A month by month picture for Washington kitchens
June and July are usually quiet indoors. Windows are open, produce turns over quickly, and the 77F median summer high in Washington cities keeps kitchens below the temperature where development runs fastest. You may see the odd fly around a bin. August through October is the real season. University of Maryland Extension names late summer and fall as the national indoor peak, and that lines up with local harvest volume coming into houses: berries, plums, tomatoes, apples. Counters get crowded, fruit sits an extra few days, and bins fill with sweet rinsings. This is when a small source becomes a standing population. November through February looks like a mystery to most people. It is cold outside, so where are these coming from? The answer is always indoors. With winter lows near 35F, nothing survives outside, which narrows the search to your own drains, bins, pantry, and appliances. March through May is the cleanup window. If flies persist into spring, you have a permanent source such as a leaking drain line, and that is worth a professional look rather than another round of traps.
The bins nobody thinks to wash
Ask ten people with a fly problem when they last washed the inside of their recycling bin and most will admit never. That container is the single most reliable breeding site in a Washington home. Rinsed cans still carry a film of beer, cider, or juice, and in a state where average humidity sits near 73 percent, none of it evaporates. The residue pools in the bottom ribs of the bin and ferments. Food scraps containers are worse, because they are designed to hold exactly what fruit flies want. Even a well-managed one develops a sticky layer under the liner. The fix takes twenty minutes. Take every bin outside, wash with hot soapy water and a brush, pay attention to the underside of the lid and the rim where the liner folds over, then leave them open in the sun or a garage until fully dry. Wet is the operative word for this pest, so the drying step is not optional. Repeat weekly during fall and you remove a whole category of source from the house.
Fruit fly, drain fly, or phorid fly?
Three small flies show up in kitchens and only one responds to cleaning the fruit bowl. Sorting them takes about ten seconds of looking. a fruit fly is compact and tan with red eyes, roughly an eighth of an inch, and it hovers over fermenting material before landing on it. A drain fly is gray and fuzzy like a miniature moth, holds its wings tented over its back while resting flat on tile, and takes 21 to 27 days to develop in the biofilm coating a pipe. Because that cycle is three times longer, drain fly numbers look stable rather than growing, and scrubbing is what beats them. A phorid fly has a humped back and a distinctive habit of running across a surface rather than taking off. Its cycle runs 14 to 37 days in decaying matter, and indoors that usually means a cracked drain line, a sewer leak, or something dead in a wall. Phorid flies in a kitchen are a plumbing signal, not a housekeeping one, and treating them with traps wastes a month.
Renters and shared spaces in Washington apartments
If you rent in Seattle, Bellevue, Kent, or Renton, the first job is deciding whether the source is yours. Run a four-day test: refrigerate or remove all produce, take trash out nightly, wash your bins, scrub and cover your drains overnight. Keep counting flies in a trap. A clear drop means you found it. No change means the supply is coming from outside your walls. Shared sources are predictable. Trash rooms, compactor chutes, laundry room floor drains, and the utility closets where several units' pipes converge all stay warm and coated. Flies travel between units through the unsealed gaps around drain and supply lines under sinks, which are usually open holes hidden by a cabinet. Two things help. Seal those pipe gaps yourself with escutcheon plates or a bit of foam, which is cheap and reversible. Then send your building manager a written note describing your four-day test and its result. Specific evidence moves a Washington property manager to send a plumber far faster than a general complaint about bugs does.
How to read two quotes side by side
Ignore the headline price for a moment and compare four things. First, the number of visits and the gap between them. Because the cycle runs 8 to 10 days, a plan with a follow-up around day ten will catch insects that were still pupae on the first visit, and a single visit will not. Second, what the drain work actually is. Mechanical brushing plus a bacterial or enzyme product reaches the film where larvae live. A spray down the drain does not, and it is fair to ask a salesperson to explain how their product gets into that layer. Third, what they will tell you. A quote should end with a named breeding site or a plan to find one. Fourth, what they expect from you. A provider who says nothing about your produce, bins, and mops is either not being straight or plans to keep returning. Get the plan in writing, with visit dates and the sanitation steps assigned to you. That single page is the difference between hiring a fix and renting a pause.