Mosquitoes in Castaic
The yellow fever mosquito (Aedes aegypti) has been found in Castaic. It's the small black-and-white mosquito that bites ankles in the daytime and breeds in containers as small as a bottle cap.
Yellow fever mosquito
Aedes aegyptiFound hereBlack with white-banded legs and a silver lyre on its back. Bites in the daytime, low on the legs.
Asian tiger mosquito
Aedes albopictusNot on the list hereBlack with one white stripe down its back. Also a daytime biter.
From the California Department of Public Health list, updated May 1, 2026. Not on the list means it hasn't been detected, not that it can't show up.
Not sure it's mosquitoes? Answer three questions to tell ankle biters from fleas, bed bugs and no-see-ums.
What that means for your yard
Irrigated landscaping, yard drains and decorative water features in newer subdivisions are common sources. None of the 2 Santa Clarita Valley communities on the state list currently has the Asian tiger mosquito; all have the yellow fever mosquito.
These mosquitoes rarely fly far from where they hatched. If you're getting bitten on your patio in the afternoon, the water they came from is probably in your yard or the one next door.
West Nile in Castaic
West Nile is active here. The Greater LA County Vector Control District's 2026 detection list includes 1 West Nile–positive mosquito sample (the first on September 18) in Castaic so far this year. Those come from Culex, the brown mosquitoes that bite at dusk and at night, so use repellent in the evening too.
Source: Greater LA County Vector Control District, 2026 year to date, checked October 1, 2026.
Who to call for a free inspection
Castaic is an unincorporated community, and which public district serves you depends on your exact address. Enter your ZIP in the state's lookup to get the right agency and phone number.
Ten-minute yard check
- Dump plant saucers, buckets, toys and anything else holding water, then scrub the sides. Eggs stick to the walls.
- Change pet water and bird baths at least once a week.
- Clear clogged rain gutters and yard drains.
- Screen rain barrels with fine mesh, and treat water you can't dump with a Bti larvicide.
- Report a green, neglected pool to your district.
Hiring a mosquito service in Castaic
If the source isn't on your property or you've done the yard check and still can't sit outside, a licensed company can treat the shady spots where mosquitoes rest and the breeding spots you can't empty. Typical prices: $100–$300 for a one-time treatment, $400–$1,000 for a season.
Ask for the company's California license number before they treat anything. Companies that treat in or around homes for hire need a license from the Structural Pest Control Board or the Department of Pesticide Regulation.