About 600 families in Fauquier County are investigating the possiblity of switching their water and sewer service from the town of Warrenton, which now provides for them, to the county system because they say their rates are too high, a community spokesman said last week.

The town charges the families, who live outside of its boundaries, 50 percent more for water than it charges in-town residents. The 600 homes account for almost one-third of the town's water customers.

Community spokesman Richard M. Galecki said the out-of-town customers, most of whom live in a subdivision called Warrenton Lakes, did not realize they were being charged 50 percent more for water than in-town residents until the Warrenton Town Council raised water rates for everyone during the summer to help pay for a $2 million water treatment plant.

The out-of-towners complained to the council, which set up a study committee and then, a week ago, voted to keep the 50 percent rate difference.

With the rate increase, an out-of-town family of four now pays $100 for a month's worth of water that would cost the same family $50 if they lived in Warrenton.

"Because we don't live in Warrenton we cannot vote for the council members," said Galecki. "Therefore they seem to feel they can treat us unfairly."

However, town officials and council members say the 50 percent rate difference is fair because the out-of-town residents do not share the legal liabilities that in-towners bear.

"If we default on the debt for the new plant, then our residents will have to pay out of their taxes," said Town Manager E.L. Brower. "This is a service provided by Warrenton for Warrenton residents. If others want that service then they should expect to pay more."

Brower said it is not unusual for towns and cities throughout the country to charge out-of-town residents more than their own residents for the same services.

Furthermore, he said, the town made an agreement 10 years ago with Warrenton Lakes' original developer, who has since defaulted, that the town would provide water and sewer services at a 50 percent increase over normal rates.

Since the Warrenton Lakes residents cannot vote against the council members, they say they have set up committees to investigate possible legal action and the switching to the Fauquier County water service.

This latter move could be a serious blow to Warrenton, which gets almost half of its revenue for the pay-as-you-go water treatment plant from out-of-towners.

The switch could also be expensive for the out-of-town residents, who would be expected to pay most or all of the costs of running a hookup from county water lines to their community. Galecki said the group does not know how far the pipes would have to run or what it would cost.

An earlier idea for the families to boycott Warrenton businesses has been discarded, he said.

Galecki said the residents are taking advice and encouragement from the leaders of a community with an almost identical problem near Palatine, Ill.

Residents in a subdivision there were paying $6.23 for 1,000 gallons of water, which cost Palatine residents 95 cents. After a three-year fight, an Illinois state judge recently ruled that the residents' bills should be cut by half.