The short version
Spider control in Colorado involves sealing entry points, reducing clutter, and targeted treatments for dangerous species like black widows. Most spiders are harmless, but professional help ensures safety and long-term results.
- Only black widow and brown recluse spiders are medically significant in the US; brown recluse is rare in Colorado.
- Peak spider season in Colorado is late summer through fall (August–October) when males roam for mates.
- Professional treatment costs $150–$400 and includes interior and exterior applications.
- Prevention starts with sealing cracks, reducing outdoor lighting, and keeping vegetation away from your home.
- DIY methods help with occasional spiders, but infestations or dangerous species require a pro.
- Research: Glue traps are a monitoring tool as much as a treatment, and Local quotes vary; ask for a written estimate.
For homeowners, families with children or pets, and landlords in Colorado who want to understand spider control. Whether you're dealing with occasional sightings or a persistent problem, you'll find practical advice to protect your home and loved ones.
What to look for
Colorado's semi-arid climate and varied geography—from the Eastern Plains to the Rocky Mountains—create ideal conditions for many spider species. The most concerning is the western black widow (Latrodectus hesperus), which is common statewide, especially in dry, sheltered areas like woodpiles, garages, and crawlspaces. Brown recluse spiders, while rare in Colorado, have been introduced occasionally via shipped goods. Their range is concentrated in the central and southern US, not the Rockies. Most other spiders in Colorado, such as cellar spiders, jumping spiders, and wolf spiders, are harmless and help control pests like flies and mosquitoes. However, their webs and presence can be a nuisance, and some people are arachnophobic. Infestations typically occur when spiders find consistent food sources and entry points. Cracks in foundations, gaps around windows and doors, and open vents are common access routes. Once inside, they thrive in basements, attics, and cluttered areas.
- 1Frequent sightings of spiders, especially multiple individuals of the same species.
- 2Webs in corners, ceilings, windowsills, and undisturbed areas.
- 3Egg sacs—small, round, silken bundles—attached to webs or hidden in crevices.
- 4Prey remains like small insect wings or exoskeletons near webs.
- 5Spiders appearing in sinks or bathtubs, often seeking water.
- 6Bite marks on skin (though most spider bites go unnoticed or are misidentified).
Why it’s worth acting soon
- Black widow bites can cause severe pain, muscle cramps, and systemic symptoms; medical attention is needed.
- Spiders reproduce quickly; a single egg sac can contain hundreds of spiderlings.
- Infestations attract other pests if spiders die and their bodies decompose.
- Stains from spider droppings or webbing can damage walls and fabrics.
- Untreated infestations can worsen over time, requiring more expensive treatments.
in the U.S. are the black widow and brown recluseMedically significant spidersUS CDC Treatment options and typical costs
Interior and Exterior Perimeter Treatment
$150-$400
A licensed technician applies a liquid insecticide or microencapsulated formulation around the home’s foundation, entry points, and interior baseboards. This creates a barrier that kills spiders on contact and provides residual protection.
- Time
- Lasts 2-4 months; reapplied seasonally
- Best for
- General prevention and active infestations
Dust and Void Treatment
$200-$500
Insecticidal dust is applied into wall voids, attics, crawlspaces, and other hidden areas where spiders harbor. This is effective for long-term control in hard-to-reach spaces.
- Time
- Lasts 6-12 months in undisturbed areas
- Best for
- Infestations in voids or crawlspaces
Web Removal and Targeted Spot Treatment
$100-$300
Technicians manually remove webs and egg sacs, then apply a residual spray to specific areas like eaves, porches, and garages. This is often combined with sealing measures.
- Time
- Lasts 1-2 months; frequent re-treatment may be needed
- Best for
- Visible webs and outdoor infestations
Prices are typical published ranges. Ask what’s included before you compare quotes.
Basements stay dark, damp and quiet, which is everything a spider wants.Understanding Spider Behavior in Colorado.
This affects spider activity. On the plains, common house spiders and black widows thrive in hot, dry conditions. In mountain towns like Aspen or Breckenridge, you'll find more wolf spiders and funnel weavers that prefer cooler, moist environments. Fall is the peak season statewide because male spiders wander in search of mates and warmth, often entering homes through cracks and open doors. Understanding these patterns helps target prevention and treatment. For example, in Denver, basements and garages are prime black widow habitats due to stable temperatures and hiding spots. In Colorado Springs, window wells are common entry points. Knowing your local species and conditions is the first step to effective control. Colorado's climate varies dramatically—from the arid Eastern Plains to the high-altitude Rockies.
spiders activity by season.
In Colorado, checking the foundation, gaps around doors and windows, and any moisture or clutter near the structure usually turns up the conditions that are letting them in. Scheduling before the busy stretch, rather than after it, tends to mean faster service and a more accurate quote, and a local provider can point out the conditions that matter most in Colorado. The most useful first step in Colorado is to note where you have seen spiders and when they appear, because that timeline is what lets a provider focus on the right area instead of treating the whole property.
Mesh and sealant around a pipe entry close off a gap spiders would otherwise use.The Truth About Spider Bites in Colorado.
