Returning After a Long Trip Away

You have been away six weeks. The door opens onto warm still air, there is a smell from the bathroom, and something small crosses the kitchen floor while you are still holding a suitcase.

Almost everything people find on returning falls into three categories, and only one of them needs a professional. Working out which within the first hour saves a great deal of worry.

The smell is almost always dry traps

Every floor drain, shower gully and basin trap holds a small water seal, and in this climate that water evaporates in two to three weeks of disuse. The smell is sewer gas coming back through an open pipe, and it starts long before you get home.

Run every tap and shower for a minute, and pour water down every floor drain. The smell clears within a day. If it does not, the trap itself is damaged and that is a plumbing repair rather than anything to do with pests.

Large cockroaches in a bathroom are the same story

Those dry traps are open pipes into the building drainage, and American cockroaches use them. Individuals appearing in a bathroom or on a service balcony in the first days back are the drain problem seen from a different angle, and they usually stop within a week of the seals being restored.

Small pale-brown cockroaches in the kitchen are a genuinely different matter, because that species lives indoors and breeds indoors. Those are worth acting on rather than waiting out.

A technician sampling mosquito larvae from an air-conditioner drip tray at a home.

Fleas emerging on the day you arrive

This one surprises people every time, and it is worth understanding because the natural interpretation is wrong. If a household has a pet and there was a low-level flea population before the trip, the pupae accumulate during the empty weeks and wait. They emerge in response to warmth, vibration and carbon dioxide — that is, in response to somebody walking in.

So a family returns to what looks like a sudden severe infestation that appeared out of nothing. It did not appear while you were away; it was waiting, and you triggered it. It also means the treatment is a normal flea treatment rather than anything dramatic.

The first-hour list

Run every tap, shower and floor drain.
Open windows and get air moving before you unpack.
Check the kitchen cupboards, particularly rice, flour and anything opened.
Look in the bins, including the one on the balcony.
Empty and wipe balcony saucers and the air-conditioner tray.

A technician on a ladder treating an office ceiling.

Dry goods are the second most common finding

A bag of rice or flour left in a cupboard for six weeks in this humidity is a reliable producer of pantry moths and weevils. The sign is usually webbing in the corner of a cupboard or small moths in the kitchen at dusk rather than anything visible in the bag.

The response is to discard the affected packets, empty and vacuum the cupboard including the shelf-support holes, and wipe it out. Treatment is rarely needed and rarely helps, because the population is inside the food rather than on the surfaces.

Your own luggage

The other thing that arrives with you is the suitcase, which has been in hotels and on airport floors. Unpack it somewhere other than the bedroom if you can, put everything washable through a hot wash, and store the case open rather than closed. This is the one route by which bed bugs enter a private apartment, and it is entirely manageable at the moment of arrival.

When it is worth calling somebody

Call if you find small pale cockroaches in the kitchen, if there are fleas, if there is evidence of rodents, or if the smell persists after a day of running water. Do not call for one large cockroach in a bathroom in the first week back, because that is the drains and it will resolve itself once the seals are restored.

Common questions

Everything looks worse than when we left. Did something get in?

Usually not. What changed is that nothing was disturbed for weeks, so a small population had an uninterrupted run and is now at a size that is visible. That is a different problem from an invasion, and it is generally easier to resolve than it looks on the first evening.

Should I book a treatment before we come back?

Only if you left with a known problem, in which case treating an empty apartment is genuinely the best timing there is. Otherwise wait until you are home and can say what you are actually seeing, because a treatment aimed at nothing in particular is money spent for reassurance rather than for effect.

How long before things settle down?

For drain-related sightings, about a week after the traps are refilled. For fleas, a treatment plus two to three weeks, because pupae continue to hatch and the growth regulator has to catch them. For anything in the kitchen cupboards, immediately once the source packet is gone.