Pollution levels from an industrial solvent are again dropping at the Hanley Avenue well.

Tests show trichloroethylene levels at about 4 parts per billion in the city’s most productive drinking water well as of late August. Last May, city tests showed 7 parts per billion. Also in May, Panhandle Health District tests found more than 8 parts per billion.

The city shut off the well but restarted it when summer water demand rose. And as pumping increased, the levels of trichloroethylene dropped, said city water superintendent Jim Markley.

The Hanley Avenue well has supplied all of the city’s water during past winters. This year, it will likely be taken off line for the winter at the end of this month.

Markley wants to wait until it’s clear Coeur d’Alene will have no more long stretches of warm weather - resulting in high water demand.

He also is awaiting the completion of a new well on Honeysuckle Avenue to cover potential demand.

The city of Pocatello, meanwhile, is going to the Idaho Department of Water Resources Sept. 26 for help dealing with trichloroethylene. It is asking the board to issue $1.4 million in bonds to remove the solvent from its drinking water, also drawn from underground wells.

Pocatello has studied the pollution problem since 1989. It comes from a landfill south of the city where barrels of trichloroethylene were dumped in the 1960s and are presumed to be leaking.

City and state officials could not be reached for information on the levels of pollution in the Pocatello wells.

Coeur d’Alene hasn’t asked for similar assistance because the trichloroethylene levels in the Hanley Avenue well haven’t exceeded federal safe drinking water standards, Markley said. In addition, “the cost of removing TCE from this well is about the same as drilling a whole new well.”

Trichloroethylene levels would have to exceed 5 parts per billion for a year to cross the federal threshold and could mean the well would be closed.

, DataTimes MEMO: This sidebar appeared with the story: ELSEWHERE The city of Pocatello next week will ask the Idaho Department of Water Resources for $1.4 million to remove trichloroethylene from its drinking water.