The product leaving the Coupeville water treatment plant is now the purest it’s ever been. And within about a month, people might start tasting the difference, according to town Utility Superintendent Joe Grogan.

A new filtration system has pumped approximately two million gallons of water in about a week, he said.

The system, paid for by the Navy, reduces per- and polyfluoroalkyl substances, known as PFAS, to non-detect levels and removes other organic compounds.

The PFAS chemicals are found in firefighting foam used by the Navy for petroleum-based fires and are linked to health issues including certain types of cancer, according to the Environmental Protection Agency.

Tests results from both the town and a Navy contractor have shown the new granular activated carbon system is meeting expectations, Grogan said. However, it will take some time before the new water replaces what is currently in the reservoirs and people might start noticing the difference, Grogan said.

The new method, which is done in addition to the town’s existing filters that remove iron and manganese, also removes hydrogen sulfide, he said. This gas can cause water to have a rotten egg odor or taste.

Only one of the two filtration sets are currently online at the plant, which is still under construction. The second set will increase the plant’s capacity.

The rest of the pumps, both filtration sets, the electrical work and the building construction are all expected to be complete by the end of September, Grogan said.

The town will perform regular checks for the PFAS family of chemicals using the most recent test methods available. The tests approved by the EPA are consistently increasing the number of PFAS that can be tested for, Grogan said.

The method approved by the EPA that the town most recently used tested for 18 possible PFAS compounds. There had been five PFAS compounds found in Coupeville’s water, all of which were removed to non-detectable levels by the filtration system.

Test results are available on the water utility page of the town’s website.

Construction on service connections to properties with wells that tested above the EPA’s lifetime advisory level is expected to begin next month, according to a Navy press release.

The residents should be connected to town water by the end of November.

“This really is an extraordinary accomplishment for the project team to have designed and constructed this system in this amount of time,” Capt. Matt Arny, NAS Whidbey Island’s commanding officer, said in a statement.