From the dense forests to our urban homes, spiders are a vital part of the Pacific Northwest ecosystem. While most are harmless and even beneficial house guests, knowing which ones are crawling in your corner is crucial for peace of mind. This comprehensive guide will help you identify the most common spiders in Washington State, separate fact from fiction, and show you how to manage them safely and effectively.
The 8 Most Common Spiders in Western Washington Homes
1. Giant House Spider Eratigena atrica
- Identification: Large legs pan up to 4 inches, brown with lighter markings, and very fast-moving.
- Habitat: Often found in garages, basements, and behind furniture in the fall when males wander indoors looking for mates.
- The Truth: They are not aggressive and their venom is not medically significant to humans. Their large size and speed are their primary defense.
2. Cross Orbweaver Araneus diadematus
- Identification: The classic “halloween” spider. Plump, orange-to-brown abdomen with white cross-like markings. Builds large, intricate circular webs.
- Habitat: Gardens, window frames, and porch lights where flying insects are abundant.
- The Truth: Completely harmless and excellent for natural pest control. They are a gardener’s best friend.
3. Hobo Spider Eratigena agrestis
- Identification: Brown with a herringbone pattern on the abdomen. Builds funnel-shaped webs in dark, undisturbed areas.
- Habitat: Basements, window wells, and crawl spaces.
- The Myth: Once thought to have necrotic venom, this has been largely debunked by scientific research. The CDC no longer lists it as a medically important species. Its bite is typically no worse than a bee sting.
4. Cellar Spider aka “Daddy Long Legs”
- Identification: Extremely long, thin legs and a small, gray body. Often seen vibrating rapidly in its messy web when disturbed.
- Habitat: As the name implies, damp cellars, crawl spaces, and garages.
- The Truth: Completely harmless. They are known to catch and eat other spiders, including house spiders.
5. Black Widow (Latrodectus hesperus)
- Identification: Shiny, jet-black with a distinct red hourglass on the underside of the abdomen. The body is round and bulbous.
- Habitat: Prefers dark, undisturbed clutter like woodpiles, sheds, and under decks. They are not common inside Seattle homes but can be found in the greater PNW region.
- The Risk: This is the only spider in our area with venom that is medically significant to humans. A bite requires medical attention. They are non aggressive and only bite in defense.
6. Yellow Sac Spider
- Identification: Pale yellow or beige, with a slightly darker stripe down its back. They do not build webs but instead create silken “sac” retreats in corners or on ceilings.
- Habitat: Often found indoors year-round, sometimes walking on walls at night.
- The Truth: Their bite can be painful and may cause a red, itchy welt, but it is not considered dangerous.
Spider Identification Chart
| Spider | Color/Marking | Web Type | Danger Level |
|---|---|---|---|
| Giant House Spider | Brown, large size | Funnel web | Low |
| Cross Orbweaver | Orange/brown with white “cross” | Orb web | None |
| Hobo Spider | Brown, herringbone abdomen | Funnel web | Low |
| Cellar Spider | Pale, very long legs | Messy/tangled web | None |
| Black Widow | Shiny black, red hourglass | Irregular/tangled web | High |
| Yellow Sac Spider | Pale yellow/beige | Silken “sac” | Low-Moderate |
The Truth About Spider Bites and Venom
Myth: Spider bites are common and often cause severe skin lesions.
Fact: The vast majority of suspected “spider bites” are actually bites from other insects like fleas or bed bugs, or skin infections. Spiders are reluctant to bite and usually only do so as a last resort when pressed against the skin.
When to Be Concerned: Signs of a Black Widow Bite
If you suspect you’ve been bitten by a Black Widow, seek medical attention. Symptoms can include:
- Intense pain at the bite site that spreads to the abdomen or back
- Muscle cramps and rigidity
- Nausea and vomiting
- Difficulty breathing
Integrated Pest Management: The Smart Way to Control Spiders
The goal is not to eradicate all spiders an impossible and ecologically unsound task but to manage their presence inside your home.
1. Prevention is Key: Make Your Home Less Attractive
- Eliminate Hiding Spots: Reduce clutter in basements, garages, and attics.
- Seal Entry Points: Caulk cracks around windows, doors, and foundation lines. Install door sweeps.
- Turn Off the Buffet: Spiders go where their food is. Controlling other insects in your home with general pest control services is the most effective long term solution.
- Reduce Moisture: Fix leaky pipes and use a dehumidifier in damp areas to make the environment less hospitable.
2. Non Chemical Control
- Vacuuming: This is the most effective method. Regularly vacuum spiders, egg sacs, and webs.
- The Cup & Card Method: Safely capture and release spiders outdoors.
- Reduce Outdoor Lighting: Switch to yellow sodium vapor bulbs, which attract fewer insects, which in turn attract fewer spiders.
3. When to Call a Professional
Consider calling a local spider control expert if:
- You have identified or suspect a Black Widow infestation.
- You are dealing with a large number of spiders and cannot control the population.
- You have a severe allergy to insect or arachnid venom.
The Beneficial Role of Spiders
Before you squish, remember: spiders are nature’s pest control. They consume vast quantities of insects, including mosquitoes, flies, roaches, and agricultural pests. The spiders in your garden are working for you for free!
Found a Spider and Need Help?
If you’re dealing with recurring spiders or have found a potentially dangerous species like a Black Widow, don’t take chances. Our local experts can identify the species, locate the source, and implement a safe, targeted control plan.
Contact us for a professional identification and solution.
Call (206) 571-7580