The short version
Most spiders in Centennial are harmless. Black widows live here, as in every lower-48 state. Centennial is outside the brown recluse range, so most 'recluses' here are look-alikes. Identify first, then treat.
- Most house spiders are harmless.
- Black widows live in every lower-48 state.
- Brown recluses don’t live here.
- Skip foggers; they don’t reach hiding spots.
- Yellow bug lights and door sweeps help a lot.
Anyone in Centennial who's spotted a spider and wants to know if it matters.
What to look for
Most are harmless and even helpful. Webs and egg sacs keep the cycle going. Spiders follow their food. More insects means more spiders.
- 1Webs under deck boards and outdoor furniture.
- 2Tan spider with a violin mark and six eyes.
- 3A pale spider in a silk retreat where wall meets ceiling.
- 4Small flying insects gathering under exterior lights.
- 5Egg sacs, round or teardrop-shaped, tucked in eaves and frames.
- 6Spiders in stored boxes, shoes or seldom-worn clothing.
Why it’s worth acting soon
- Egg sacs hatch hundreds of spiderlings.
- Webs build up in eaves, corners and garages.
- Widows nest under outdoor furniture and grills.
Treatment options and typical costs
Inspection and Species Identification
$75–$200
The inspection maps webs, entry cracks and what the spiders eat. Everything that follows is built on that map.
- Time
- 45–90 minutes
- Best for
- Every job; the species decides how much to do
Exterior Perimeter Treatment and Void Dusting
$150–$350
Ask what product is used and why it fits your Centennial situation. Labels vary, and the choice should be explained plainly.
- Time
- 45–120 minutes
- Best for
- Heavy exterior activity, widows or recluses confirmed
Sealing Gaps, Lighting and Prey Reduction
$150–$450
Spiders follow food. Fewer insects outside does more than any single treatment. Lighting and sealed gaps help most.
- Time
- 1–4 hours
- Best for
- Long-term reduction; homes near woods, water or fields
Monitoring and Follow-Up
$50–$150 per visit
Trap counts give an honest read. If numbers keep falling, the plan is working. If not, a good pro changes approach.
- Time
- 20–45 minutes
- Best for
- Confirming results; recluse or widow properties
Prices are typical published ranges. Ask what’s included before you compare quotes.
Where brown recluses live, they like quiet spots under beds and furniture, so a flashlight check along the frame is worth a minute.Which spiders live around Centennial.
Most spiders in Centennial homes are house spiders, cellar spiders, jumping spiders and wolf spiders. All are harmless to people. Around Centennial, they're western black widows, usually hiding under decks, grills and meter covers. Brown recluses don't live around Centennial. Most suspects turn out to be harmless look-alikes.
Local spiders conditions in Centennial.
Centennial sits in a semi-arid climate, and that sets the pace for spider activity here: late summer through fall (August-October). In Centennial, the area is mostly suburban, so spiders pressure can differ from one block to the next depending on how tight the entry points are and how much food, water, or shelter is close by. An inspection in Centennial usually starts outside and works inward, checking the foundation, gaps around doors and windows, and any moisture or clutter near the structure first. Knowing Centennial's seasonal timing lets you schedule treatment before the busy stretch rather than after it, which usually means faster service and a more accurate quote. A provider who works Centennial and Colorado every day can point out the specific conditions that matter most here, and getting the scope, price, and follow-up terms in writing makes it easier to compare options.
The gap under a door is one of the easiest ways in, for spiders and for the insects they follow.When you’ll see more of them.
You'll see the most in late summer and fall. That's when males wander. Winter lows around 18°F in Centennial slow spiders outside, but house spiders carry on indoors. Spring brings a new hatch. Clear egg sacs in winter.
Where they hide in houses here.
Plenty of homes in Centennial have basements, and basements are spider central. Check window wells, storage areas and the sill plate. Clutter gives them endless hiding spots.
A year of spiders in Centennial.
- Spring: new spiderlings hatch. Vacuum webs and egg sacs. - Summer: highs near 88°F in Centennial bring more insects, and more spiders. - Fall: males wander indoors. Peak spider season. - Winter: with lows near 18°F in Centennial, a good time to clear clutter and seal gaps.
Harmless or worth a closer look?
- Black widow: shiny black, red hourglass underneath. Leave it alone. - Brown recluse: tan, violin mark on its back, plain legs. - Wolf spider: big, hairy and fast. Harmless. - Cellar spider: tiny body, very long legs. Harmless. - Jumping spider: small, fuzzy, hops. Harmless. - Orb weaver: big round web outside. Harmless.
If you think you’ve been bitten.
Wash the bite with soap and water. Use a cool compress. Raise the area if you can. See a doctor for severe pain, cramping or spreading redness. If you can, safely catch the spider for identification.
Fewer spiders, the easy way.
- Lights: yellow bug lights draw fewer insects. - Gaps: add door sweeps and repair screens. - Clutter: store things in sealed plastic bins, not cardboard. - Webs: vacuum webs and egg sacs every few weeks. - Shoes and gloves: shake them out before use. - Beds: keep them a few inches from the wall.
Webs outside: leave some, clear some.
- Garden orb weavers: leave them. They catch flies and mosquitoes. - Doorways and porch lights: brush webs away weekly. - Eaves and window frames: a long-handled brush works well. - Woodpiles: keep them off the ground and away from the house. - Gloves: wear them when moving firewood, pots or patio cushions.
Spider myths.
- Swallowing spiders in your sleep: no evidence it happens. - Daddy longlegs are deadly: no. They’re harmless. - Spiders move in for winter: most house spiders never leave. - Every blister is a recluse bite: most aren’t spider bites.
