Water Quality in Southwest Harbor, ME: 4 Violations — Grade C
Grade C · Score 65/100 · 1 water system · Updated 2026-05-03
Southwest Harbor's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
The public EPA compliance record for Southwest Harbor, ME holds 4 documented water violations — sourced from the federal Safe Drinking Water Information System, which tracks every reportable event for registered public water systems in the state.
Water Quality by ZIP Code in Southwest Harbor
Water quality varies across Southwest Harbor's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 04679 | C | 65 | 4 | 0 | View report → |
Water Quality Overview
Southwest Harbor, Maine receives a water quality grade of C with an overall score of 65 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 1 water system serving Southwest Harbor have accumulated 4 EPA violations (all monitoring/reporting type). These violations are tracked across 1 ZIP codes serving approximately 2,480 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Southwest Harbor's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Southwest Harbor water systems is 0.0021 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 68% of homes built before 1986, Southwest Harbor has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Radon Risk
Southwest Harbor is in EPA Radon Zone 1 (High risk). The EPA recommends all homes in Zone 1 areas be tested for radon. Radon is the second leading cause of lung cancer after smoking.
Water Systems Serving Southwest Harbor
Southwest Harbor is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 2,480 people across 1 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 10 enforcement actions against water systems serving Southwest Harbor. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Southwest Harbor
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Southwest Harbor Water Systems
The following contaminants have been detected or caused violations across Southwest Harbor's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | N/A | 1 | 1 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 1 | 1 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 1 | 1 | No |
| Lead and Copper Rule | Treatment Technique | N/A | 1 | 1 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Southwest Harbor. Recent actions:
| Date | Action Type |
|---|---|
| 2024-02-20 | State Filed Judgment |
| 2023-04-18 | State Order Extension |
| 2023-03-13 | State Filed Judgment |
| 2022-10-18 | State Filed Judgment |
| 2022-10-18 | State Informal Enforcement |
| 2022-09-28 | State Order Extension |
| 2022-05-23 | State Order Extension |
| 2022-03-14 | State Filed Judgment |
| 2021-06-08 | State Informal Action |
| 2021-03-17 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2024-02-20.
Southwest Harbor vs. Nearby Maine Cities
How Southwest Harbor's water quality compares to similar cities in Maine:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Southwest Harbor | C | 4 | 1 | 2,480 |
| Bass Harbor | D | 0 | 1 | 2,480 |
| Bernard | D | 0 | 1 | 2,480 |
| Frenchboro | D | 0 | 1 | 2,480 |
Common Questions About Southwest Harbor Water
These are the most common questions residents search for about water quality in Southwest Harbor, Maine:
Is Southwest Harbor water hard or soft? Water hardness varies by source. Southwest Harbor's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink Southwest Harbor tap water? Southwest Harbor's water receives a grade of C (65/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Southwest Harbor? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Southwest Harbor vs. Maine Average
Understanding how Southwest Harbor compares to the broader Maine average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Southwest Harbor.
ZIP Codes in Southwest Harbor
Southwest Harbor spans 1 ZIP code. The ZIP with the lowest water quality score is 04679. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
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
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.