The CDC notes that most suspected spider bites are actually from other arthropods or skin infections. In Colorado, only the black widow is a genuine concern. Black widows are shy and only bite when provoked, such as when pressed against skin. Their venom is neurotoxic, causing symptoms like muscle cramps, nausea, and difficulty breathing—seek medical attention. Brown recluse spiders are not established in Colorado; occasional finds are from imported goods. Other spiders, like wolf spiders, may bite in defense, but their venom is mild. Most bites cause temporary redness and swelling. To reduce risk, wear gloves when handling woodpiles or boxes, and shake out clothing and shoes left on the floor. If bitten, clean the area and apply ice; monitor for severe symptoms and see a doctor if concerned. Despite common fears, spider bites are rare.
Integrated Pest Management (IPM) for Spiders.
Start by removing webs and egg sacs with a vacuum or broom, then find the entry points and seal them. Reduce hiding spots by clearing clutter in basements, garages and attics. Outdoors, keep the yard tidy and move woodpiles away from the house. Use yellow or warm-toned bulbs to draw fewer insects. If treatment is still needed, a pro can put a light dust into voids and treat the exterior perimeter rather than spraying rooms. IPM keeps product use low while still keeping spiders in check. Integrated pest management for spiders combines cleanup, sealing gaps and targeted treatment.
What affects the price
- Home size and number of stories—larger homes require more product and labor.
- Severity of infestation—heavy infestations may need multiple treatments.
- Type of treatment—dusting voids costs more than perimeter spraying.
- Accessibility—crawlspaces, attics, and high ceilings increase labor.
- Season—peak season (fall) may have higher demand and prices.
- Geographic location—urban areas like Denver may have different pricing than rural areas.
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What's your biggest concern about spiders at home?
When to call for help
Call a professional if you see black widow spiders or suspect brown recluse, if you have a severe infestation with multiple spiders daily, if you or a family member is bitten, or if DIY methods fail after two weeks. Professionals have the tools and expertise to safely identify and eliminate dangerous species and ensure long-term prevention.
What you can do yourself
Professionals use specialized products that are more effective and longer-lasting, and they can identify and treat the root cause. For dangerous species, professional treatment is strongly recommended to avoid risk of bites. The cost of a professional service is often less than repeated DIY attempts. DIY methods like sealing cracks, reducing clutter, and using sticky traps can manage occasional spiders. Over-the-counter sprays provide short-term relief but often miss hidden hiding spots.
Where you live matters
The Eastern Plains, with agricultural fields, see higher populations of wolf spiders and other hunters. Across the state, fall is the busiest time for spider calls. Homeowners in newer developments often experience fewer spider issues due to modern construction, while older homes in neighborhoods like Denver's Capitol Hill or Boulder's University Hill have more cracks and crevices that spiders exploit. Local technicians adapt treatment to Colorado's microclimates and building types. Colorado's geography creates distinct spider control challenges. In Denver and the Front Range, the dry climate combined with urban landscaping attracts black widows to garages, sheds, and rock piles. In mountain towns like Durango or Telluride, cooler summers shift spider activity to earlier in the year, and species like the hobo spider (Eratigena agrestis) are more common, though recent research suggests its venom is not as dangerous as once thought.
Simple ways to keep spiders away
- Seal cracks and gaps around windows, doors, and foundations with caulk or weatherstripping.
- Install door sweeps and repair torn screens.
- Reduce outdoor lighting or use yellow bug lights; lights attract insects, which attract spiders.
- Keep vegetation, woodpiles, and debris at least 2 feet from your home's foundation.
- Declutter basements, attics, and garages; store items in sealed plastic bins.
- Vacuum regularly, especially corners and under furniture, to remove webs and egg sacs.
- Remove webs immediately to discourage re-webbing.
Monitors along baseboards show whether spider numbers are actually falling after treatment.Did you know?
Weight for weight, spider silk is stronger than steel.
Spiders can't chew. They liquefy a meal first and drink it.
Some spider species can survive underwater for hours by trapping air bubbles in their hairs.
Questions people ask
Are all spiders dangerous?
No. In the US, only two groups are medically significant: black widows and brown recluses. In Colorado, black widows are present, but brown recluses are rare. Most household spiders are harmless and help control pests.
When is spider season in Colorado?
Spider activity peaks from August to October as males roam to mate and seek warmth indoors. You may see more spiders during this time, but they can be active year-round in heated homes.
How much does professional spider control cost?
Typical prices range from $150 to $400 for an interior and exterior treatment. Costs vary based on home size, infestation severity, and treatment type.
Can I get rid of spiders myself?
DIY methods like sealing cracks, using sticky traps, and reducing clutter can help manage occasional spiders. However, for persistent infestations or dangerous species, professional treatment is more effective.
How do I identify a black widow spider?
Females are glossy black with a red hourglass marking on the underside of the abdomen. They are about 1.5 inches including leg span. Males are smaller and lighter. They prefer dark, sheltered areas like woodpiles and garages.
What should I do if I see a brown recluse in Colorado?
Brown recluses are not native to Colorado. If you suspect one, capture it (if safe) and contact a professional for identification. They are light brown with a violin-shaped marking on the back. Most sightings are misidentified.
What is the most common spider found inside homes?
In Colorado, most spiders are harmless and beneficial, so the goal is usually to remove the webs and egg sacs and reduce the insects they feed on. In Colorado, only the black widow and brown recluse are medically significant in the U.S., and they are identified by their markings.
Sources (12)
The facts in this article come from the public sources listed above. Every home is different, so ask the company you talk to about pricing and what’s included. Published by Spider Exterminator · Updated September 11, 2026 · How we write these guides