Spiders in the San Gabriel Valley
Most spiders are harmless web-builders. Here's how to tell them from the one that matters — the black widow — and how to keep numbers down.
- Most are harmless web-builders eating other bugs
- Black widow: glossy black, red hourglass underside
- Black widows: messy webs in garages, woodpiles, boxes
- Spiders follow their food (other insects)
- Papery egg sacs signal a growing population
What they look like
The large majority of spiders around SGV homes are harmless web-builders — cellar spiders, common house spiders and orb-weavers — that actually help by eating other insects. The one that matters is the black widow: glossy black with a red hourglass marking on the underside of its abdomen.
You may also see the brown widow, now common in Southern California — tan and mottled, with a spiky, sputnik-shaped egg sac. An honest myth-buster: the brown recluse is not established in the San Gabriel Valley, so most 'recluse bites' here are something else.
Black widow vs. brown widow vs. common web-builders
| Feature | Black widow | Brown widow | Orb-weaver / house spider |
|---|---|---|---|
| Appearance | Glossy black, red hourglass | Tan/mottled, orange (not red) hourglass | Brown/grey, varied |
| Web type | Messy, strong tangle | Messy tangle | Neat wheel or cobweb |
| Where found | Garages, woodpiles, boxes | Eaves, furniture, walls | Lights, eaves, windows |
| Level of concern | Bite needs medical care | Milder than black widow | Harmless, helpful |
Where they live
Black and brown widows like quiet, undisturbed, protected spots: garages, woodpiles, block walls, meter and irrigation boxes, eaves, and the underside of patio furniture. Harmless web-builders set up wherever flying insects gather — around exterior lights, eaves and windows.
Because spiders follow their food, a spider problem is usually really an insect problem: lots of webs means lots of prey nearby.
Signs of a spider problem
Web type is the quickest clue. A neat, wheel-shaped web is almost always a harmless orb-weaver. A messy, tangled web low in a garage corner or wall void means a cobweb spider — which could be a harmless house spider or a widow, so confirm by spotting the spider itself (glossy black with a red hourglass) and its egg sac. Papery or spiky egg sacs signal a growing population.
Finding several widows — or their egg sacs — around play areas, garages or patios is the point to take action.
How spiders are controlled
Control starts mechanically: knocking down webs and egg sacs, clearing harborage like woodpiles and clutter, and reducing the insect prey that draws spiders in (managing exterior lighting helps). A targeted perimeter treatment then keeps numbers down around the home.
A black widow bite can need medical attention, so it's best to leave removal of widows and their egg sacs to a pro — our spider control and this guide to black widows in the SGV cover how we handle them. Since spiders track their prey, knocking down what they eat — like the crickets that gather in garages — helps too.
Related Pests
Quick Answers
Quick Answers.
How do I identify a black widow?
Look for a glossy, jet-black spider with a red hourglass mark on the underside of its round abdomen, usually hanging upside-down in a messy, strong web. They favor garages, woodpiles, block walls and meter boxes.
Are black widow spiders dangerous?
Their venom is potent, and a bite can cause significant pain, cramping and other symptoms that may need medical attention — but bites are uncommon because widows are shy and usually bite only when trapped or pressed against skin. Children and pets warrant extra care.
Why do I have so many spiders?
Spiders follow their food, so lots of spiders usually means lots of insects — often drawn to exterior lights, eaves and damp areas. Reduce the prey and harborage and the spider numbers drop with them.
How do I keep spiders out of the garage?
Knock down webs and egg sacs, clear clutter and woodpiles where widows hide, manage moisture, and cut the insect prey that draws them in. A perimeter treatment around the garage and home keeps numbers down.
Are brown recluse spiders in the San Gabriel Valley?
No — the brown recluse is not established in Southern California, so a 'recluse bite' here is almost always something else. The spiders worth knowing locally are the black widow and the increasingly common brown widow.
How do I get rid of black widow egg sacs?
Because disturbing a widow risks a bite, it's best to have egg sacs removed by a pro rather than handling them yourself. Removing the sacs along with the adults and treating their harborage is what stops the next generation.
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