The Navy is providing bottled drinking water to two homes on Central Whidbey and at least one on North Whidbey after preliminary tests showed the level of potentially harmful chemicals exceeded the lifetime health advisory set by the Environmental Protection Agency.

A retired Navy doctor, who asked not to be named, said he and his wife were alerted to the test results Friday afternoon and soon afterward Navy officials showed up with bottled water.

“I about fell off my chair,” he said. “It was like a gut punch.”

The couple has lived in their home about three-quarters of a mile from the Navy’s Outlying Field Coupeville for 17 years.

The man said their well tested at six times the advisory level for perfluorooctanoic acid, or PFOA. Testing for the other chemical, perfluorooctane sulfonate, or PFOS, was inconclusive and has to be done again; a positive result could further increase the overall level, he said.

He said his neighbor’s well also tested at far beyond the advisory level.

Testing done independent from the Navy found the presence of PFOA in a Town of Coupeville well that is near OLF Coupeville, a Navy touch-and-go runway in Central Whidbey, but the amount was below the advisory level, the town reported.

The testing at many Navy bases nationwide is in response to the EPA’s issuance earlier this year of lifetime health advisory levels on the two perfluoroalkyl substances, PFOA and PFOS, at 70 parts per trillion, individually and combined. Both of these chemicals are in “aqueous film forming foams,” or AFFFs, a synthetic firefighting foam that’s used to put out petroleum-based fires, especially those that occur in airplane accidents. Firefighters on base used the foam in practice and on real fires.

The Navy is conducting tests of drinking water wells in areas of a mile radius of Naval Air Station Whidbey Island’s Ault Field base and the Outlying Field Coupeville in Central Whidbey. Navy officials said they would find an alternative source of drinking water for anyone with a well that tested beyond the advisory level, provided the Navy is the source of the contamination.

Earlier this year, the Navy tested a well at the site of a former firefighter training school at the corner of Sullivan and Degraff roads on the north side of the base and found that the amount of the chemicals in the water was above the advisory level, according to Doug Kelly, hydrogeologist with Island County. The site is one of several Superfund sites on the base.

The Navy hasn’t tested groundwater at the current training site near the Navy hospital since there isn’t a well there, he said. But private wells within a mile of the site are being tested.

A test of a well at OLF Coupeville found the presence of PFOA, but not above the advisory level. The Navy has no record that the firefighting foam was ever used at the field.

The Navy has received results for 34 private wells so far, with three testing above the advisory level. They will be retested to check the accuracy of the initial test.

Navy officials hope to test many more wells — a total of 170 — in North and Central Whidbey, but property owners’ response to the Navy’s request to access their wells has been slow so far, according to Leslie Yuenger, public affairs officer for Naval Facilities Engineering Command Northwest.

“In order to protect property owners from potential continual contamination and to discover the breadth of the situation, we need those property owners who received a letter from the Navy to respond to our letter,” she said in an email.

The Navy isn’t releasing details about how high the levels of chemicals are in the two wells until an open house meeting in mid-February; all of the testing results are expected to be in by then, Yuenger said.

Kelly said the testing results will give hydrogeologists a good idea of flow direction in the aquifer as well as the central point where the flow radiates from.

The Town of Coupeville worked with the state Department of Health to conduct independent testing of its wells; the Navy is also testing the wells.

Two samples taken at the Keystone well, which is near OLF Coupeville, showed PFOA levels at 62 parts per trillion and 59 parts per trillion, both of which are below the advisory level of 70 ppt. No PFOA was detected at the three wells at Fort Casey. No PFOS was detected in any of the wells, according to a press release from the town.

The water from all the wells is blended before it gets to residents’ faucets. Two tests taken of the blended water showed levels at 25 and 27 parts per trillion.

Once all the results are in, Navy experts will investigate to determine the cause of the contamination, Yuenger said.

Officials said it’s possible contamination isn’t from firefighting foam. Both PFOA and PFOS were used in a large variety of other things, including nonstick pans, carpet-protecting spray and food wrappers. Nearly everyone has the chemicals in their blood, according to Barbara Morrissey, a toxicologist with Office of Environmental Public Health Sciences of the state Department of Health.

Still, it’s relatively rare for the compounds to be present in drinking water. The EPA did a study of public water systems across the nation and found detectable levels present in only 4 percent; an even smaller percentage of systems tested above the advisory level, Morrissey said.

Morrissey said the department advises anyone with a well that tested above the advisory level to stop drinking well water. Still, she explained that the advisory level was set very low as a worst-case scenario, assumes that someone is consuming the same level of the chemical over a lifetime and is based on the water consumption of a pregnant woman — which is larger than average.

In addition, she said studies of the health effects of the chemicals are not clear. Tests of lab animals showed the possibility of serious health problems, but studies of humans exposed to the chemicals are not conclusive. One thing the studies seem to agree on, she said, is that the chemicals may affect the liver and increase cholesterol.

Navy officials wouldn’t say whether any results have come in from North Whidbey wells yet. Resident Sharon Stone said she is waiting to hear from the Navy.

Stone said the people who did the testing didn’t inspire confidence. In the past, she’s had her well tested by people who wore “white suits” and followed an extended procedure. The people sent by the Navy, she said, didn’t have any cards or name tags identifying them as the testers and quickly grabbed a couple of samples from a faucet on her holding tank.

“I definitely wasn’t impressed with them,” she said.