The short version
Most spiders in Ann Arbor are harmless. Black widows live here, as in every lower-48 state. Ann Arbor 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.
Homeowners and renters in Ann Arbor who'd like fewer spiders, and peace of mind about the dangerous ones.
What to look for
Spiders follow their food. More insects means more spiders. Most are harmless and even helpful. Webs and egg sacs keep the cycle going.
- 1Spiders wandering across walls at night.
- 2Egg sacs, round or teardrop-shaped, tucked in eaves and frames.
- 3A pale spider in a silk retreat high on a wall.
- 4Webs behind shutters, meter boxes and utility panels.
- 5Dead insects wrapped in silk along ledges.
- 6Many tiny spiders in one spot after a hatch.
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
A pro in Ann Arbor starts by walking the exterior, garage, basement and eaves with a flashlight, noting webs and where insects gather. The goal is to name the species before deciding anything.
- Time
- 45–90 minutes
- Best for
- Every job; the species decides how much to do
Exterior Perimeter Treatment and Void Dusting
$150–$350
Sprays alone do a mediocre job on spiders, which is why Ann Arbor pros pair them with dusting. A light dust goes into weep holes, voids and behind fixtures.
- Time
- 45–120 minutes
- Best for
- Heavy exterior activity, widows or recluses confirmed
Sealing Gaps, Lighting and Prey Reduction
$150–$450
Sealing gaps also cuts their food supply. Indoor spiders eat flies, silverfish and pantry pests. Fixing those problems starves the spiders.
- Time
- 1–4 hours
- Best for
- Long-term reduction; homes near woods, water or fields
Monitoring and Follow-Up
$50–$150 per visit
Ask what the follow-up visit found. Tracking traps shows whether the plan works.
- 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.
Spiders slip into attics through soffit and gable vents, then settle where nobody disturbs them.Which spiders live around Ann Arbor.
Most suspects turn out to be harmless look-alikes. Most spiders in Ann Arbor homes are house spiders, cellar spiders, jumping spiders and wolf spiders. All are harmless to people. Around Ann Arbor, they're northern black widows, usually hiding under decks, grills and meter covers. Brown recluses don't live around Ann Arbor.
Local spiders conditions in Ann Arbor.
A provider who works Ann Arbor and Michigan 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. Ann Arbor sits in a humid continental climate, and that sets the pace for spider activity here: late summer through fall (August-October). Across Ann Arbor, the area is mostly urban, 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 Ann Arbor usually starts outside and works inward, checking the foundation, gaps around doors and windows, and any moisture or clutter near the structure first. Knowing Ann Arbor'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 vent that closes properly keeps spiders from using it as a winter doorway.When you’ll see more of them.
Clear egg sacs in winter. You'll see the most in late summer and fall. That's when males wander. Winter lows around 17°F in Ann Arbor slow spiders outside, but house spiders carry on indoors. Spring brings a new hatch.
Where they hide in houses here.
Clutter gives them endless hiding spots. Plenty of homes in Ann Arbor have basements, and basements are spider central. Check window wells, storage areas and the sill plate.
A year of spiders in Ann Arbor.
- Spring: new spiderlings hatch. Vacuum webs and egg sacs. - Summer: highs near 83°F in Ann Arbor bring more insects, and more spiders. - Fall: males wander indoors. Peak spider season. - Winter: with lows near 17°F in Ann Arbor, 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.
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. Wash the bite with soap and water.
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.
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. Most spiders are no threat to pets.
What a spider visit looks like.
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. Most visits take about an hour.
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
- Crawl space or basement access and moisture.
- Eave depth and roofline height.
- Local labor rates and travel distance.
- Season and how heavy current activity is.
- Bundling with an existing general pest plan.
- Inclusion of web and egg-sac removal.
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What's your biggest concern about spiders?
When to call for help
High eaves and attics are worth leaving to a pro. Call if a black widow is near where kids play. if spiders keep coming back after cleaning.
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 Ann Arbor
Ann Arbor has a humid continental climate, and spiders activity here tends to follow late summer through fall (August-October). An inspection in Ann Arbor that starts outside and works inward usually finds the entry points, moisture, and shelter that matter most before anyone treats. With about 36 inches of rain a year and humidity near 72%, Ann Arbor supports plenty of insects, and spiders follow them. In denser parts of Ann Arbor, spiders favor stairwells, garages, basements and window frames.
Local research
Spiders in Ann Arbor, MI: what the public record shows
Before you compare quotes, it helps to know which spiders actually live in Michigan, when they are busiest around Ann Arbor, and what the state figures look like. Everything below links to the agency or university page it came from.
When spiders are busiest around Ann Arbor
Late summer–early fall. Hunting spiders 'may enter into homes accidentally, particularly in the fall' and 'do not survive well indoors and usually do not reproduce indoors'. 'Funnel web spiders are the most common spiders found in homes, particularly during late summer and early fall'. 'The brown recluse (Loxoceles reclusa) is rare in Colorado because of our cold winters and dry climate' (same source), and 'Neither black widow spiders or brown recluse are native to the upper Midwest and are rarely encountered' (UMN). Cobweb and cellar spiders persist indoors year-round.
Based on Ann Arbor’s humid continental climate profile.
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: CDC/NIOSH. Figures are quoted as the source prints them. How we check our sources
Simple ways to keep spiders away
- Trim shrubs a foot back from siding.
- Keep beds a few inches from the wall.
- Install door sweeps on every exterior door.
- Repair torn window and vent screens.
- Vacuum webs and egg sacs weekly during warm months.
- 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?
Spiderlings travel miles by ballooning on silk threads
Wolf spider mothers carry hundreds of spiderlings on their backs
Questions people ask
Can I just leave the spiders alone?
Most house spiders are harmless and eat other pests. Widows are the exception, so check under outdoor furniture.
How long does spider treatment take to work?
You'll usually see fewer within a week or two. Webs and egg sacs need clearing too, or new spiders hatch.
Is spider treatment safe for pets and children?
Keep kids and pets away until treated areas dry. Ask what product they'll use. Applied by the label, yes.
What does a professional spider treatment involve?
Then they remove webs and egg sacs and seal gaps. Last comes a targeted treatment in cracks and voids. An inspection to identify the spiders first.
How do I know if I have a black widow?
They hide under furniture, grills and meter covers. Don't handle it. Look for a shiny black spider with a red hourglass underneath.
How much does a spider dust treatment cost?
Dusting voids and cracks is the least expensive professional spider treatment, according to Local quotes vary; ask for a written estimate. The useful next step in Ann Arbor is an inspection that pins down the source rather than a guess from national numbers.
Does every house have spiders?
Across Ann Arbor, 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. Across Ann Arbor, only the black widow and brown recluse are medically significant in the U.S., and they are identified by their markings.
Are there dangerous spiders in Ann Arbor?
Black widows, yes, as almost everywhere. Most other spiders here are harmless.
When are spiders worst in Ann Arbor?
Late summer and fall, when males wander.
Nearby cities
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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