WHERE DOES THE WATER GO AFTER YOUR CAR HAS BEEN WASHED?

Published: 04/18/2008

NOTE: This essay was written prior to the implementation of Phase II of The Clean Water Act. Phase II went into effect on December 8, 1999.

The public seems to have a misconception that washing a car at a full service car wash uses more water and creates more pollutants than washing a car at home. All the public sees is a large number of cars going through the carwash and the amount of water used. The general public is unaware of the sophisticated technology built into a full service carwash. Using a full service car wash rather than washing a car at home is less dangerous to the environment.

A full service car wash uses less water per vehicle than washing a car at home in the driveway. A study done by the International Carwash Association shows that an average car washed at home uses up to 140 gallons of water per car. The study was conducted using a typical 5/8" garden hose using 50 pounds per square inch (PSI), running on an average of 10 minutes.

Similar studies have been done by the New England Carwash Association based in Massachusetts, the Southwest Carwash Association based in Texas, and the Western Carwash Association based in California. All of the studies done by these different carwash associations came up with similar findings. These figures are now considered the industrys standard. These tests were conducted with the hose continually running during the carwash process.

Cars washed at a full service carwash use water at a much higher pressure with a lower volume. This is done by using high-pressure pumps and nozzles designed to wash a larger surface area in a shorter amount of time. This process washes each vehicle as quickly, yet effectively, using the least amount of water possible. Car wash operators realize that they must do all they can to conserve water since this is their biggest expense in operating a professional car wash.

The Clean Water Act of 1989 requires wastewater either to be piped to a municipal sewer plant or hauled off to a water treatment facility. Car wash operators are now continually looking for ways to decrease their fresh water usage, while still being able to supply the customer with a high quality car wash. One of the changes made by car wash owners include increasing the conveyor speed, which decreases the wash time. Another change made is they no longer let the spray nozzle run continually. Now, the nozzles are controlled by timers and some operators have gone a step further. They put in photo sensors, which now trigger the nozzles to spray only when it senses the front of the car and automatically shuts off when the vehicle has passed.

Opponents of these studies argue that most people who wash their cars at home do not leave the water running the duration of the carwash. Instead, they use a nozzle to control the water usage. Therefore, opponents believe they are not wasting water as claimed by the various carwash associations.

The New England Carwash Association wanted to investigate further this claim and, in doing so, they hired Lycott Environmental Research, Incorporated, an independent testing alb. One of the purposes of this study published April 28, 1988 was to compare the water usage of home Carwashing versus a professional carwash. Lycott's findings showed that using what they called a low flow, which is water turned off when water is not being actively used, drastically cut water usage. This method used 22-25 gallons of water per vehicle. The difference between home washing and a professional car wash is that water used at home is one-hundred percent fresh water that runs down the storm drains, taking with it all the pollutants directly to the ocean, rivers and streams. The water used in a professional car wash gets reclaimed and recycled prior to being sent to a water treatment facility.

The water used to wash a car in the driveway cannot be reclaimed or recycled. Professional car washes have a system designed to reclaim, filter and then reuse wash water. The water used during the car wash process is piped to underground holding tanks. This water is then reused as wash water after it has been filtered, removing suspended solids and free floating oil and grease. Suspended solids are fine particles of dirt and grit that are free floating in the middle of the tanks. After the dirt and sludge have settled to the bottom and the oils and grease float to the top, what is left in the middle is water with suspended solids. By using a three compartment settling tank, the suspended solids are given enough time to settle to the bottom. The filtered water is then pumped back into the car wash system to be used again as wash water. This process allows car wash operators to recycle and reuse the wash water, thereby reducing the amount of fresh water used.

Along with recycling and reclaiming the water, a car wash operator must use soaps and waxes specially formulated for use in car wash systems that use reclaimed water. The purpose of these products are to prevent spotting and to make sure that the soap rinses off with a minimal amount of water.

Steve Nayville from the Riverside County Regional Water Board stated in a phone interview on February 24, 1999 that he felt washing your car at home didn't waste a significantly large amount of water, nor did run off water have enough contaminates to pose a danger to the environment.

Run off water from a car washed at home is unregulated unlike a full service car wash, which must take the wastewater to a water treatment facility. When washing a car at home, the run off water flows freely down the driveway to the storm drains and goes directly to our oceans, lakes and streams. In an interview with Tari Patterson from the Department of Toxic Substance Control, Californias branch of the Environmental Protection Agency (EPA), stated that car wash owners must meet local discharge guidelines. Tari also said that her department doesn't regulate residential car washing, but instead monitors industrial discharges.

Since the Clean Water Act of 1989, professional car washes have been required to dispose of their wastewater and sludge at a water treatment facility. The only non-hazardous wastewater facility in Southern California built specifically for car wash waste is located in Los Angeles.

The company Southwest Treatment Systems gave me a guided tour of their facility and explained to me their process for treating car wash waste. While I was there, Jeff Jerome, the plant manager, explained to me that most of the pollutants in car wash waste are concentrated in the sludge. Mr. Jerome showed me a lab report done by Associated Laboratories, a state certified lab in the city of Orange. The lab report showed a break-down of the levels of metals in car wash sludge.

There are seventeen priority metals that the state of California regulates. This lab report showed high levels of chrome, copper, lead, nickel and zinc. Southwest Treatment is only permitted to receive non-hazardous waste with levels falling below California's hazardous limits. Although these results were considered high, they did fall below hazardous levels. For example, the zinc test showed a result of 1,038 parts per million. The hazardous limit is 5,000 parts per million.

Although this amount of zinc fell well below hazardous limits, it was substantially higher than the local discharge limits of 10 parts per million in water. This is why car wash owners must have their waste taken to a treatment facility and reduce the metals and suspended solids before discharging to a local sewer system. Los Angeles County Sanitation District employees then monitor Southwest Treatment's processed discharge water.

I showed Mr. Jerome copies of lab results from Ted Bert, owner of Deer Creak Car Wash. Mr. Bert used Western Analytical Laboratories, Inc. of Chino, California. These samples were taken from the last stage of the car wash clarifier. The result showed suspended solids and total dissolved solids ranging from 200-700 parts per million. I asked Mr. Jerome what the levels would be after treating this wastewater in his facility before being discharged into the sewer system. Mr. Jerome said that the typical results from this range would be 30-40 parts per million before entering the county sewer system.

Results from a monthly lab report on Southwest Treatment water showed that virtually no metals were detected after being processed. The lab report also showed a lack of volatile organic compounds (voc's), or as Mr. Jerome explained to me, "oils, greases, solvents or gasoline, which can be found in car wash waste."

The state of California, local county sanitation districts and regional water boards all seem to feel that washing cars at home pose no real great danger to the environment neither the amount of water used nor the pollutants generated are enough to warrant regulation.

One car washed at home really isn't enough to be alarmed about, or is it? After all, it's not just one car being washed at home. Thirty-nine percent of car owners wash their cars at home, which generates a substantial amount of water an pollutants going directly into our storm drains that eventually end up in our oceans and the environment.