The car is clean but what about the water? Wash your car the right way


For many, car washing is a summertime ritual. Often, citizens don’t know that by washing all that grime off your vehicles they might actually be causing harm to our local waterways.

Water entering the storm drain, unlike water that enters sanitary sewers, does not undergo treatment before it is discharged into our waterways.  When cars are washed on streets and driveways, that dirty water eventually winds up in rivers, streams, creeks, and lakes.

Washing one car may not seem to be a problem, but collectively car washing activity adds up to big problems for our local lakes, creeks and streams.  Pollution associated with car washing degrades water quality while also finding its way into sediments, impacting aquatic habitats. 


Washing your car is only a problem if you don’t know where or how to do it correctly. The average homeowner uses 116 gallons of water to wash a car! Most commercial car washes use 60% less water for the entire process than a homeowner uses just to rinse the car. Among the many impacts of motor vehicles on our environment, car washing has been noted by water quality experts as a serious contributor to water pollution.

Water that runs off a car when it is washed in a driveway, street, or parking lot can contain substances that pollute the environment. Dirty water containing soap, detergents, residue from exhaust fumes, gasoline, heavy metals from rust, and motor oils can wash off cars and flow directly into storm drains and into the nearest creek or stream where it can harm water quality and wildlife. 

The phosphates from soap can cause excess algae to grow. Excessive algae smells bad, looks bad, and harms water quality. As algae decay, the process uses up oxygen in the water that fish need.

Car wash fundraisers can be a significant source of this kind of pollution. These events are usually held in heavily paved areas where there is little runoff control or grass to filter out harmful substances before they reach our waterways.


The best way to minimize the effect washing your car has on the environment is to use a commercial car wash. Most locations reuse wash water several times before sending it to a treatment plant. 

However, if you choose to wash your car at home or on the street, these are some things that you can do to minimize the water quality impact:

¨ Use biodegradable, phosphate-free, water-based cleaners only;

¨ Minimize water usage. Use a spray gun with flow restriction to minimize water volume and runoff;

¨ Wash your car on an area that absorbs water, such as gravel, or grass. This can filter water before it enters groundwater, storm drains, or creeks.  Avoid washing cars on concrete or asphalt pavement unless it drains into a vegetated area;

¨ Only let wash water soak into the ground if you are using biodegradable, phosphate-free cleaners;

¨ When planning a car wash fundraiser, try developing a partnership with a commercial car wash facility, or use a safe location; and,

¨ Always empty wash buckets into sinks or toilets.

Claire Posius is the Euclid Creek Watershed Coordinator.

Cuyahoga Soil and Water Conservation District, 216-524-6580,,

Read More on Naturally Collinwood
Volume 2, Issue 10, Posted 5:00 AM, 10.01.2010