Ticks on the Central Coast and in the Bay Area

1Which ticks bite people here

UC IPM counts 48 tick species established in California, but only 6 attach to people with any regularity. CDPH's identification card names the four a homeowner is most likely to meet: the western blacklegged tick (Ixodes pacificus), the Pacific Coast tick (Dermacentor occidentalis), the American dog tick (Dermacentor similis), and the brown dog tick (Rhipicephalus sanguineus).

The western blacklegged tick gets the most attention because it carries the bacteria behind Lyme disease. UC IPM reports it in 56 of California's 58 counties and notes that it attaches to people more often than any other tick in the state. Where it lives depends on its life stage. CDPH places nymphs in leaf litter and on rocks, logs, tree trunks and fallen branches under oaks and in other shaded natural areas, and adults on the tips of tall grass and shrubs, often along trails. Only nymphs and adult females transmit the Lyme bacteria.

The brown dog tick is the exception to the outdoors rule. CDPH notes that it can be found in or around the home and in dog kennels, so a tick problem that seems to start indoors near where a dog sleeps points toward this species rather than a hiking trail.

• Western blacklegged tick: oak woodland leaf litter (nymphs) and trailside grass and brush (adults). Linked by CDPH to Lyme disease, anaplasmosis and hard tick relapsing fever.
• Pacific Coast tick: one of the three common biters Alameda County's district names, waiting on grass and branches at trail edges. Linked to Pacific Coast tick fever, spotted fevers and tularemia.
• American dog tick: the third of those common trailside biters. Linked to spotted fevers and tularemia.
• Brown dog tick: in and around homes and kennels where dogs live. Linked to spotted fever.

Sources: Common Ticks in California · Lyme Disease · Pest Notes: Lyme Disease in California · Spotted Fever Group Rickettsia (RMSF and PCTF) · Ticks

2When ticks are active on the coast and in the Bay

There is no tick-free month in California. CDPH says ticks can turn up at any time of year and are more abundant in spring and winter. The two Lyme-carrying stages of the western blacklegged tick split the calendar between them: adults become active in the fall, usually around Halloween, and stay active into early spring, while nymphs take over in spring and early summer.

Nymphs are the harder stage to avoid. They live down in the leaf litter, and CDPH's 2025 surveillance found the Lyme bacteria in 4.6 percent of nymphs tested statewide, against 0.9 percent of adults. The Pacific Coast tick and the American dog tick follow a different clock, with adults and nymphs most active from early spring to mid-summer. CDPH puts the lowest bite risk in late summer, and adds that ticks may still be active then in moist, cool areas, which describes a fair amount of the coast.

Sources: Tick Bite Prevention · Seasonal Tick Risk · Tick-Borne Diseases: Information for Health Professionals · Vector-Borne Disease Section Annual Report, 2025

3How Lyme disease risk compares across the seven counties

CDPH lists the San Francisco Bay Area and the Central Coast among the regions of California where people are most at risk of Lyme disease. Inside that region the numbers are uneven. In CDPH's count of confirmed cases from 2016 through 2025, Santa Cruz County residents had a Lyme disease rate of 3.16 per 100,000 people per year, about sixteen times the statewide rate of 0.20. UC IPM names Santa Cruz County as one of six California counties where more than 10 percent of the land is forest that may carry a high risk of exposure to nymphs.

The same CDPH table puts San Francisco at 0.76, Alameda at 0.37, Santa Clara at 0.32, San Mateo at 0.21, San Benito at 0.16 and Monterey at 0.11. Read those figures with two cautions from CDPH: cases are counted by where a person lives, not where they were bitten, and about 1 in 3 Lyme disease cases in California are in people infected while traveling outside the state.

Lyme disease is not the only concern. CDPH notes that the bacteria behind spotted fevers can infect a person shortly after a tick attaches, and in its 2025 testing 8 of 115 adult Pacific Coast ticks from Monterey County (7 percent) carried a spotted fever group Rickettsia. That is why prompt removal matters for every species, not only the blacklegged tick.

Sources: Lyme Disease · Vector-Borne Disease Section Annual Report, 2025 · Spotted Fever Group Rickettsia (RMSF and PCTF) · Pest Notes: Lyme Disease in California

4How to remove an attached tick

CDPH's instructions are short, and they work best when followed exactly. Speed matters: CDPH says an infected western blacklegged tick has to feed for at least 24 hours before it can pass on the Lyme bacteria.

