Dropzone Newsletter

By: Imbrium Systems

Nearly everybody remembers the very first car they owned. The reasons vary. For some it was a rite of passage into adulthood, the first real taste of independence from Mom and Dad. Perhaps it was the coveted reward of much hard work at a minimum-wage job and scrupulous saving, and being able to proudly say “I bought it, it’s mine!” It may have produced the liberating thought “I never have to beg a ride again!” Maybe it is recall of hosting your first tailgating party. For us older menfolk, it may conjure up memories of being able to impress our crush with a date to a drive-in movie (I miss those days…). And for most all of us, it was the most beautiful machine on four wheels we had ever seen…. whether a brand new high-revving sports car, a used economy model, a dented pickup truck, a clunker station wagon (that was the SUV of my youth), or anything in between. But what is the single most undisputed memory in common about “first car” ownership? Easy….the near-universal compulsion to give our most prized possession a regular bath!

Ah, yes, washing the car, making it shine! In their enthusiasm to keep the baby clean and spotless, the last thing that car owners may have on their minds is “Hey, I wonder where all that soapy water goes as it runs down the driveway and street?” Unfortunately, the answer is rather unsettling. In most urban areas, soapy water from car washing that makes its way onto a street or curb eventually enters the nearest downstream storm sewer. Once in the storm sewer, the destination is pretty much guaranteed: untreated discharge into a river, lake, or bay. That dirty, turbid, soapy water is a source of water pollution that is harmful to aquatic life.

Several of the constituents of car wash water can be detrimental to various living species in natural water bodies. Detergents often contain phosphates, which serve as nutrients for various forms of algae. Algae blooms are undesirable for several reasons. Some algal species produce toxic compounds that are harmful to fish, birds, and mammals. Decaying algae can deplete oxygen in the water and change water chemistry such that native species struggle or perish. Algae blooms also are unsightly and can produce foul odors and taste in the water. Oil and grease removed from vehicles, driveways, and streets by soapy wash water may contain various hydrocarbons that are toxic to aquatic life. And dirt and turbidity in the wash water can block light transmission in the natural water body, interfering with photosynthesis, and can also blind the gills of fish species.

So, does all this mean that we shouldn’t wash our cars? No, but it does mean that we should thoughtfully consider better locations for car washing. The two worst places to wash your car are on an impervious driveway that drains directly to a street curb or on the street itself. Dirty, soapy wash water runs directly off those surfaces and into the nearby storm sewer. A better choice is to wash your on a grassy lawn or over a gravel surface, using a phosphate-free detergent. These surfaces allow the wash water to infiltrate into the ground and naturally filter out particulate pollutants. Microbial species in the soil will gradually degrade the soap, detergents, oil, and grease. The best choice is to use a commercial car washing facility that has a water treatment process onsite and that recycles the wash and rinse water. This not only conserves water, but ensures that no water is discharged untreated.

While the best car washing option may be disappointing to those of us who relish the thought of a sunny Saturday morning with wet sponge in hand, the bright side is that a trip to the river, lake, or ocean that same sunny day will be more enjoyable knowing that we have done our part to help ensure a healthy ecosystem!

Read more in this series:

Part 1: Doo-Doo No-No

Part 3: Taking Out the Trash

Posted in: 2016, January 2016