◈ Homepage — https://www.contracostamosquito.com/Skip to main content Request Services Search: Search Home I Want To District Transparency Publications News/Current Topics Animal and Agency Resources Mosquito Control West Nile Activity Environmental Pools & Spas Stop Carousel Protecting Public Health Since 1927 ABOUT US REQUEST SERVICES FOR NEWS MEDIA FREQUENTLY ASKED QUESTIONS District Services and Programs READ MORE » 2026 West Nile Virus Activity A map that details mosquitoes, dead birds, chickens, and horses that have tested positive for West Nile virus. You can zoom in and out of the map and click on the place-markers to get a detailed… READ MORE » Invasive Mosquito Species Para ver esta página en español haga clic aquí READ MORE » One Mosquito Bite Can Change a Life Forever One mosquito. One bite. That's all it takes to change someone's life forever. The threat of mosquito-borne diseases like West Nile virus and Eastern Equine Encephalitis has risen in recent years and the effects on human life can be devastating. READ MORE » RFP/Qs There are currently no openings. Click here for a list of previous RFP/Qs. READ MORE » District Receives Leadership in Sustainability Award We are proud to share that the District was awarded the   Leadership in Sustainability Award from Sustainable Contra Costa. The honor was presented during a ceremony at the Pleasant Hill  Community… READ MORE » Board Meetings Most Recent Agenda Meetings MAY 18 2026 Personnel Committee Meeting Agenda COPYRIGHT © 2026 CONTRA COSTA MOSQUITO AND VECTOR CONTROL DISTRICT 5750 IMHOFF DRIVE, SUITE I, CONCORD CA 94520 TELEPHONE (925) 685-9301 PRIVACY POLICY DISTRICT TRANSPARENCY WEBSITE ACCESSIBILITY STATEMENT POWERED BY STREAMLINE | ◈ Interior Pages — 1 pages crawledServices and Programs - Contra Costa Mosquito And Vector Control District Skip to main content Request Services Search: Search Toggle navigation Home I Want To Request a District Service Report Mosquitoes Report an Unmaintained Pool Request a Mosquitofish Service Report a Dead Bird Request a Presentation/Event Participation Apply for a Job Subscribe to a District Publication Submit Public Records Request Learn About West Nile Virus Learn About Invasive Mosquitoes Contact the District District About Us Services & Programs Frequently Asked Questions Staff Board of Trustees Board Meetings Board Meetings Board Committee Meetings Transparency Publications Annual Reports Brochures Mosquito Bytes Newsletter News/Current Topics For News Media Invasive Mosquito Species Animal and Agency Resources Mosquito Control How the District Controls Mosquitoes Current Control Activities Frequently Asked Questions 2025 Control History West Nile Activity California 2026 Contra Costa Activity Archived West Nile Virus Activity Environmental Integrated Vector Management/Pesticide List Mosquito Reduction/Best Management Practices NPDES Documents Programmatic Environmental Impact Report Pools & Spas District Policy Draining Pools & Spas Report a Neglected Pool District About Us Services & Programs Frequently Asked Questions Staff Board of Trustees Board Meetings Services and Programs District services and programs for Contra Costa County residents are funded by your tax dollars and are provided at no additional cost. Our services and programs include: A technician conducts a residential mosquito inspection. Mosquitoes Our county’s diverse ecological regions create a range of mosquito sources. The District regularly surveys more than 10,000 acres of marshland along the waterfront, acres of irrigated farmland in the eastern county, and numerous ponds, creeks, and residential sources countywide in an effort to control the species of mosquitoes currently in existence while also on the lookout for the potential arrival of new and invasive mosquito species . The county is also home to many insects that resemble mosquitoes. A technician inspects an unmaintained swimming pool. Upon receiving a request for service , the District will check your property for mosquito problems and provide advice on controlling their populations. This may include the placement of Mosquitofish. Swimming Pools and Spas The District also appreciates Contra Costa County residents doing their part to protect public health by reporting unmaintained swimming pools (pools that are not chlorinated or filtered). Residents can submit swimming pool reports anonymously by phone (925) 685-9301 or online. Not only are they unsightly, but unmaintained pools and spas can pose a threat to public health. Mosquitoes need very little standing water to complete their life cycle. Swimming pools and spas that are not maintained can be an ideal source for more than 1 million mosquitoes that may go on to become infected with West Nile virus. These mosquitoes may affect people up to five miles away. While having a green swimming pool is