1. 1

   Use fine-tipped tweezers

   CDPH says a plain set of fine-tipped tweezers works well. CDC advises grasping the tick as close to the skin's surface as you can.

2. 2

   Pull slowly and straight out

   Pull the tick up and straight out, away from the skin, with slow and steady pressure. Do not twist or jerk it. If mouthparts stay in the skin and do not come out easily, leave the area alone and let the skin heal.

3. 3

   Clean up, and do not crush the tick

   Wash your hands and the bite with soap and water, then apply an antiseptic or antibiotic ointment. Never crush a tick with your fingers.

4. 4

   Keep the tick for identification

   Take a photo if you can, then seal the tick in a bag or tape it to a piece of paper with clear tape. Several county districts will identify the species, and CDPH notes that knowing the species can help a clinician.

Sources: Tick Bite Prevention · Lyme Disease · Tick-Borne Diseases: Information for Health Professionals · Tick Removal: What to Do After a Tick Bite

5Who will identify a tick for you

Four of the seven counties have a public agency that identifies ticks for residents. The San Mateo, Santa Clara and Alameda agencies say plainly that they do not test residents' ticks for disease, and CDPH does not recommend tick testing for medical decisions: the tick may not be a species that carries Lyme disease, lab accuracy varies, and treatment should not hinge on the result. Bring symptoms to a clinician, and bring the tick to the district if you want to know what it was.

• Santa Cruz County Mosquito and Vector Control identifies ticks at no charge from an emailed photo or a sample dropped at its Capitola Road office, and follows up with information on disease risk, removal and habitat.
• San Mateo County Mosquito and Vector Control District identifies resident-submitted ticks through a service request or an office visit. It does not test them for disease.
• Santa Clara County's vector control district offers free insect identification, ticks included, and refers tick disease testing questions to the County Public Health Laboratory.
• Alameda County Vector Control Services District identifies tick species and runs tick surveillance in regional parks and open spaces. It does not test ticks removed from people or pets.
• In Monterey, San Benito and San Francisco counties we found no published public tick identification program. The Monterey County Mosquito Abatement District does post tick biology pages.

Sources: Ticks · Ticks · Ticks · Ticks · Ticks · Tick Bite Prevention

6Where ticks live in a yard, and where they do not

CDPH's guidance for homeowners starts with a useful fact: ticks are usually not found out in open, sunny areas such as mowed lawns. They stay where there is cover: leaf litter, unmown grass and brush. In a typical yard that means the back edge where lawn meets an unmanaged slope, the ground around a woodpile, or the strip under oaks.

The landscape changes CDPH recommends work on that edge. Remove leaf and grass litter, keep lawns and plantings trimmed, and lay a 3-foot border of gravel or wood chips between the lawn and any overgrown natural area. Move play equipment and patio furniture away from the yard's edges. Keep woodpiles neatly stacked and away from the house to reduce places where rodents can live, keep trash cans closed and do not overfill bird feeders. CDPH suggests 8-foot fencing where deer move through.

CDPH treats pesticides as a second step, for when landscaping has not reduced ticks enough, and asks homeowners to consult a pest control operator or the local vector control agency before applying anything. Any product used must be labeled for outdoor tick control, kept away from areas where bees, pets and people spend time, and applied in a way that keeps it out of waterways.

Sources: Controlling Ticks Around Your Home · Pest Notes: Lyme Disease in California

7Dogs, cats and the brown dog tick

Pets that go outdoors can pick up ticks and carry them inside, where those ticks can bite people later. CDPH recommends checking pets for ticks every day, especially after time outside, and using tick products on dogs and cats only as a veterinarian recommends. CDPH also notes that a canine Lyme disease vaccine exists, which is a question for your veterinarian.

The brown dog tick is the species most likely to settle in where a dog lives, in and around the home and in kennels. If you keep finding ticks on a dog that has not been on trails, or on walls and bedding near where the dog sleeps, have the tick identified. The answer changes the plan: a brown dog tick problem is worked indoors and around the dog's resting areas, while a western blacklegged tick points back to the yard edge and nearby woodland.

Sources: Tick Bite Prevention · Controlling Ticks Around Your Home · Common Ticks in California