Hillsboro is coming under increasing state pressure to chlorinate its drinking water because tests continue to find traces of coliform bacteria in it, according to Mayor Alexander Muir.

The water comes from a mountainside spring and is piped to about 30 of the town's 40 homes. The source of the contamination: "Probably . . . deer or wild animals," says Muir.

State health officials "have been pressuring us to chlorinate the water," he said. "But we've been drinking this water for more than 100 years and nobody's gotten sick.

"We had some bad tests last year, in November and December, but the January samples were 100 percent pure. We just took some more samples at homes and at the spring and we'll wait and see how they turn out. They will be the key."

Chlorination would change the taste of the spring water and cost the town about $10,000, said Muir, who has a small goat farm near the center of town.

The cost is not a factor because the town has budgeted money since 1979 to improve its water system. But the town, where no houses have been built since 1899, has a reputation for being averse to change and believes chlorination is unnecessary.