Stormwater FAQs

Through on-going contacts with the public, Stormwater Management Program Staff receives many questions regarding stormwater pollution, as well as on the County's Stormwater Program in general.  The following are some of the most frequently asked questions:

A catch basin or storm drain is a curbside drain with the sole function of collecting rainwater from our properties and streets and sending it to local waterways. Storm drains are also found in parking lots and serve the same purpose. In county and city areas, stormwater never goes to a sewer treatment plant to be cleaned, but flows directly into our creeks, sloughs, and rivers.

In San Joaquin County, sewers and storm drains are two completely different drainage systems. Sewers carry wastewater from such things as washing machines, sinks, toilets, and showers to a treatment plant to be cleaned prior to being discharged into the San Joaquin River. The storm drain system collects rainwater, and anything else dumped into it, and carries it all directly to our local waterways without any treatment.

In most areas, the San Joaquin County Public Works Utilities Maintenance maintains both the sewer system and the storm drain system. Sanitary sewers in urbanized areas of Stockton may be maintained by City of Stockton or Country Club Sanitary District.

Yes. The County regularly performs maintenance activities which includes cleaning the storm drain system. In addition, the County crews are always available to respond to emergency situations where clogged drains result from flooding.

County crews clean out clogged catch basins throughout the year as part of on-going maintenance. Unfortunately, there are many catch basins and not enough resources. Residents can reduce flooding in their neighborhoods by keeping materials out of the storm drain system or clean debris around a catch basin when performing landscape maintenance.

It sounds like a good idea, but during a rainstorm, debris (e.g. leaves, sticks, trash) is quickly swept to the catch basin and any screen or filtration device placed in front of the catch basin would clog the grate, resulting in flooding.

Unfortunately, nets only catch larger pieces of the trash — all of the pollutants like pet waste, used oil, pesticides, fertilizers, etc., flow through the net and straight into our waterways.

Such a facility would be extremely expensive to build and maintain, and these costs would need to be passed on to property owners.

Paint thinner and paint products, motor oil, pesticides, trash, paper, human and animal feces, antifreeze, leaves, grass clippings, cooking oil, shopping carts, tires, dirty diapers, and dead animals are but a few of the pollutants found in the system.

The storm drain system is built as the land is developed. This is done to insure that as new development occurs, proper drainage is provided.

The County will investigate all reports of illegal dumping into the storm drain system. To report dumping, please call the hotline at 1-866-755-4955. Each call is treated with confidentiality.



Anyone caught dumping can be cited and fined. The guilty party may also be responsible for cleaning up the material and the storm drain system.

Dumping used oil is illegal. One quart of motor oil can pollute 250,000 gallons of drinking water. To report the problem, call the hotline at 1-866-755-4955.

Used oil should be taken to a nearby gas station or auto parts dealer that accepts used oil. Not only will used motor oil be kept out the stormwater system, the oil will be processed and used again as re-refined oil. In addition, anyone bringing used motor oil to a recycling center will be paid a refund. To find the nearest dealer who will accept used oil, contact the San Joaquin County Solid Waste Division at 1-800-449-4840.

The storm drain system is for the sole purpose of collecting rainwater overflow. Dumping trash, pollutants and debris in the catch basins is illegal and is a federal violation of the Clean Water Act of 1972, as well as San Joaquin County Ordinance. A neighbor may not understand that the catch basin directly connects to the San Joaquin River and other waterways. It may be just a matter of making them aware of its environmental impact. County staff would be more than happy to provide information to your neighbor by contacting us at 1-866-755-4955.

Contact Household Hazardous Waste facility at 1-877-747-9699 for available dates and times.

One option is to have vehicles cleaned at a commercial car wash where wastewater flows through sand and oil traps them into the sanitary sewer system. When washing your car at home, pull it up on the lawn or graveled area where water will leach into the ground instead of flowing into the gutter and storm drains. Always use biodegradable soaps when washing a vehicle and conserve as much water as possible. Shut off water while washing your car, then rinse. Remember not to leave your car on the lawn. We would highly recommend going to a full or self-service car wash because the water used is recycled.

Wrong. Grass, leaves and yard clippings that are repeatedly swept into catch basins can clog the drain, causing flooding and becoming a potential breeding ground for rodents and insects. Additionally, when this material reaches our waterways, it decomposes and robs the surrounding water of oxygen that is needed for aquatic life.

Yes. The fine will vary depending on which local or state agency assesses the fine.

The community outreach efforts of the Stormwater Pollution Prevention Program consist of three main areas:

Industrial/Commercial: Educate facility and business owners/operators about stormwater regulations and how stormwater pollution can be minimized.

Construction: Provide outreach to the construction community about proper BMP implementation and compliance with County requirements and all applicable Permit conditions.

Residential/Community: Through education and outreach opportunities, promote change in behavior and encourage communities to reduce pollutants to the storm drain systems.

Community Education presentations raise awareness of our role and the impact to the watershed all around us. We focus on storm water pollution prevention with students in both public and private schools. The 45-minute program includes a short video, an overview of the water cycle, information on water conservation and a discussion on how students can help their families reduce stormwater pollution. Each student receives an activity booklet to reinforce the stormwater message while having fun.

At the high school level, the City of Stockton and San Joaquin County have partnered for stream clean-up projects. In the classroom, students are instructed on the importance of water. The students then take the lessons out into the natural environment and a nearby waterway to learn more about unnatural objects in the water, how it got there and its effect on the ecosystem. You may also contact the County for more information about the annual environmental video contest, where students are encouraged to write essays, create slogans, posters, and film short videos as part of their expanded knowledge of the importance of water.

The program culminates in a four-hour weekend stream clean up that coincides with California Coastal Cleanup Day in September, to rid waterways of trash and educate the public about proper disposal of items such as tires and shopping carts. The City, County and other partnering agencies provide the supplies for the clean-up effort, our citizens provide the support. California Coastal Cleanup takes place annually and attendance is open to the public. Walk-ons are welcome!

To view the Stormwater FAQs document, click hereOpens in new window.