Quality & Testing GuideHistorical Record: No Recorded SDWIS Violations

ZIP Code 20811 Water Quality & Testing Report

Bethesda, MD · Montgomery County County · Updated for 2026

Public Health & Medical Notice: Drinking water quality data on this page reflects historical compliance records submitted under the Safe Drinking Water Act. This information does not constitute medical advice or a real-time safety guarantee. If you are pregnant, nursing, preparing infant formula, or immunocompromised, consult a healthcare provider. Boiling water kills biological pathogens, but does NOT remove chemical contaminants like lead, arsenic, or PFAS.
Quick EPA Verified Answer

Is Tap Water Safe to Drink in ZIP 20811 (Bethesda, MD)?

Caution / Filtration Recommended: Tap water in ZIP code 20811 (Bethesda, MD) has compliance concerns, earning an EPA Safety Grade of C (66/100) due to 0 health violation(s) and 4.4 ppb lead. While treated by Granite Mobile Home Park, residents are advised to use an NSF/ANSI 53 certified water filter for drinking and cooking.

Safety Score
C

Water Safety Grade

Fair — Some compliance concerns

Health Violations

0

Total Violations

0

Lead Risk

N/A

Contaminants

0

About Tap Water in ZIP Code 20811

Tap water in ZIP code 20811 (Bethesda, MD) is distributed by Granite Mobile Home Park (EPA ID: MD0030204), serving approximately 96 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of C with a composite quality score of 66/100.

Water System

Granite Mobile Home Park

EPA ID: MD0030204

Water Source

Ground Water

Population Served

96 residents

County

Montgomery County County, Maryland

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Lead Levels in ZIP 20811

EPA action level: 15 ppb | Public health goal: 0 ppb

Lead Level: 4.4 ppb — Very Low

The 90th percentile lead level in 20811 is 4.4 ppb. This meets the EPA action level of 15 ppb. Health experts recommend a target of 0 ppb for optimal safety.
Lead Level (90th percentile)
4.40 ppb (0.0044 mg/L)
Lead Exposure Risk Rating
Unknown
Note: Lead levels above are the 90th percentile from EPA monitoring — meaning 90% of samples were at or below this level. Even "undetected" tap water lead doesn't account for lead leaching from home plumbing. If your home was built before 1986, individual tap testing is recommended.
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Water Hardness & Mineral Content

Grains per gallon (GPG) & Parts per million (PPM / mg/L)

Classification: Moderately Hard4.9 GPG · 84 mg/L

Water in ZIP 20811 is Moderately Hard (84 mg/L / 4.9 GPG). It contains beneficial natural minerals like calcium and magnesium without causing heavy scale accumulation.

Recommendation: A water softener is optional. Regular maintenance of hot water appliances is recommended.
Hardness (GPG)

Grains per gallon

4.9 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

84 mg/L
Appliance Scaling Risk
Low / Moderate

Official EPA SDWIS Database Entry

Utility: Granite Mobile Home Park · PWSID: MD0030204

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

Granite Mobile Home Park has recorded zero violations in the EPA compliance database over the past 5 years.

Total Violations (5 yr)
0
Health-Based Violations
0
Unresolved Violations
0
Boil Water Advisories
0
Compliance Risk
Low

Regulatory compliance risk for this utility is rated Low based on past reporting and enforcement records.

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Contaminants Detected

Contaminants with health-based violations on record

No health-based contaminant violations are on record for ZIP code 20811 under the Safe Drinking Water Act.

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Water Source & Environmental Factors

Ground Water

This system draws water from underground aquifers. Groundwater is naturally filtered through soil and rock, but can still contain naturally occurring minerals like arsenic, radium, or nitrates.

Water Source Type
Ground Water
EPA Radon Zone

Highest potential

Zone 1

EPA Radon Zone 1 — highest potential for radon in indoor air. Homeowners should test their home for radon and consider mitigation if levels exceed 4 pCi/L.

