This New York Times advice doesn't wash

The New York Times recently fell into a trap set by the commercial car wash industry. It is a trap that has ensnared many lesser publications, but you expect the NYT to be more careful.

In an article titled "One Thing You Can Do: Opt for the Carwash," the Times said that commercial car washes are kinder to the environment than a home car wash because they use less water. The story says that a driveway car wash "can quickly rack up 100 gallons of water or more." Commercial car washes, the article assures us, use less.

And what is the source of the numbers used in this comparison? Um, it's the commercial car wash industry itself, hardly an unbiased party in this debate. Yet the Times uses the industry's numbers without even a hint of skepticism.

The fact is that the 100 gallons figure is just flat wrong, and the Times could have easily found that out with a tiny bit of research, as I told the story's author, Jillian Mock, in an email:

Dear Ms. Mock:

I wish you had run your article by the New York Times' fact checkers before publication. The notion that home car washes use 100+ gallons is a long-discredited myth perpetuated by the commercial car wash industry. 

Way back in 2012, for example, Politifact put the idea to the test and found it took a mere 11 gallons to wash a car at home. 

You can easily test this yourself, as I did one day with my and my wife's cars.

First, I determined my hose's flow rate by timing how long it took to fill a one-gallon milk jug. Time: 7.37 seconds.

Then I measured how much water it took to fill the bucket. Total: 2 gallons.

The final step was to time how long it took to pre-rinse and post-rinse each car. Then add up the total number of seconds and divide by 7.37. Since my wife and I have two cars, I was able to basically run the experiment twice. Here are the results:

	Pre-rinse (seconds)	Post-rinse (seconds)	Total rinse time	Gallons (total rinse time/7.37)	Add 2 gallons used for bucket	Total gallons used
Toyota	41	48	89	12.08	2	14.08
Hyundai	47	41	88	11.94	2	13.94

As you can see, each car wash used about 14 gallons total, not even close to the 110 gallons mentioned in your story. (To be clear, it's best to take a moment before starting to think about how to rinse your car all the way around without backtracking. If you spray back and forth covering the same parts of the car more than once, you will obviously use more water. Still, you would have to be extremely careless to hit the 100-gallon mark.)

As far as runoff, there are ways to limit, or even eliminate, this at home. First, you can use biodegradable, non-phosphate car wash soap. You also can do as some of my neighbors' do - wash the car on the front lawn. Not only does this prevent runoff, it has the bonus effect of allowing the overspray of water to help irrigate your lawn. 

My wife and I can't do this because we long ago replaced our lawn with low-water-use plants. So when I wash our cars, I put down an old rolled up sheet to redirect any runoff (there isn't much since we're conscious of our use). The extra water flows onto a patch of grass by the curb. 

So while commercial car washes may claim to send contaminant-laden water to treatment facilities, smart home washers prevent those contaminants from entering the water system in the first place.

One last thing: Simply by choosing to stay home and not to drive to the car wash, you're lowering your carbon footprint. 

The unfortunate conclusion from all this is that the New York Times gave readers precisely the wrong advice. If you want to be kind to the environment, stay away from the commercial car wash and instead wash your car thoughfully at home.