NEW YORK (AFP) - Water, water everywhere - just not in plastic bottles, says a town in the US state of Massachusetts.

A law passed by the town of Concord went into effect with the New Year, making single-serving bottles of water illegal.

The ban is intended to encourage use of tap water and curb the worldwide problem of plastic pollution.

It only applies to "non-sparkling, unflavoured drinking water." Coke or other soft drinks are exempt.

Ms Jean Hill, an 84-year-old activist, thought up the ban, arguing that bottles fill garbage dumps, while consumers are lured into drinking water they could obtain for a tiny fraction of the cost at their own sink.

"The bottled water companies are draining our aquifers and selling it back to us. I'm going to work until I drop on this," Ms Hill told The New York Times in 2010.

First time offenders get a warning. Anyone caught selling the banned bottles a second time will be fined US$25 (S$31), and US$50 thereafter.