Water utilities would get earlier warning of viruses, bacteria or chemicals that could be introduced into drinking water systems by terrorists under a test monitoring program set for expansion beyond Cincinnati.

The pilot program ordered by the Department of Homeland Security in response to the Sept. 11 terrorist attacks uses continuous monitoring of public water for contaminants that could sicken or kill millions of people. Some utilities only do spot checks now for such germs, pesticides or radioactive materials.

Some utilities might find that they need additional video cameras and alarms to warn of intruders at water tanks or other sites. Once the pilot program is complete, the Environmental Protection Agency hopes to have a national water security model that utilities could adopt at their own expense.

"Water supplies are very, very accessible targets for biological or chemical weapons," said Donna Schlagheck, a Wright State University political scientist who specializes in American foreign policy and international terrorism. "There are so many potential targets—whether you are taking water from the ground or a river or a lake—and the vulnerability there is enormous."

The monitoring also could detect unintentional contamination and could help utilities improve their overall water quality, said Dan Schmelling, project coordinator for the EPA's Water Security Initiative. Such contamination could include pollution from chemicals spills in lakes or rivers.

The agency and the Greater Cincinnati Water Works began the $11 million test project in 2006, and it took about a year and a half to install the equipment, including sensors placed in the water distribution system at strategic points that feed information to computers for analysis.

Recently, the EPA provided a $12 million grant to New York City to add that city's water system as a second pilot, and three other cities to be announced this year would get similar grants.

The sensors track water characteristics such as clarity and chlorine levels.

"For example, we know what the anticipated amount of chlorine would be, and if a decrease shows up that could mean that something had been added that was consuming the chlorine," said David Hartman, assistant superintendent with the Greater Cincinnati Water Works' water quality and treatment division.

"The EPA developed an ideal system and we compared that to what we had, identifying what was missing and what we could add," Hartman said.

The system also calls for development of a network of laboratories that could analyze water samples if there is suspected contamination. And a computer program that would allow more comprehensive monitoring of consumer complaints, emergency calls and public health agency complaints for clues indicating a widespread problem.

The equipment is operating and collecting the information in the Cincinnati water system, but officials still need to determine how well the project is working and how it can be applied in other cities, Schmelling said.