Spiders and pets.
Most spiders are no threat to pets. A widow bite can sicken a dog or cat. your vet. Some sprays are risky for cats. Ask the company which products are cat-safe.
What a spider visit looks like.
Most visits take about an hour. The tech walks the outside first. They knock down webs and egg sacs around eaves and windows. They treat cracks, gaps and hiding spots, not open lawn. Inside, they focus on corners, closets and the garage.
Sticky traps tell you a lot.
Set sticky traps along baseboards, behind furniture and in the garage. Check them after a week. They show which spiders you have and where they travel.
Outdoor lights and spiders.
Porch lights draw insects, and insects draw spiders. Yellow bulbs attract fewer bugs. Motion-sensor lights help too.
Cellar spiders in the basement.
Long-legged cellar spiders hang in basement corners. They're harmless and even eat other spiders. A dehumidifier and a broom keep them in check.
Spiders in the garage.
Garages collect webs, boxes and insects. Store things in sealed bins off the floor. A door sweep and a sticky trap by the door help.
Questions to ask before you sign.
- Which spiders did you find? - Where will you treat, inside and out? - Is web and egg-sac removal included? - Will you seal gaps or add door sweeps? - What happens if they come back? - When can kids and pets go back in?
What affects the price
- Season and how heavy current activity is.
- Inclusion of web and egg-sac removal.
- Door sweeps, screens and sealing work.
- Exterior siding type and number of gaps.
- Whether a widow or recluse is confirmed.
- Whether outbuildings, sheds and decks are included.
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What's your biggest concern about spiders?
When to call for help
Call if a black widow is near where kids play. if spiders keep coming back after cleaning. High eaves and attics are worth leaving to a pro.
What you can do yourself
Skip foggers. They don't reach hiding spots. A pro adds targeted treatment in cracks and voids. Start simple. Switch to yellow bug lights. Add door sweeps and store things in sealed bins.
Spiders in Centennial
Centennial only gets about 16 inches of rain a year, so spiders gather where insects find water: garages, sprinkler zones and shaded walls. In Centennial's neighborhoods, eaves, porch lights, woodpiles and garages are spider favorites. Centennial has a semi-arid climate, and spiders activity here tends to pick up late summer through fall (August-October). In Centennial, most of the housing is suburban, so the usual entry points, moisture spots, and sheltered areas near the structure are what an inspection checks first. In Centennial, take a minute to note where you have seen activity and when it appears, so the inspection is faster and the quote more accurate. A local provider who knows Centennial and Colorado can point out the specific conditions that matter most here before you commit to a plan.
Local research
Spiders in Centennial, CO: what the public record shows
Before you compare quotes, it helps to know which spiders actually live in Colorado, when they are busiest around Centennial, and what the state figures look like. Everything below links to the agency or university page it came from.
Spider species recorded in Colorado
- Western black widow (Latrodectus hesperus) — 'The black widow spider, Latrodectus hesperus, is the most common harmful spider in California' and 'occur in most parts of California' (UC IPM); 'common in Colorado' (CSU); Lat…
- Funnel weavers (grass spiders) (Agelenidae) — 'The most common spiders found in homes, particularly during late summer and early fall' in Colorado (CSU).
When spiders are busiest around Centennial
'Funnel web spiders are the most common spiders found in homes, particularly during late summer and early fall'; 'Some spiders wander indoors in the early fall' (CSU).
'Widow spiders, particularly the western widow (Latrodectus hesperus), are common in Colorado' (CSU).
For context, nationally
- Throughout North America, but are most common in the southern and western United States — Black widow distribution. CDC/NIOSH
- In the midwestern and southern United States — Brown recluse distribution. CDC/NIOSH
Sources: Spiders in the Home (5.512); CDC/NIOSH; Pest Notes: Spiders (PN 7442). Figures are quoted as the source prints them. How we check our sources
Simple ways to keep spiders away
- Run a dehumidifier in damp basements.
- Clear leaf litter and debris from foundations.
- Keep beds a few inches from the wall.
- Seal gaps around pipes, cables and vents.
- Check meter boxes and grills before reaching in.
- Fix leaks and standing water in crawl spaces.
Under-sink cabinets get checked for gaps around pipes, which spiders and their prey both use.Did you know?
Wolf spider mothers carry hundreds of spiderlings on their backs
Jumping spiders see in color and plan their route before they pounce
Questions people ask
Do spider sprays actually work?
Store-bought sprays kill what they touch. They rarely reach hiding spots. Removing webs and egg sacs and sealing gaps works better.
Is spider treatment safe for pets and children?
Applied by the label, yes. Keep kids and pets away until treated areas dry. Ask what product they'll use.
What does a professional spider treatment involve?
An inspection to identify the spiders first. Then they remove webs and egg sacs and seal gaps. Last comes a targeted treatment in cracks and voids.
Why do spiders keep coming back after I clean?
Usually because the insects they eat are still around. Egg sacs and gaps around doors also keep them coming.
Do brown recluses live in my area?
Probably not. Colorado is outside the brown recluse range.
How much does a spider dust treatment cost?
Between $100 and $250 is Local quotes vary; ask for a written estimate. A good pro in Centennial can explain why their plan matches what they found at your place.
Was it really a spider bite?
Probably not. Three point eight percent of the 182 patients who came to one California emergency department with a suspected spider bite between 2006 and 2007 actually received a spider-bite diagnosis, according to Suchard's 2011 clinical study.
Are there dangerous spiders in Centennial?
Black widows, yes, as almost everywhere. Most other spiders here are harmless.
When are spiders worst in Centennial?
Late summer and fall, when males wander.
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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