Frequently Asked Questions


No, we are an independent special district governed by an eleven member Board of Trustees.
Each of the seven cities in San Joaquin County appoint one trustee and the San Joaquin County Board of Supervisors appoints four trustees to represent the unincorporated areas of the county.

The District is funded through ad valorem (property) taxes and special benefit assessments.

Mosquito and vector control is an integral part of public health.The District’s program provides comprehensive vector surveillance and control services to protect the public’s health by reducing the transmission of diseases and maintaining quality of life.

Yes, the District offers presentations to civic groups, safety group meetings, and other adult groups of 15 or more people. We also offer presentations to high school agricultural / FFA classes and biology classes.  Elementary school presentations are offered to 5th and 6th grade classes.  The presentations are free.  Please call the Public Information Officer, Aaron Devencenzi at (209) 982-4675 to schedule an appointment

San Joaquin County Mosquito & Vector Control District Logo
District Logo

All of our technician will be in a green and tan uniform with the District logo and ID badge.  Each technician will have a vehicle with the District logo on the doors. If there is any question or concern, call the District at (209) 982-4675.



The mosquito development is dependent on weather conditions. The warmer the weather, the faster the mosquitoes can develop. In spring, summer and fall mosquitoes can develop in 3 to 10 days depending on the species.

Mosquitoes develop in standing water. Remove water from buckets, and any other water holding receptacles around your home. Don’t over water. Water standing for more than four days can harbor mosquito development. Clean your rain gutters at least twice a year or more to avoid plugged downspout and standing water.  Clean bird bath out once a week. Be sure to keep pool filtering equipment and necessary chemicals in swimming pools. It is also important to fix broken sprinklers and leaking faucets. Stock mosquitofish in animal troughs, ponds and water features when necessary.  Call the District if you need additional help.

Yes. As weather warms, a few mosquitoes are normal, however many mosquitoes can be a problem. Because we are local government, there is no charge for District services when we respond to a service request.  Please call (209) 982-4675 or 1-800-300-4675, or file a request online under the “Request Service” tab on this website.

The date, your name, address of property to be inspected, as well as, a daytime telephone number for follow-up calls. For our protection, we would also like to know if there are any dogs and if they bite. If you want to be present during the inspection, please call us between 7:00 to 3:30 to make an appointment.

In the comments section please state the nature of the problem.For example, mosquitoes biting in the evening or during the day;mosquitoes are in the house; mosquitoes are not biting but cover my window screens, etc.

If you can catch a couple of mosquitoes and place it in a plastic bag(dead or alive) it will help the service technician to determine the type of mosquito and its habitat.

Yes, we still need your first name and contact number for follow-up questions.  Please state in the comments section that you would like to remain anonymous.


Swimming Pools

  1. The District will make several attempts to contact the owner of record.
  2. If access is denied, the District will obtain a search warrant and enter the property accompanied by law enforcement.
  3. Upon entry, the District will give the owner the opportunity to clean the pool or drain it depending on local ordinance.
  4. If the owner opts to clean or drain the pool, we will recheck the pool in a few days to verify its condition.
  5. If the owner opts for us to treat for mosquitoes, we chemically treat the pool and return in a few days to place mosquito eating fish in the pool. 

The mosquito control technician checks for mosquito development. If there is mosquito development, mosquito fish and chemical control methods are used to stop development. Our service does not change the color of the pool.  A professional pool cleaning company needs to be contacted to bring the pool back to working condition.

No. Contact a professional pool service.

The District needs a physical address.  For follow-up calls, a first name and contact number is also important. Additional information is helpful.  Is the home occupied, are there dogs, is the property for sale etc.

The pool can be professionally cleaned and brought back to routine service.  The District does not want bleach or chlorine dumped in the pool for a short term clearing; this practice kills the mosquito eating fish and will eventually cause mosquito problems in the neighborhood.

If you can catch the fish and place them in a bucket, the District will pick them up. The District does not remove the mosquitofish from the pool.



If you reside in San Joaquin County or cities with in the County,call the District office and when available, the fish can be delivered or picked up at the District office: 7759 S. Airport Way, Stockton CA. 95206.

Because our services are paid for through taxes and benefit assessment of San Joaquin County property owners, only those who reside in San Joaquin County receive our services. Contact your county government for information on what service your county provides.

See the attached link for additional mosquitofish information: Mosquitofish

Mosquitofish can be aggressive to other fish, causing stress.Although our mosquitofish are treated for parasites, there is still a risk of parasites and other diseases transmitted to your Koi. For these reasons, the District does not recommend mixing Koi with other fish. It is up to the owner’s discretion to take the risk.  The District is not responsible for loss of other fish.


Bees and Other Insects

The District can offer information for these insects as well as insect identification. For control of these insects, the owner needs to call a private pest control company.


West Nile Virus



Often this term is used loosely by the public.  The District treats for mosquito development in aquatic sources on a routine basis, year round. Sometimes the sites are sprayed with a liquid formulation; others are treated with granules, tablets or other forms of larviciding products.

When we treat for adult mosquitoes, the District may use barrieror surface sprays from a hand can, or truck mounted sprayer. When it is necessary to cover large areas, trucks or airplanes use an Ultra Low Volume Sprayer (ULV) emitting a fine mist when mosquitoes are most active, usually at dusk or dawn. The mist kills mosquitoes on contact.

If West Nile virus is detected in the community, the District’s response will be to concentrate additional efforts to treat for immature mosquitoes (larvae) found in aquatic sources.Reducing the adult mosquito populations with pesticides(adulticides) registered by the US Environmental Protection Agency(EPA) will be done if necessary to prevent human illness or to suppress a heavy infestation of mosquitoes. The decision to spray,either by truck mounted sprayers or by aircraft, will be based on surveillance information and/or the documentation of West Nile virus activity at a level that indicates a threat to human health. Spraying will be concentrated in areas most at risk for disease occurrence and will be conducted by certified and licensed applicators.  The District’s aggressive campaign against larvae is intended to minimize the need for spraying adult mosquitoes.

The District sprays for adult mosquitoes when adult mosquitoes are present. If you are having a mosquito problem, it helps to have a few collected for identification. Often we can find the source of mosquito development based on the mosquito species. We do not spray when mosquitoes are not present.  

The District makes no recommendations on necessary precaution other than using common sense. However, people can take extra precautions if it makes them feel more comfortable. Please call the District if you have additional questions.

The District issues news release and spray alerts for adult mosquito control in public areas. This information can be found on this website under “News & Spray Alerts” or by calling the District office during working hours at (209) 982-4675, from 7:00 a.m. to 3:30 p.m.  The District also offers email notification through GovDelivery found on the home page and several other areas of this website. We are not responsible for notification or its accuracy that is printed by newspapers or reported on television.