San Joaquin River

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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:

Q: What is a catch basin or storm drain?
A: 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, via underground pipes. 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.  

Q: Are sewers and storm drains the same things?
A: 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.  

Q: Who maintains the County's storm drain system?
A: 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.  

Q: Do catch basins and storm drains get cleaned out?
A: 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.  

Q: Why doesn't the County clean out all of the storm drains before a storm?
A: 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.  

Q: Why doesn't the County install filters or screens in front of catch basins?
A: 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.  

Q: Why isn't a net/fence/barrier installed at the end of the storm drain channel to catch all of the trash?
A: 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.

Q: Why doesn't the County build a stormwater treatment facility?
A: Such a facility would be extremely expensive to build and maintain, and these costs would need to be passed on to property owners.  

Q: What kinds of pollutants are found in the storm drain system?
A: 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.  

Q: When was the storm system built? Why?
A: 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.
Q: What is the County of San Joaquin doing about illegal dumping?
A: 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.  

Q: I see people dumping their used oil into storm drains all the time.  What can I do?
A: 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


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.
Q: What should I do if I see a neighbor throwing trash into a storm drain?
A: 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.
Q: How can I properly dispose of left-over paints, thinners, chemicals, car batteries, etc.?
Contact Household Hazardous Waste facility at  877-747-9699 for available dates and times.


Q: I wash my own car. How can I be environmentally responsible?
A: 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.  

Q: Yard clippings and leaves are natural, so they don't cause any problems, right?
A: 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.  


Q: Is there a fine/penalty for illegal dumping?
A: Yes.  The fine will vary depending on which local or state agency assesses the fine.  


Q: What kinds of educational programs or informational materials does the County offer for students?
A: 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 to our role and impacts 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.  There is no charge to the class for the program. Churches, and Citizen Groups are also welcome to contact us.

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 welcome. Or call ahead with a group.

For more information on these and other outreach programs, please contact the Stormwater Management Program at (209) 468-3055.

Q: I have often seen stencils over the catch basins.  How do I get a stencil for a catch basin near me?
A: The storm drain stencils are part of the outreach efforts of the Stormwater Management Program.  Local youth groups, civic organizations, school clubs, and other interested groups are welcome to take part in this community service effort.  Materials will be provided for the project by the County.  The County will work with the group in deciding locations for the stenciling project. 

For more information on these and other outreach programs, please contact the Stormwater Management Program at (209) 468-3055, or e-mail



PO Box 1810 / 1810 East Hazelton Avenue, Stockton, California 95201    |    Phone  (209)  468 - 3055

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The Stormwater Pollution Prevention Program is a Program of the

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