March 29, 2005

The Dirt on Carwashes

By Lorraine Sanders
Special to the Neighborhood Newswire

With their heavy water use and sudsy asphalt lots, commercial car washes may seem like environmentally un-friendly establishments. But fixed, for-profit car washes may result in better environmental outcomes than cleaning your car in your driveway or at a local community car wash fundraiser.

"What [commercial car washes] tend to do is they recycle their water, and the really dirty stuff that's left over is trucked off," explains Will Bruhns, senior engineer with the San Francisco Bay Regional Water Quality Control Board.

Both full-service washes, like Divisadero Touchless Carwash and Tower Car Wash, and self-service washes, which typically have multiple bays where owners pay to wash their vehicles, collect used water, preventing it from entering storm drains. Oil, chemicals and solids are extracted from the wastewater through onsite filters before being dumped into San Francisco's sewer system.

Carwashes, as well as any city businesses discharging more than 25,000 gallons of water per day, must meet city water quality standards before dumping wastewater into the sewer. The city tests wastewater for PH as well as grease, oil, dissolved sulfides and metals, and can fine businesses which exceed pollution limits.

The city randomly tests carwash discharge water four times annually during an establishment’s first two years of operation. If test results are consistent during this period, subsequent random monitoring occurs once a year. According to the San Francisco Public Utilities Commission, no city carwashes have violated San Francisco water standards within the last two years. The SFPUC was unable to provide information on violations that may have occurred before 2003.

In addition to potential pollution, carwashes also use large amounts of water. According to the Western Car Wash Association (WCA), an association of professional car wash operators, full-service car washes use about four times more water than self-serve establishments.

"You probably are only looking at anywhere from 40-45 gallons of water per car," says Sam Olivito, executive director of the WCA. "In a self-serve, you probably only use about eight to 10 gallons of water."

While self-service car washes use less water than their full-service counterparts, at self-service establishments water is typically only used once and sent through a single treatment step before heading into the sewer system.

In contrast, Olivito says full-service washes only use fresh water during the final rinse stage of the car wash. Recycled (also called reclaimed) water is used in other wash stages, such as pre-rinsing and undercarriage washing. In addition, full-service car washes employ between three and nine steps to clean wastewater, including filtering water through activated carbon, applying water softeners, and using ion exchanges.

While the sludge that collects in car wash cleaning systems ends up in landfills, Olivito claims it's not toxic. "There's a residue that's left. It's like a mud or silt that is dried and processed and taken to a sanitary landfill, and it's non-hazardous," says Olivito, who estimates car wash operators clean their water quality systems of solids about twice a year.

City officials say that the soaps and chemical cleaning products used at commercial car washes pose no more of an environmental threat than similar waste coming from businesses like laundromats and restaurants. Tyrone Jue, spokesperson for the San Francisco Public Utilities Commission, says San Francisco's sewer treatment program removes about 90 percent of the solid waste from water, which exceeds state and federal requirements. With a combined sewer system that funnels both storm and sewer water through the same treatment system, San Francisco sounds, at first, like a better place for residential car washing and car wash fundraisers than cities whose storm water and runoff from streets heads directly for local waterways. "Wastewater and drain water drain into the same pipes," Keith Silva, pretreatment coordinator for U.S. Environmental Protection Agency, Region 9, says of San Francisco's combined system. "The nice thing about it is that it all goes through a sewer before it goes out to the Bay."

But there are still problems. Most of the city's 25,000 storm drains are connected to the combined sewer system, but about 2,000 are not. When water enters unconnected drains, it flows directly into local waterways. Grease, oil, paint and solids that flow from cars contribute to pipe clogging, which, in turn, can cause sewer system back-ups and overflows.

There are simple ways to make residential washing less harmful to the environment. Products like Dri Wash n' Guard and No-Wet Waterless Carwash are spray-on car cleaners that claim to do just as good a job as a regular carwash, only without the water. Waterless wash products are applied to the car, and then buffed off with a terry cloth.

If you do choose to use water, washing on grass instead of in a driveway or on the street can reduce runoff water. Regular vehicle maintenance lessens oil and chemical residue leaks. And Lena Brook, associate director of San Francisco's Clean Water Action and Clean Water Fund, suggests using plant-based soaps whenever possible. "Most people are using unnecessarily harsh soaps that are also more environmentally dangerous or contaminating. You can wash your car with dishwashing soap," she says.