Spiders are in your Maryland home for three reasons. There is food, there is shelter, and in late summer and fall, wandering males are out looking for mates. That last one is why sightings jump from August through October. A spider indoors is almost always hunting the insects that got in first, which means a spider problem is usually an insect problem you have not noticed yet.
Nearly every spider you will meet in a Maryland house is harmless. This guide covers the species you are likely to see, the two that homeowners worry about most, why spiders come inside, how to reduce them, and when it is worth calling a professional.
Which Spiders Are Common in Maryland Homes?
The University of Maryland Extension notes that many spiders wander indoors through and around windows, doors, and cracks, including jumping spiders, yellow house spiders, wolf spiders, and only rarely black widows. All of them are predators that feed on insects and other small pests.
| Spider | How to identify | Where you find it | Dangerous? |
|---|---|---|---|
| Common house spider | Small, yellowish brown with a rounded, mottled abdomen; builds tangled webs | Corners, windows, basements, garages | No |
| Wolf spider | Large, hairy, brown with stripes; runs on the ground and does not build a web | Basements, garages, ground-floor rooms, under doors | No; a bite is possible if handled but not medically serious |
| Cellar spider (daddy long-legs) | Tiny body on very long, thin legs; loose messy webs | Basements, crawl spaces, cellar ceilings | No |
| Jumping spider | Compact, often black with white or iridescent markings; large front eyes; hops | Windowsills, sunny walls, screens | No |
| Yellow sac spider | Pale yellow to greenish, small; hides in a silk sac in ceiling corners | Ceiling and wall corners, behind pictures | Bite can be painful but is not medically serious |
| Black widow | Shiny black with a red hourglass on the underside of the abdomen; glossy, almost plastic look | Woodpiles, sheds, crawl spaces, meter boxes; rarely inside living space | Yes; venomous, but bites are rare and seldom life-threatening with care |
| Brown recluse | Tan with a violin marking on the front body segment and an unmarked abdomen | Not established in Maryland; occasional stowaway in shipped items | Yes where it lives, but it is not a Maryland resident |
The two species below deserve a closer look, because one is real and uncommon, and the other is mostly a case of mistaken identity.
Black Widow: Present in Maryland, Rarely Indoors
The Maryland Department of Natural Resources states that the black widow is the only native Maryland spider that is dangerous to people. Both the northern and southern black widow live here. They favor dark, undisturbed places such as woodpiles, stone walls, sheds, crawl spaces, and the undersides of outdoor furniture, and they seldom set up in living areas.
Bites are rare. Black widows are shy, generally bite only when their web is disturbed or eggs are threatened, and sometimes deliver a dry bite with no venom, according to Maryland DNR. When venom is injected, symptoms can include sharp pain at the site, muscle cramping, sweating, and nausea. If you suspect a black widow bite, wash the area with soap and water, apply a cool compress, and seek medical care or call Poison Control at 1-800-222-1222, especially for children, older adults, or anyone with breathing trouble or severe pain.
Brown Recluse: Not Established in Maryland
This is the correction most homeowners need to hear. Brown recluse spiders are not native to Maryland or any of its neighboring states. Maryland DNR notes they turn up only on very rare occasions as stowaways in packages or moving boxes from the Midwest and Southwest, and that they are often misidentified. The University of Maryland Extension describes the one reliable field mark as a violin-shaped design on the front body segment, paired with a completely unmarked tan or brown abdomen. Other brown spiders of that size have stripes, spots, or bands instead.
Most Maryland recluse sightings are wolf spiders, house spiders, or sac spiders. Most suspected recluse bites are something else too. Maryland DNR points out that many wounds once blamed on brown recluses have turned out to be MRSA skin infections, which need medical treatment of their own. A spreading, painful sore that is not healing should be seen by a doctor, regardless of its cause.
Why Do Spiders Come Inside?
Spiders do not want to live with you. They end up indoors because your home offers what they are already looking for outside.
- Prey. Spiders follow food. Flies, ants, gnats, cockroaches, stink bugs, and other insects that get into your house are the dinner bell. A house with a healthy spider population usually has a steady supply of other pests feeding it.
- Harborage. Clutter, stored boxes, undisturbed corners, and gaps behind furniture give spiders cover to build webs or hide during the day. Basements and garages are ideal.
- Fall mating season. Many Maryland spiders mature in late summer, and males leave their webs to roam in search of females. That roaming is why you see more wolf spiders on the floor and more spiders in general from August through October. The house did not suddenly fill up; the residents are just on the move.
- Moisture. Damp basements and crawl spaces support the insects spiders eat, and some species, like cellar spiders, prefer humid spaces outright.
- Exterior lighting. Bright porch and floodlights draw night-flying insects to your doors and windows. Spiders build where the insects gather, and both slip inside when the door opens.
Spiders find their way in through the same routes as everything else: gaps under doors, torn screens, cracks around window frames, and openings where pipes and wires enter the house.
