PORTSMOUTH — More than three months after it was first enforced, a boil-water advisory is still in effect for customers of the Prudence Island Water District (PIWD).

The R.I. Department of Health (DOH) issued the order in early October 2018 after a routine sample taken from the storage tank on Sept. 27 came back positive for total coliform and E. coli. Subsequent tests revealed levels of total coliform in the system, but not E. coli.

Customers of the entire water district — as many as 700 residents — were impacted, according to DOH. Residents on private wells or on Prudence Park Water Coop are not affected. 

The source of contamination has been traced to island “snowbirds” who used compressed air to back-flush their plumbing systems while winterizing their cottages and homes, Town Administrator Richard Rainer, Jr. said at a meeting in November.

The topic came up again during a joint session on legislative priorities between the Town Council and School Committee Monday night, when Sen. James Seveney (District 11) asked Mr. Rainer if there was a plan in place to resolve the issue.

“The short answer is no. They’re going to have to install back-flow preventers. Until that’s done, I don’t think this is going to be resolved,” said Mr. Rainer, adding he’s been in discussions with island officials on how to implement the installation of the devices.

While back-flow preventers are “not that expensive,” the method of funding the upgrades will surely be a topic of discussion during the council’s annual excursion to Prudence Island this summer, he said.

The state has kept the boil-water order in place despite several successful water quality tests, the administrator said.

“They have received good tests, but right now this has been going on for so long it’s not good enough. They need to fix the system,” he said. “I think, for the most part, we’re boiling good water.”

Council member Keith Hamilton said he has tried in vain to find a surplus tanker truck that could bring potable water to the island. The town has been supplying islanders with some drinking water during the advisory.