Short answer: if the bites cluster on your ankles and wrists and started fast after a pet or wild animal came around, fleas are the likely cause. If they showed up along your arms or shoulders after a night’s sleep and there’s no pet in the picture, bed bugs are more likely, especially after recent travel or a secondhand mattress, couch, or box spring came into the home.

How can you tell if it’s fleas or bed bugs?

Fleas live outdoors and in carpets, rugs, and pet bedding, so they bite while you’re up and moving, usually on your lower legs. Bed bugs live inside mattress seams, box springs, and furniture near where you sleep, and they feed at night, so the bites show up after you wake. The clearest giveaway is usually what else is going on in the house: a pet or recent wildlife activity points to fleas, while recent travel or a piece of used furniture points to bed bugs.

A quick way to check yourself before an inspection:

• Likely fleas: you have a pet, or wildlife has been active in the yard; bites cluster on ankles, wrists, or the neck; bites started fast, within a week or two; you notice bites while you’re up and moving.
• Likely bed bugs: you traveled recently or brought in a secondhand mattress, couch, or box spring; bites are along the arms or shoulders; you only notice them after waking up; small dark spotting shows up along mattress seams or the headboard.

Where fleas actually live in a Bay Area home

Fleas need a host to ride in on. A dog, a cat, or wildlife working the yard, such as rats, raccoons, or stray cats, are usually how they get inside in the first place. Once they’re in, they settle into carpets, rugs, upholstery, drapes, and anywhere a pet rests. Outdoors, look for shaded, damp corners: matted grass, dug-out spots along a fence line, or the area under a shed or deck. In the South Bay’s warm, dry inland stretch, San Jose, Milpitas, Morgan Hill, and Gilroy, the mix of agricultural land and backyard wildlife traffic keeps flea pressure high well into fall, so a yard that looks fine in October can still be seeding a problem indoors.

If your household matches that pattern, our flea treatment service starts with exactly this kind of walkthrough: pet bedding and high-traffic carpet indoors, shaded and sheltered ground outdoors.

Where bed bugs actually hide

Bed bugs don’t care about your yard or your microclimate. They travel in luggage, moving boxes, and used furniture, so a downtown San Francisco apartment carries the same risk as a single-family home in Livermore or Concord. Once inside, they cluster near mattress seams, box springs, headboards, and baseboards close to the bed, and a real infestation can spread to other rooms in the unit, not just the bedroom. When their environment gets disturbed, a bed bug either scatters to a new hiding spot or simply waits it out. It can survive roughly six months after a single feeding, which is part of why one visit rarely finishes the job.

For renters and homeowners near San Jose weighing whether it’s worth a professional look, bed bug treatment in San Jose starts with the same room-by-room inspection described below.

When the bites actually happen

Fleas bite at any hour, day or night. The pattern that stands out on an inspection is a fast spike: dozens of bites appearing over a week or two, concentrated on the wrists, ankles, and neck, and felt while the person is awake and moving through the house. Bed bugs work differently. They feed at night while you’re still, so most people notice the bites only after they wake up, not while it’s happening.

Neither pattern is a certainty on its own, which is why a technician still checks the physical evidence, carpet and pet areas for fleas, mattress seams and furniture for bed bugs, before recommending a plan.

Why late summer tips the odds toward both

Warm weather keeps flea hosts active. Pets are outside more, wildlife keeps working yards for food and water, and that combination holds flea pressure high from midsummer into September across the Bay Area, not just in one neighborhood. Bed bugs run on a different calendar entirely: they follow people, not the weather. Late summer brings a wave of travel returning home, plus a stretch when a lot of Bay Area leases turn over and secondhand furniture changes hands. Neither of those trends guarantees anything on its own, but they’re a large part of why late August calls about biting pests split fairly evenly between the two.

What a Banner inspection actually looks for

For a suspected flea problem, the technician walks the fabric surfaces indoors, carpets, upholstery, rugs, and pet resting spots, then checks the exterior for shaded ground and signs of wildlife traffic: matted grass, dug-out spots along a fence line, or a game trail leading under a shed. We’ll also ask when the bites started and whether anyone else in the household is being bitten, since a quick answer to those two questions does almost as much to sort fleas from bed bugs as the inspection itself. From there we lay out two options: a flea flushout on its own, which typically runs three visits over about two weeks, or that same flushout paired with general pest prevention around the exterior, which helps keep new fleas from riding back in.

For bed bugs, the process runs longer by design: an initial visit, then follow-up treatments at roughly two, four, and six weeks out. Mattress and box spring covers go on during the first visit and need to stay in place for at least a year. Monitors get placed to track where activity is still showing up, and it’s normal to see some bites or activity after the first treatment since the products used have a residual, transfer effect that keeps working as bed bugs come out of hiding. How much you cooperate with prep, bagging bedding, washing linens on high heat, clearing the space around the bed, genuinely changes how fast it resolves. Banner’s bed bug guarantee applies to single-family homes on a home protection plan.

DIY vs. calling a technician

A store-bought spray or a flea collar can knock down what you can see, but flea eggs sitting deep in carpet fiber or scattered across a yard are a different problem entirely, and they’re why the same complaint tends to come right back a few weeks later. Bed bugs are worse for DIY: they scatter when disturbed, and an incomplete treatment can push them into a neighboring room or, in an apartment building, a neighboring unit. Guessing wrong doesn’t just waste a weekend. It costs you the two or three weeks you spent treating the wrong pest while the real one keeps spreading through the house. Both are also common enough in common household pests in the Bay Area that a quick inspection is usually faster than weeks of guessing on your own.

One more sign worth watching for either way: if bites keep showing up after you’ve cleaned, vacuumed, and washed everything you can think of, that’s less about what you missed and more a reason to get a second set of eyes on the problem. Some pests take a series of visits to fully control, especially once they’ve had a few weeks to spread.

Bottom line

Sorting out fleas or bed bugs comes down to two questions: where do you find the evidence, and when do the bites actually happen. Fleas point outdoors and to pets; bed bugs point to the bed itself and to what recently came into the house. Ongoing quarterly service around the exterior helps keep fleas from establishing in the first place, and everyday habits that keep pests out go a long way toward keeping both off your radar. If you’ve already worked through the signs above and you’re still not sure, the next step is simple: call Banner and book an inspection. A local technician who knows your area will walk the property, identify what’s actually happening, and recommend a plan built around your specific home. No upsell. No pressure.

For a deeper walk through flea removal specifically, we’ve also written about how to get rid of fleas in your house, covering the full process step by step.