How Do You Reduce Spiders in Your Home?
Because spiders follow food and shelter, the most effective approach is to remove both. Killing individual spiders on sight does little if the conditions that attracted them stay the same.
- Control the other bugs first. Fewer flies, ants, and occasional invaders means fewer spiders. Fixing the insect problem is the spider treatment.
- Declutter storage areas. Swap cardboard for sealed plastic bins, get boxes off the floor, and leave space between stored items and walls so webs have nowhere to anchor unnoticed.
- Seal entry points. Caulk gaps around windows and utility penetrations, add door sweeps, and repair screens. This also blocks the insects spiders hunt.
- Remove webs and egg sacs regularly. Vacuum or brush down webs in corners, eaves, and window frames, and remove the small silk egg sacs before they hatch. This is the single most visible step and it interrupts the next generation.
- Fix moisture. Run a dehumidifier in damp basements and repair leaks. Drier spaces support fewer insects and fewer spiders.
- Adjust exterior lighting. Switch to warmer, yellow-toned bulbs and keep lights off when not needed so fewer insects gather at your doors.
Most of these steps overlap with sealing your home for fall, so pair this list with our fall pest-proofing checklist. Because spiders track the insects that arrive with cooler weather, our guide to common occasional invaders in Maryland homes explains what they are likely eating. For a room-by-room prevention walkthrough, see our companion post on how to keep spiders out of your home.
When Should You Call a Pest Control Pro?
Most spider situations are a vacuum-and-caulk job. Call a professional in these cases:
- You have found a black widow. If you have confirmed a black widow near living space, play areas, or where children and pets go, call for professional removal and an inspection of the harborage around them.
- Spiders keep coming back in numbers. A recurring spider population means a steady supply of insect prey. A technician can identify and treat the underlying pest problem rather than the symptoms.
- Egg sacs and webs return faster than you can clear them. That points to entry points and conditions you have not found.
Web removal is built into every Czar Guard plan: even the $39-per-month Czar Guard Basic includes spider web removal at each quarterly visit, along with exterior treatment for the insects that feed spiders and pest exclusion for up to one linear foot. You can identify what you are seeing in our pest library, or contact us for a free inspection. Pest Czar is a woman-owned, QualityPro and GreenPro-certified exterminator based in Towson serving the Baltimore metro.
FAQs
Why am I suddenly seeing more spiders in my house?
Late summer and fall is spider mating season in Maryland. Males leave their webs and roam looking for females, which puts more spiders on floors and walls from August through October. Cooler nights also push the insects spiders eat indoors, and the spiders follow.
Are there brown recluse spiders in Maryland?
No established population. Brown recluses are not native to Maryland or any neighboring state and appear only on rare occasions as stowaways in shipped items, according to the Maryland Department of Natural Resources. Most reported sightings are misidentified wolf, house, or sac spiders.
Which spiders in Maryland are actually dangerous?
The black widow is the only native Maryland spider dangerous to people. It is shiny black with a red hourglass on the underside, lives in undisturbed spots like woodpiles and sheds, and rarely comes indoors. Bites are uncommon and seldom life-threatening with medical care.
What should I do if I think a spider bit me?
Wash the area with soap and water, apply a cool compress, and watch it. Seek medical care or call Poison Control at 1-800-222-1222 for severe pain, muscle cramping, sweating, trouble breathing, or a sore that spreads or will not heal. Many wounds blamed on spiders turn out to be skin infections that need treatment.
Do house spiders bite?
Rarely. Most spiders that live in Maryland homes have fangs too small to puncture skin or venom that only affects insects. Bites usually happen only when a spider is trapped against skin, and they cause minor, short-lived redness and swelling.
Does a lot of spiders mean I have other pests?
Usually, yes. Spiders eat insects, so a steady spider population means a steady insect supply, whether that is flies, ants, gnats, stink bugs, or something else. Solving the insect problem is the most effective spider control.
What is the big hairy spider on my basement floor?
Most likely a wolf spider. They are large, brown, and striped, hunt on the ground rather than in a web, and wander indoors in fall. They look intimidating but are not medically significant.
Will spider spray get rid of spiders?
Not for long. Sprays kill spiders they contact but do nothing about the insects, clutter, moisture, and entry points that attracted them. Removing webs and egg sacs, sealing gaps, and controlling other pests works better and lasts longer.
Where do black widows hide around a Maryland home?
In dark, undisturbed places: woodpiles, stone walls, sheds, garages, crawl spaces, meter boxes, and under outdoor furniture and grill covers. Wear gloves when reaching into those spots, and shake out items stored outdoors before bringing them in.
Does Pest Czar remove spider webs?
Yes. Spider web removal is included in every Czar Guard plan, starting with Czar Guard Basic at $39 per month, along with quarterly exterior treatment for the insects spiders feed on and exclusion of entry points up to one linear foot.