Dennis Water District, MA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2021-2023). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
About Dennis Water District
Dennis Water District serves about 65,000 people through 14,626 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Barnstable County, Massachusetts. EPA system ID: MA4075000; phone on file: 5083983351. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
Against the period ending 2020 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Dennis Water District is 1 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2017 | 1 ppb |
How Dennis Water District compares
Of the 535 Massachusetts systems with a lead result, the median latest reading is 1.7 ppb; 13 are over 15 ppb right now and 66 have gone over at some point. Dennis Water District's reported as 0 (not detected) sits at the 24th percentile in Massachusetts and the 40th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
29 other systems share Barnstable County; 21 of them have a higher latest lead result than Dennis Water District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Falmouth Water Dept | 97,551 | 1.1 ppb |
| Upper Cape Regional Water Cooperative | 56,250 | - |
| Centerville Osterville Marstons Mills Wd | 50,000 | 1.82 ppb |
| Harwich Water Department | 39,144 | 0 (not detected) |
| Yarmouth Water Department | 38,900 | 1.5 ppb |
| Mashpee Water District | 36,922 | 1.4 ppb |
| Hyannis Water System, Town Of Barnstable | 35,000 | 0 (not detected) |
| Brewster Water Department | 35,000 | 3.4 ppb |
| Chatham Water Department | 30,000 | 1.05 ppb |
| Sandwich Water District | 23,000 | 0 (not detected) |
Next steps for South Dennis, MA
Look up your address in Dennis Water District's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Dennis Water District whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. A zero today does not rule out a jump later - the rules are tightening in 2027.