Her remodeled home has a beautiful view of Duck Creek. That's more than twice the federal limit. But if my neighbors were to hear me say this, they wouldn't like it. In the town survey, levels above 5 ppm showed up in 87 of the 239 private wells tested. That is above the amount allowed for new construction and redevelopment under the town's local comprehensive plan, and is the limit endorsed by the Cape Cod Commission.
Nitrates also occur naturally in rainfall.
Cambareri said the level for all of Cape Cod for naturally occurring nitrates is less than a half of 1 ppm. At 1 to 3 ppm, Cambareri said septic system nitrates are almost certainly infiltrating drinking water. At 10, you're almost drinking water from an effluent plume. Two businesses, Uncle Franks restaurant and the Wellfleet Harbor Actors Theater, had nitrate levels over the federal limit of 10 parts per million. A nearby cottage colony that shared the same well as the businesses also tested high.