The suits, filed in Pennsylvania, California and other states, claim consumers have been cheated out of the alcohol content stated on labels. Budweiser and Michelob each boast of being 5 percent alcohol, while some "light" versions are said to be just over 4 percent, reports CBS News.
The lawsuits are based on information from former employees at the company's 13 U.S. breweries, some in high-level plant positions, according to lead lawyer Josh Boxer of San Rafael, California.
The excess water is added just before bottling and cuts the stated alcohol content by 3% to 8%, he said.
Anheuser-Busch InBev called the claims "groundless" and said its beers fully comply with labeling laws.
The suit involves 10 Anheuser-Busch products: Budweiser, Bud Ice, Bud Light Platinum, Michelob, Michelob Ultra, Hurricane High Gravity Lager, King Cobra, Busch Ice, Natural Ice and Bud Light Lime.
Anheuser-Busch, based in St. Louis, Missouri, merged with InBev in 2008 to form the world's largest alcohol producer, headquartered in Belgium. In 2011, the company produced 22 billion gallons of alcoholic beverages, 3 billion of them in the U.S., and reported 22 billion dollars in profits, the lawsuit said.
According to the lawsuit, the company has sophisticated equipment that measures the alcohol content throughout the brewing process and is accurate to within one-hundredth of a percent. But after the merger, the company increasingly chose to dilute its popular brands of beer, the lawsuit alleged.