Officials are monitoring the Russian River after 97,000 gallons of wine leaked from a tank at the Rodney Strong Vineyards into the waters.
Cabernet sauvignon poured into a sewer system Wednesday afternoon, because a door to a blending tank popped open, a Rodney Strong spokesman told the Santa Rosa Press Democrat.
The wine spilled into a drainage ditch in Healdsburg that feeds into a creek, which ultimately flows into the Russian River.
The winery said it's conducting an investigation and cooperating with authorities.