Inspections of water systems serving 10,000 Washington state farm workers and their families in 1999 revealed few instances of pesticide contamination, according to a report released by the state Department of Health.
Last summer and fall, department staff inspected and tested the water supplied by 150 public water systems serving 189 temporary farm worker facilities statewide.
Only two water samples, (1 percent) of the total exceeded drinking water standards for pesticides.
Secretary of Health Mary Selecky said last year's testing and inspections was the most extensive effort ever for a single category of water systems.
"Ensuring the availability of safe, reliable drinking water is a critical part of improving conditions for the states' temporary farm workers and their families," said Selecky.
The effort was launched last year in response to a request last year by Gov. Gary Locke, who asked the department to evaluate whether current testing requirements -- particularly for pesticides -- are adequate to protect the health of temporary farm workers.
While the testing discovered few instances of pesticide contamination, it was revealed that more than half of the systems inspected require some improvement to protect public health.
"The most common problems we found during the inspections were poorly constructed old wells that were in bad locations in the first place, and inadequately maintained, deteriorating drinking water facilities," Selecky said.
"These conditions can allow bacteria and other contaminants to reach drinking water."
The department has initiated enforcement effort to make sure all problems are corrected before facilities are licensed this year.