Old-school cooling systems on the roofs of larger Los Angeles buildings may be wasting billions of gallons of water each year.

The Los Angeles Times reported Saturday (http://tinyurl.com/zarkqn9) that some of these “swamp coolers” are so inefficient they can use as much water as all the bathrooms, drinking fountains and kitchens in the buildings below.

As California’s drought persists, officials are looking to supplement savings already won when property owners ripped out lawns or installed water-miserly appliances.