When can I move in after "exterminating" fleas?

Hello Kate,

Sorry to hear about your situation. I’d suggest you ask the apartment’s leasing manager for a different apartment. Or at least get a discount on a couple months of rent, because this is going to be irritating for you and will cost you time/money. I’m guessing they collected the previous tenant’s security deposit, and I think some of that should go to you.

Are you referring to safety regarding the insecticides used? I’d recommend finding out what chemicals they sprayed, and then researching how long the premises should remain unoccupied.

Here’s the larger problem: The exterminator isn’t going to be able to kill all the fleas. At an absolute minimum, you’ll be dealing with a few adults emerging from the carpets for a couple weeks.

If they use a traditional insecticide (such as permethrin or pyrethrins), it’ll kill the already emerged adult fleas. But adult fleas only account for 1-5% of the total flea population. And, after the host in acquired, adult fleas live exclusively on the animal. Thus, adults aren’t the real issue.

Eggs, larvae, pupae, and pre-emerged adults make up 95-99% of the flea population. These stages live deep within carpets. Traditional insecticides won’t be able to kill a lot of these stages, because sprays and “bombs” can’t penetrate deep into the carpet matrix where they live. Thus, many will avoid the chemical treatments. Traditional insecticides also have a relatively short residual effect.

Insect growth regulators (IGR), such as pyriproxyfen or (s)-methoprene, are more effective at dealing with immature stages in carpets. These chemicals mimic natural insect hormones. They inhibit the biological triggers that lead to the next stage in development. Thus, they prevent the young fleas from pupating into adults. Eggs and larvae are most vulnerable. Those in the pupal and pre-emerged stages won’t be affected much.

Even after all the correct procedures are in place, some adult fleas will continue emerging from the carpets for up to 8 weeks. And you’ll likely be occasionally bitten, and left with itchy welts.

Without pets, the infestation won’t continue. The will fleas will go away on their own. No new eggs will be laid, as fleas can’t reproduce on human blood. But you’ll be dealing with the eggs that have already been laid and are now developing the carpeting.

Vacuuming daily with a beater-bar vacuum is the most effective way to speed up the eradication process. It’ll remove some of the fleas at all stages, and will force cocooned adults to emerge (which could otherwise remain quiescent for up 5 months while they wait to detect a host).

If an IGR wasn’t sprayed, it’s a good idea to purchase your own and spray it. Martin’s IGR comes in a suitable size for apartments. Most premise sprays also contain an IGR. Look for pyriproxyfen (Nylar) or (s)-methoprene (Precor) on the ingredient list. The nice thing about IGRs is that they remain residually active for 7 months indoors. Plus, they’re considered safer than traditional insecticides, because they specifically target the insect endocrine system.

To prevent bites, it’s a good idea to wear pants and socks indoors, and tuck the pant legs into the socks. Fleas can’t jump higher than a human ankle, and they can’t bite through clothing (unless the fabric is thin and the garments are tight-fitting, such as yoga pants). Also, don’t allow your bed sheets to hang low to the ground, or you may be giving fleas a route onto your bed to bite you while you sleep.

Hope this helps! Let me know if you have any follow-up questions.
Adam