San Francisco — An anti-meat “naked shower” protest from People for the Ethical Treatment of Animals at the corner of Powell and Geary Streets tomorrow will demonstrate that the animal rights group’s employees either aren’t terribly good at math, or don’t shower often enough.

PETA falsely claims that producing 1 pound of meat requires the water equivalent to more 6 months’ worth of showers. But according to the Council for Agricultural Science and Technology (CAST), it would take less than 18 ten-minute showers to consume the amount of water required to produce a pound of American beef.* That includes all the water consumed by cattle, plus everything involved in irrigating feed crops and processing the meat.

“If these PETA protesters are only showering 18 times every 6 months, I guess Union Square is as good a place as any to catch up,” said David Martosko, Director of Research at the Center for Consumer Freedom, a food-issues watchdog group. “The vegetarian fringe is always trying to create more converts, but the facts just aren’t on their side.”

“We’ve always thought PETA stinks, and now we know why,” Martosko concluded.

In April, PETA held a nearly identical protest in New York City’s Times Square, claiming on that occasion that the amount of water required to produce 1 pound of meat was equivalent to an entire year’s worth of showers. As is often the case with PETA’s campaigns, the numbers have shifted — but not nearly far enough.

*CAST calculated in its 1999 Animal Agriculture and Global Food Supply report that producing one pound of beef consumed a total of 435 gallons of water. Typical modern shower heads consume 2.5 gallons of water per minute; a 10-minute shower uses 25 gallons.