not illegal, it is illegal to produce mosquitoes. A technician inspects for rats and mice. Rats and Mice Contra Costa County residents can request a site visit to assist them with issues by calling the District or making an online service request. Service consists of an exterior inspection of a residential property and advice. District employees do not bait nor set traps, but provide valuable, detailed information, guidance, and recommendations. A resident must call for an inspection of their own property. A technician inspects for evidence of skunks. Skunks The District's program to reduce the likelihood that humans come into contact with skunks is designed to reduce the risk of rabies, because skunks can carry rabies. A state-certified District technician will conduct property assessments to identify signs of skunk habitation on residential properties. Based on the inspection, residents will receive expert guidance on implementing effective deterrents and exclusion techniques to prevent skunk activity and interaction with people. To request a skunk inspection, call 925-771-6186 or request service online. Ground-Nesting Yellowjackets A technician confirms the location of a yellowjacket ground nest. Yellowjackets are beneficial insects that eat garden pests and pollinate crops through daily foraging; however, they are also considered a vector since they can cause people discomfort or be dangerous to individuals who are allergic to their venom. The District provides inspection and treatment of ground-nesting yellowjackets since these species are aggressive toward people. We do not provide a service for other species of yellowjackets, nor those that make their nest on or in structures. For ground-nesting yellowjackets, simply locate the nest and call us for service or make an online service request . If the nest’s location is known, please share that information with District employees. This can be achieved by pointing a garden tool in the direction of the nest or identifying the site with a marker (brightly colored sock, garden glove, etc.). If you could draw a simple map and affix it to the front door of the residence, we would appreciate that, as it would also help us locate the nest. Once you have requested District service, do not attempt to do anything to the nest. The nest must be dry and untreated for the District to treat it. Ticks and Lyme Disease The District provides identification of ticks and biting or stinging pest samples submitted by Contra Costa County residents. Residents may send a tick or pest sample to the District. The District does not test ticks for Lyme disease that are brought in by the public. Lyme disease testing is conducted for surveillance purposes only. A list of local laboratories that will conduct Lyme disease testing on ticks can be found by clicking here. Bees All honey bees are beneficial insects that are essential for the pollination of many native California crops and plants. If a bee swarm does not present an immediate threat, it is best to leave it alone. The vast majority of bee swarms in Contra Costa County are ordinary European honey bees in pursuit of a permanent home and are docile unless provoked. Both European and Africanized honey bees are non-aggressive in this stage as they are not protecting their honey or their hive. The swarms typically move away in a day or two. Do not kill, swat, or threaten the bees because that may cause them to release a pheromone that incites other bees to become aggressive to protect their colony. District services for bees are minimal. The District does not respond to bee-stinging incidents. In the case of a bee stinging incident that requires emergency services, please call 911 for assistance. We treat bee swarms or hives that are a threat to people in public areas such as a school or shopping centers. The District does not treat bee hives that are in or on a structure or on private property. The District does not determine if bees are Africanized or European. For help with bee swarm collection/removal, please visit the Mount Diablo Beekeeper’s Association online or contact a colony removal specialist or a private pest control company. Biting/Stinging Insect Identification Our public health agency provides an identification service for ticks, mosquitoes, and other stinging/biting pests only. The resident can bring a sample to the District office to request identification, or mail a sample to the District by placing it in a sealed zipper baggie or other sealed container, placing it in an envelope, and providing full contact information including an email address or phone number. In most cases, you will be notified of identification results within two business days. Please note: residents must live in Contra Costa County, and must provide an actual sample of the pest itself for identification (we do not ac