C41/100
South Dennis Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 65,000 residents · Massachusetts
What's In South Dennis's Tap Water?
66
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2014.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
DENNIS WATER DISTRICT
Population Served
65,000
Water Source
Groundwater
System ID
MA4075000
Frequently Asked Questions About South Dennis Water
Is South Dennis tap water safe to drink?
South Dennis, Massachusetts tap water receives a grade of C (41/100), which is considered fair. 0 contaminant(s) exceed EPA maximum contaminant levels and 39 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in South Dennis's water?
66 contaminants were tested in South Dennis's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does South Dennis have any water quality violations?
Yes, South Dennis has 39 EPA violation(s) on record, with the most recent in 2014. Violation types include MR, MCL. 5 of these are health-based violations, which are the most serious category.
Do I need a water filter in South Dennis?
South Dennis water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. All contaminants are within health goals.
Where does South Dennis's tap water come from?
South Dennis's drinking water is sourced from groundwater and supplied by DENNIS WATER DISTRICT. The system serves approximately 65,000 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is South Dennis's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. South Dennis's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does South Dennis's water compare to other cities in Massachusetts?
South Dennis's water quality score of 41/100 earns a grade of C, which is considered fair. This is a below-average score that indicates room for improvement. Visit our Massachusetts state page to see how all cities in the state compare.
What should I do if I'm concerned about South Dennis's water quality?
If you have concerns about South Dennis's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (DENNIS WATER DISTRICT) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.