The situation has forced the closure of the school until further notice. Students had a scheduled day off tomorrow, but teachers will report to Kahaluu Elementary School.

Also, about 300 Waiahole Valley residents were advised to boil their drinking water following the discovery of the disease-causing E. coli bacteria in the distribution system, state officials said.

A test of the water quality in the privately operated system found traces of E. coli bacteria in water pipes at the school, Health Department officials said.

The test was ordered Tuesday after officials noticed that a chlorinated pump in the area had failed, said Adrienne Gardner, housing information specialist for the Hawaici Housing Finance and Development Corp., which owns, operates and maintains the water supply system in the mostly agricultural Windward O'ahu valley through a contract with a private engineering firm.

The Escherichia coli bacteria is often an indicator of potential fecal contamination in water, and its presence at any level triggers an immediate boil water notice, officials said.

An estimated 73,000 cases of infection and 61 deaths occur each year from the hundreds of different strains of the bacterium, according to the national Centers for Disease Control and Prevention. Infection often leads to bloody diarrhea, and occasionally to kidney failure. Infection can occur after eating undercooked meat, drinking raw milk or swimming in or drinking sewage-contaminated water.

Officials suspect the problem in Waiahole arose in a contaminated pipe somewhere within the distribution system rather than at the drinking water well that serves the area. Officials tested sites up and down the distribution system today to find the source of the contamination, Gardner said.

Department of Education officials said Waiahole Elementary School, which serves about 95 students, will remain closed until the water problem is resolved.

The Waiahole Elementary cafeteria also prepares food for Ka'a'awa Elementary School and other sites. If the Waiahole Elementary remains closed beyond tomorrow, arrangements have been made for food preparation to come from Kahalu'u Elementary School.

Gardner said the housing agency has ordered a new chlorinated pump for the system and hopes to have it installed by the end of this weekend.

The Waiahole water system is one of about 50 privately operated systems on O'ahu, mostly in remote areas, and is the only one operated by the housing agency, she said.