Voluntary water quality markets, where businesses pay farmers and others to reduce their water pollution, have great potential for addressing a growing problem -- but only if the demand can outpace concerns about hazy regulations and high prices.

A cornerstone of the market for Renewable Energy Certificates is the knowledge that RECs have passed muster with independent verifiers like San Francisco-based Green-e. But now that a certified company has fallen out of compliance, Green-e is in the position of having to play hardball to maintain the market's credibility.