Russian Hill Pest Control

Most Common Pests in San Francisco, CA

San Francisco is home to many species of insects, rodents, and wildlife. Learn more about the most common pests in the area by reading below.

Termites

San Francisco homeowners often suffer from termite infestations and damage. The Bay Area is home to two primary species: drywood and subterranean termites. Both species can cause significant damage to your home.

Drywood termites are a destructive species of termites in the US, with large populations in the Bay Area. Hidden deep within wood, drywood termites chew and grow their colonies, destroying wood from the inside out. Because wood contains certain levels of moisture, drywood termites can survive on wood alone as both a water and food source. Bubbles in wallpaper or wood flooring and small piles of wings are signs that drywood termites are infesting.

Cockroaches

Brown-banded, German, American, and Oriental cockroaches are the most abundant in San Francisco homes. Cockroach infestations most often begin when someone unknowingly brings an infested item into a home or building. Poor sanitation such as leaving out food or dirty dishes can encourage an infestation since this type of clutter provides an excellent food source for roaches.

Cockroaches also are drawn to less frequented areas near sewers and drainage where they can live in the moisture and clutter made by boxes and papers left in storage spaces, electrical rooms, or garages. American roaches usually originate from drains or sewers and make their way into working or living areas via the pipes and drains. The adults are very strong flyers, allowing them to easily migrate from home to home.

Mice

You might be surprised to hear how easy and common it is for a mice infestation to begin. Mice can squeeze through holes the size of a dime, making it possible for them to get into your home through even the smallest of holes or cracks on the exterior of your home. Once indoors, they quickly cause unsanitary conditions, leaving large amounts of droppings throughout your home as they move around at night. Mice can also contaminate food in easily penetrable or unsealed food containers. Their coats are full of natural oils that transfer as they scale walls or enter and exit through small spaces. These oily spots called “rub marks" can stain walls where openings exist.

Rats

Norway rats and roof rats are the most common rat species that infest homes in San Francisco and the Bay Area. Regardless of species, rat infestations can cause a lot of frustration and anxiety when homeowners have to deal with their presence.

Norway rats are ground-dwelling rodents that live in burrows within the ground. When faced with a cityscape, Norway rats will even chew through cracks in blacktop to burrow. They typically search for food outdoors, but many times will come inside manmade structures at night to gather food and return to their burrows. They can travel hundreds of feet which could mean that you might be suffering from your neighbor's rat issue or because of poor garbage storage from nearby businesses. As their name suggests, roof rats are skilled climbers, making their nests in higher areas like attics, drop ceilings, and even cabinets when living indoors.

Bed Bugs

Bed bug infestations occur when a human comes into contact with bed bugs and unknowingly brings them somewhere else. They are transported as stowaways, hiding in luggage, couches, beds, pillows, backpacks, and more. Bed bugs cling to moving items like briefcases and can easily fall off, allowing them to relocate and spread. It's also a common occurrence that bed bugs lay eggs on these items. As the host moves, they can fall off and hatch far away from where they originally came from.

Bed bugs prefer to hide in tight spaces like around mattress piping, in the corners of bed frames, within upholstered furniture, inside dresser drawers, and even behind light socket covers and hung artwork. If you find what looks like small marks made with a permanent marker on your bed sheets, bed bugs could be the culprit.

Silverfish

Silverfish find their way indoors while searching for shelter, moisture, and food. Easy entry points exist around your home such as windows, door frames, and utility pipes. They can also be brought in as stowaways in boxes or packages. Although silverfish don't cause structural damage to San Francisco homes or pass on disease-causing pathogens to humans, they do cause damage to books, wallpaper, paper goods, and sometimes clothing. Once the silverfish have established themselves inside, they can live for several weeks without any food source or water. However, if they find an abundant food source, they'll stay close by.

House Ants

No matter where you live in the Bay Area, house ants are an incredibly common household pest. House ants can enter your home through tiny spaces that you may not even think of. Small tears in window screening, exterior cracks, and gaps around windows and doors are some of the most common access points for ants. They can also be brought into the home by hitching a ride on potted plants or hanging baskets from garden centers.

Ants can be found in any part of your home, but the kitchen and bathroom are the most common because of the easily accessible water and food sources. Your home can easily suffer from ant infestations if food isn't stored properly, entry points aren't repaired or sealed, and wet wood or damp insulation exists.

Clothes Moths

Webbing clothes moths are a common moths species in San Francisco and throughout Northern California. Adult webbing clothes moths are rarely seen because they avoid the light. It's not uncommon that people typically do not know they have an infestation until the damage becomes apparent. Holes that suddenly appear in clothing, rugs, carpets, felt, upholstered furniture, and stored wool can indicate a clothes moth infestation. They are not an immediate health threat to humans, but they still are bothersome because of how destructive they can be to your garments and rugs. DIY products and methods can be costly, time-consuming, and ineffective against these challenging pests.

Spiders

The Bay Area is home to a wide variety of spiders including tarantulas, cellar spiders, black widow spiders, American house spiders, orb weavers, wolf spiders, and more. Although you could encounter many or all of these as a resident of San Francisco, the most common spider that infests homes is the American house spider. Secluded corners, cabinets, closets, and attics are ideal hiding places for American house spiders due to the low amount of foot traffic and human activity. American house spiders are typically harmless and feed on other small pests that could be lurking around your home.

Centipedes

House centipedes are a common household pest in San Francisco. They can be up to two inches long (some species are smaller and some are much larger) with a large abundance of many legs that propel them quickly when they dart across a room. Did you know centipedes can also scale walls? Although they are relatively harmless, centipedes can be alarming to unsuspecting homeowners. You are most likely to find centipedes living in your garage, storage spaces, and areas with higher moisture levels such as bathrooms, and under dishwashers and sinks. Their diet includes insects and spiders, so if there is an infestation of another pest, centipedes can thrive.

House Crickets

House crickets are a frequently found pest in San Francisco homes. These noisy pests can be found in laundry rooms, storage spaces, behind baseboards, under appliances, attics, and other spaces with less foot traffic in your home. Cricket infestations are not only difficult to control, but they are also very noisy while they chirp at night. House crickets will attack paper, silk, woolen items, fruits, vegetables and even rubber. However, unless large numbers occur, this damage is typically minor. Though they can be irritating and loud, house crickets are harmless to humans.

Paper Wasps

Paper wasps are small stinging insects that frequently nest on properties throughout the Bay Area. These flying pests build their nests virtually anywhere, inside window frames, on overhangs, in attic vents, under outdoor furniture, or on play equipment. They make nests outdoors that resemble an upside-down umbrella with a honeycomb pattern. Paper wasps scrape wood shavings off decks, wooden railings, wooden patio tables and chairs, and other wood around your property, turning it into a paste when mixed with their saliva. This mixture is used to construct their nest. Most paper wasp nests are light gray, but they can be different hues based on the color of the wood found in the area. Paper wasps are mildly aggressive and can sting if they feel threatened or if you get too close to the nest.