Hertz and Enterprise, two of the world’s largest car rental companies, have tried to win the hearts of environmentalists by renting out electric vehicles.

Now both companies are going even greener by launching car-washing systems that use less water to keep rentals looking new.

Hertz has begun to use a biodegradable spray solution wiped off with microfiber towels at 220 locations across the country. Next year, Hertz hopes to expand the program to all 3,700 locations in the U.S. and Europe, saving more than 130 million gallons of water annually.

Not to be outdone, Enterprise is expanding to its rental outlets in Hawaii and California a non-toxic washing system that is now used only in certain New York and Boston locations.

The system uses a highly concentrated cleaning solution that is also sprayed on the cars, reducing its carbon footprint by 95 percent, compared with traditional car-washing methods, according to the manufacturer.