Car Washing

The gutters along our city streets lead to storm drains that flow directly to local creeks.  People caring for their vehicles can unknowingly impact local waterways when washing vehicles with any water. Wash water has the potential to transport materials attached to the vehicle such as soap, metal shavings from brake dust and rotors, vehicle fluids (engine oil, antifreeze, transmission fluid), and road contaminants to the storm drain. These can be harmful to water quality and creek habitats. 

Products labeled “nontoxic” and “biodegradable” can still harm wildlife if they enter the storm drain system. These products are prohibited discharges to the storm drain system.

How are the Storm Drain and Sanitary Sewer Systems Different?

The storm drain system transports rainwater to local creeks, rivers, and the ocean. This system was created to prevent flooding within communities and homes.

All water and materials that enter the storm drain system are untreated.

The sanitary sewer is a plumbed system that transports used water from buildings to a wastewater collection and treatment facility, where the water and sewage is treated.

If you see an outdoor drain and are unsure of its use, assume it is a storm drain and do not discharge wash water to it.

Clean creeks are important. They provide vital fish habitat, recreation, and add to the beauty of our city.

The preferred way to wash vehicles is at a professional car washing facility where water is recycled or sent to the sanitary sewer system, however, individual residential car washing is permissible by city code when properly managed.

If you wash at home, and have considered alternative discharge methods, such as discharging to the sewer, and those are not possible, the following practices are recommended:

  • Wash in an area where the water can infiltrate the ground, such as a vegetated or landscaped area (such as a lawn or permeable pavers).
  • Pumps, vacuums, or physical routing may be used to direct runoff to the sewer, landscape, or other areas for infiltration or re-use.
  • Practices that minimize runoff, such as using a bucket and sponge to contain fluids should be implemented.

Parking vehicles on a flat, permeable surface like your lawn, gravel, or dirt, rather than on pavement allows natural microbes in grass, soil, and dirt to work as natural filters, breaking down some of the harmful compounds found in wash water and preventing them from running off into the nearest storm drain. 

Washing Your Vehicle on the Lawn

  • Use this method if your lawn is accessible and sufficiently sized.
  • Use minimal water and soap to reduce the pollutant load.
  • The lawn will allow the rinse water to soak into the dirt where soap can break down into less harmful pollutants.

Creating Your Own Berm

Gather up a few simple items from around your home to make your own berm to divert or contain wash water. To start, grab a towel (preferably a beach towel) and a plastic garbage bag.

  1. First roll the towel up tightly. The optimum way to do this is to start in one corner of the towel and roll towards the opposite corner of the other side of the towel.
  2. Once you have the towel rolled and tight, fill an empty bucket with water and completely soak the towel.
  3. Take the wet towel and place it into a plastic garbage bag. Tie a knot on the open end of the plastic bag to seal.
  4. Place your berm on a flat surface to divert or pool water accordingly.
  5. Once in place, step on top of the bag and towel to flatten. Press the bag and towel firmly against a flat service to increase surface area and to help create a seal.
  6. Your berm is ready to go. (Remember, one gallon of water weighs 8.35 pounds. When placing your berm to pool water, such as placing in a gutter, use a heavy object from around the home, like a garbage can, to secure the backside of the towel from the weight of the pooling water.)
  7. Rinse water can be redirected to landscaping using this berm or you can purchase a relatively inexpensive hand siphon pump, typically under $10, to pump any pooled water into a bucket where it can be disposed of in a nearby sink or toilet or into nearby landscaping.

Washing Your Vehicle on the Street

  • Use two buckets of water, one for soapy water and one for rinse water.
  • Make sure your sponge is damp, but not sopping wet, to reduce drips onto the pavement.
  • Start by wiping down the car with the soapy water.
  • Next, wipe down the car with rinse water.
  • Dump both buckets into the sanitary sewer through a sink or toilet.
  • Another option is to block the street gutter with plastic bags filled with dirt (like a sandbag) allowing the rinse water to pond up. Collect the water for disposal to the sanitary sewer. Rinse the area and capture the rinse water to ensure all the soap and other pollutants are collected for disposal to the sanitary sewer.

Report Spills Here

Cloverdale: (707) 894-2150
Cotati: (707) 665-3605
Healdsburg: (707) 431-7000
Rohnert Park: (707) 588-3300
Santa Rosa: (707) 543-3800,
After Hours: (707) 543-3805
Sebastopol: (707) 823-5331,
After Hours: (707) 829-4400
Ukiah: (707) 463-6288
Unincorporated County of Sonoma: (707) 565-1900
Unincorporated Mendocino County: (707) 234-6679
Windsor: (707) 838-1006,
After Hours: (707) 838-1000

It is illegal to allow anything other than rainwater to be discharged to a gutter or storm drain.