WAILUKU, Maui — Facing an almost certain veto override, Maui Mayor Alan Arakawa yesterday announced he would let a bill banning use of Hamakuapoko well water for human consumption become law without his signature.

The two wells in question tap into groundwater that contains harmful agricultural chemicals. Water from the wells is filtered through a granulated activated carbon system, meeting federal and state standards for maximum contaminant levels.

Administration plans to pipe treated water from the Hamakuapoko wells to Pa'ia consumers, who get their water from uncontaminated wells in the West Maui Mountains, was met with strong opposition. The mayor accused those who questioned whether the water was truly safe of fear-mongering and of letting emotion push science aside.

Arakawa last week assembled a panel of three experts in an attempt to assure Pa'ia residents that treated water from the Hamakuapoko wells is safe. The panelists noted that the same granulated activated carbon filtration system has been in use for 20 years at Central O'ahu wells, providing water to 200,000 residents. But their comments did little to quiet the concerns.

Arakawa said yesterday that vetoing the bill would have led to "more contentious, emotionally driven arguments," and that he had not been given any indication the council would let a veto stand. Council members had voted 6-2 to pass the bill; six votes are needed for a veto override.

"I have made every effort to deal with this subject in a rational, objective manner. However, given the amount of effort by certain County Council members and members of the public to create a climate of fear about our water system, I believe the best course of action to take right now is to allow this subject to rest," Arakawa said in a statement.

Councilwoman Michelle Anderson of South Maui, chairwoman of the Water Resources Committee and the council's most vocal critic of administration plans to use the Hamakuapoko wells, said yesterday the council would not have gone so far as to pass the bill if Arakawa had been sensitive to community concerns about water quality from the start.

Anderson said the fields above the groundwater sources continue to be actively farmed and exposed to chemicals. Although contaminants such as DBCP (1,2-dibromo-3-chloropropane), EDB (ethylene dibromide) and TCP (1,2,3-trichloropropane) have been identified in the wells, Anderson insists that not enough testing has been done to determine whether other toxic substances are present, or what the health effects are from exposure to a mix of contaminants.

The Hamakuapoko wells are not in regular use, but have provided emergency supplies for the Upcountry water system during drought emergencies. Under the bill passed last month by the council, that cannot happen again.

Arakawa said taking away the option of using the Hamakuapoko water in drought emergencies "is a serious mistake." He also noted that the county invested $12 million in the Hamakuapoko wells, and the question remains of what to do with those facilities.

Anderson said the county should work out an agreement to "trade" the Hamakuapoko water for surface water collected by agricultural companies.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.