Water district officials note that the wells in question were not regularly being used to provide water for HBWD customers during the first quarter.
It was not tested during the first quarter of 2017, as the Health Department had requested, but it also provided no water to the district’s system.
But Well 1-2 was used little after the October 2016 test; it was not used from early October through early June 2017, with the exception of one day in January.
The next time the well was tested, was between June 28 and July 14, the reading had jumped above the EPA threshold, at 85.89 ppt.
Well 1-3 was tested three times in 2016, with the results falling below the 70 ppt threshold each time.
D&B Principal Engineer Anthony Conetta, who has decades of experience monitoring water districts, and Warren Booth, a maintenance crew leader for the water district, explained during a Town Board work session earlier this month that the failure to test the wells in the first quarter of 2017 was an oversight.
Mr. Conetta and Mr. Booth also explained during the May 10 work session that because the chemicals are unregulated, the district was not obligated to turn off the wells.
No fines can be issued for serving customers water with unregulated chemical contamination, because the threshold is only advisory.
After the contamination was detected and the wells were shut off last year, the town purchased and installed carbon filtration systems for the wells—costing about $1 million—to keep the unregulated chemicals out of the water.
Mr. Conetta stressed that the district had “mostly complied” and pointed out that it had acknowledged mistakes that would not be repeated in the future.

The Hampton Bays Water District has filed a lawsuit against the makers of chemicals that have contaminated wells in the hamlet claiming the companies knew the compounds were toxic and would not biodegrade.
The lawsuit, filed in state Supreme Court last Wednesday, names The 3M Co., Buckeye Fire Equipment Co., Chemguard Inc., Tyco Fire Products LP and National Foam Inc., all of which sold aqueous film-forming foam containing perfluorinated compounds (PFCs).
“Defendants knew it was substantially certain that their acts and omissions .
would cause injury and damage,” states the lawsuit filed by Manhattan-based law firm Napoli Shkolnik.
The state Department of Environmental Conservation was investigating the Hampton Bays Fire Department as the cause, but it is not clear if a determination has been made.
Three of the 11 wells in the district, which serves 7,000 households and withdraws one billion gallons from the aquifer annually, were found to be contaminated with PFCs and have since been taken offline, according to the suit.
Contamination was discovered in the other two wells in 2017, with one taken offline in July and the other in September of that year.
Exposure to the perfluorinated compounds can affect the immune system and fetal health and development, as well as cause liver damage, cancer and thyroid problems, the U.S. Environmental Protection Agency has said.
However, the companies are jointly responsible because they “actually knew of the health and environmental hazards which PFOA [perfluoroocatanoic acid] and PFOS [perfluorooctanesulfonic acid] posed” and conspired to conceal that information from the public, the lawsuit states.
Representatives from 3M, Buckeye and National Foam did not respond to a request for comment.