If you’re tired of feeling guilty about driving a gas-guzzling car or cranking up your air conditioning, you could just try hanging your head in shame about that bottle of spring water you are sipping instead.

Yes, the foes of bottled water are at it again, this time in the form of an advertising campaign that aims to promote tap water and underscore the environmental costs of producing and disposing of plastic water bottles.

Tappening, a group that opposes bottled water, is spending $250,000 on a media campaign to promote its cause. Tappening is a joint venture of ad agency DiMassimo Goldstein and public relations firm Ericho Communications. It most recently launched a campaign called “Message in a Bottle” that aims to deliver one million empty water bottles to incoming Coca-Cola CEO Muhter Kent.

The campaign is the latest of many recent attacks on bottled water, including the urging of boycotts by the mayors of cities including London, San Francisco and Seattle.

“We can use our advertising and public relations abilities to un-sell bottled water hype,” said Tappening’s Mark DiMassimo.

The ads will appear as “wild postings” on construction sites in ten U.S. cities as well as in magazines and community newspapers, the group said. The ads claim that last year, plastic bottles generated more than 2.5 million tons of carbon dioxide and that every year, 38 million bottles end up buried in the ground.