Water Quality Testing in ZIP 20811

Tap Water & Well Testing Recommendations

Residents in ZIP code 20811 served by Granite Mobile Home Park can test tap water or private well systems to verify water purity. Testing detects hidden contaminants before they impact family health.

Tap Water Testing Steps

  • 1.Conduct a certified lead check if your home was constructed before 1986.
  • 2.Use certified lab testing kits rather than uncalibrated test strips for regulated compliance.
  • 3.Sample water from both your kitchen faucet and water heater to compare line purity.

Private Well Testing Steps

  • •Test for Coliform bacteria and Nitrates annually.
  • •Test for heavy metals, radon, and PFAS every 3 years.
  • •Send samples to a state-certified drinking water laboratory recognized by Maryland Department of the Environment.
Certified Lab Testing: Always use an EPA-certified drinking water laboratory in MD for formal legal or real estate compliance testing.

🛡 What Should You Do? — ZIP 20811 Recommendations

  • ⚠ Use a certified NSF/ANSI 53 filter for drinking and cooking water if you have young children
  • ⚠ Never give unfiltered tap water to infants in formula — use certified bottled or filtered water
  • ⚠ Request a copy of the Consumer Confidence Report to see what was detected and when
  • ⚠ Call the EPA Safe Drinking Water Hotline: 1-800-426-4791

Recommended Water Treatment Systems:

🏺

NSF 53 Lead Pitcher Filter

Specifically certified to reduce lead and copper at the tap.

Lead Filter Guide →
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NSF 58 Under-Sink RO System

Advanced filtration for PFAS, fluoride, nitrates, and organic chemicals.

RO System Guide →

Frequently Asked Questions — ZIP 20811 Water Quality

Is tap water safe to drink in ZIP code 20811?+
Tap water in 20811 (Bethesda, MD) meets major standards but has a grade of C due to minor past violations. Vulnerable populations may want to use a certified filter as a precaution.
How do I get my water tested in ZIP 20811 (Bethesda, MD)?+
To test water quality in ZIP 20811, you can order a certified drinking water test kit or send water samples to an EPA/NELAP certified laboratory in MD. Certified testing checks for lead, coliform bacteria, nitrates, hardness, and PFAS that standard test strips miss. Contact Maryland Department of the Environment for a list of certified regional labs.
How hard is the tap water in 20811?+
Tap water in 20811 is classified as Moderately Hard with an estimated mineral hardness of 84 mg/L (4.9 GPG). A water softener is optional. Regular maintenance of hot water appliances is recommended.
Should I test private well water in 20811?+
Yes. Unlike municipal systems, private wells in 20811 are not regulated by the EPA or local utilities. Private well owners should test their water annually for coliform bacteria and nitrates, and every 3 to 5 years for heavy metals (lead, arsenic) and volatile organic compounds.
What is the lead level in 20811 tap water?+
The 90th percentile lead level in 20811 is 4.4 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 20811?+
There are currently no active boil water advisories on record for 20811. Water treatment systems are operating within normal parameters.
Who provides tap water to 20811?+
Tap water in ZIP code 20811 is provided by Granite Mobile Home Park (EPA ID: MD0030204), serving approximately 96 residents.
What water filter should I use in 20811?+
Based on water metrics for 20811, we recommend None / Standard Pitcher. Look for certifications such as NSF/ANSI 42 (Chlorine, Taste & Odor).

Data Sources & Methodology

Water quality data for ZIP code 20811 is compiled from the EPA Safe Drinking Water Information System (SDWIS), EPA ECHO enforcement database, UCMR5 unregulated contaminant monitoring, and Consumer Confidence Reports filed by Granite Mobile Home Park. Safety scores are composite metrics derived from violation history, lead levels, enforcement actions, and infrastructure risk indicators. Data reflects a 5-year monitoring window. Last dataset update: 2024. View EPA source data →