Why do I still have fleas after treating my dog?
Because the eggs already fell into the carpet and bedding, and the pupae can wait months to hatch. The pet treatment kills adults on the animal; the house has to be treated and vacuumed too.
Fleas (Cat Flea, Ctenocephalides felis)
Reviewed by William "Willy" Vizcarrondo, NYS Certified Pesticide Applicator (C1825832). Updated September 23, 2026.
Quick facts
The cat flea is the flea on Long Island dogs, cats, and the carpets and couches they sleep on. The reason flea problems drag on for weeks after the pet is treated is the life cycle: the eggs fall off the animal into the carpet, and the pupae can sit in a cocoon for months waiting for a host to walk by.
| Size | Adults no larger than 1/8 inch |
|---|---|
| Color | Reddish brown, wingless, flattened side to side, jump when disturbed |
| Look-alikes | Springtails (in damp areas, no biting), bed bugs (flat top to bottom, don't jump), carpet beetle larvae |
| Where you'll find it | On pets; in pet bedding, carpet, rugs, couch cushions, and cracks in floors where pets sleep; in yards where pets and wildlife rest |
| Active on Long Island | Worst July through October; year round indoors with pets |
| Danger level | Bites and itching, tapeworm in pets, allergic dermatitis in pets |
Long Island season
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
Flea pressure peaks in late summer and fall on Long Island, and a heated house keeps them breeding all winter once they're in.
How to identify it
Adult fleas are tiny, dark, and fast, and the surest way to find them is a fine-toothed flea comb on the pet. The other sign is flea dirt: small black specks in the pet's coat and bedding that turn reddish when wet on a paper towel, because it's dried blood (UC IPM).
Bites on people are usually around the ankles and lower legs in clusters. Springtails, which also jump, live in damp basements and don't bite.
Signs you have them
- A pet scratching and biting at itself, especially the rump and neck
- Flea dirt in the coat and on bedding
- Small jumping insects on the pet, the carpet, or your socks
- Bites on ankles
- Fleas appearing again a couple of weeks after treatment, which is the pupae emerging
Why it matters
A female lays about 20 to 50 eggs a day, and the eggs fall off the animal onto bedding and carpet (UC IPM). Larvae develop in the carpet in 8 to 15 days feeding on adult flea droppings, then spin cocoons, and fully developed fleas can wait in those cocoons for up to 12 months at cool temperatures for a host to trigger them (UC IPM).
That's why fleas keep emerging for about two weeks after a treatment: sprays don't kill pupae. Fleas also carry tapeworm to pets and cause flea allergy dermatitis.
Can I handle it myself?
A light case, often, if you treat the pet and the house together. The pet needs a vet-recommended spot-on or oral product. The house needs aggressive vacuuming of carpets, rugs, cushions, and along baseboards, which UC IPM calls very effective at killing larvae, plus hot-water washing of bedding.
Foggers mostly fail: total-release aerosols don't reach under furniture or into carpet and don't stop the next generation unless they contain an insect growth regulator like methoprene or pyriproxyfen (UC IPM). Call when fleas are still biting three weeks after the pet was treated, when there's no pet and you still have fleas, or when the infestation is in more than one room.
How Bobby Bugs treats it
A treatment of the carpets, cracks, and resting areas with an adulticide plus an insect growth regulator so the eggs and larvae can't mature, and guidance on the pet and the vacuuming schedule so the pupae emerging over the next two weeks die too. General insect treatment covers fleas.
Frequently asked questions
How long does it take to get rid of fleas?
Two to three weeks after a proper treatment, because pupae keep emerging for about two weeks and sprays don't kill them. Vacuuming daily during that stretch speeds it up.
I don't have a pet. Why do I have fleas?
A previous owner or tenant's pet, a wildlife animal like a raccoon or squirrel denning in the attic or crawl space, or stray cats resting under the deck. Fleas can wait in cocoons for up to a year for a host.
Do flea bombs work?
Rarely. Foggers don't reach under furniture or into carpet fibers, and without an insect growth regulator they don't stop the next generation. Targeted treatment plus vacuuming works.
Sources
Think you have fleas? Call (516) 509-6001 for a free written quote.