08/07/2026
Open a window on a warm July afternoon and it can feel as if every fly in the neighbourhood dives straight into your kitchen. The instinct is to grab a spray, but there is a quieter way to shut the door on them.
Flies thrive in heat, and July is peak season because their eggs develop at high speed in warm, damp corners. Tackle the right spot for just two minutes around your sink and most of those uninvited guests never get started.
Why summer turns your kitchen into a fly magnet.
The housefly, Musca domestica, is the species most often buzzing around homes, drawn to any kind of food, rubbish, compost or even animal waste. It can detect smells from more than 6 km away, so a bin or drain never stays secret for long.
In warm weather this insect races through its life cycle. Around 25 to 30°C an egg can become an adult fly in about ten days, and a single female may lay between 500 and 1,000 eggs in just a few days.
Your home then does the rest. Kitchens stay warmer and more humid than the garden, with food scraps in bins, uncovered fruit, pet bowls and a constantly damp sink, so flies happily move indoors once summer gets going.
They do not just circle the fruit bowl. Many head straight for dark, sheltered spaces such as the back of cupboards, the underside of worktops and, crucially, the drain where warmth, moisture and food residue quietly come together.
The hidden fly nursery inside your sink drain
Every day crumbs, vegetable peelings and cloudy dishwater slip down the plughole, then cling to the inside of the pipes. Over time this builds into a thick, slimy film of organic matter that stays warm, wet and completely out of sight.
Flies, and drain flies in particular, breed in the moist, organic film that builds up inside drains and plugholes. Clean and disinfect drains regularly to remove a hidden breeding site and food source that's easy to overlook.
Drain flies and fruit flies love this kind of stagnant film, and houseflies will also exploit it if they can reach it. It provides constant food for larvae and a sheltered place for eggs to sit undisturbed until they hatch.
If your plughole smells slightly rotten, or you notice tiny flies hovering near the sink, that is often a sign the drain is already acting as a nursery. Flies are also drawn to the smell of food wafting up from the waste pipe.
The two-minute July routine to keep flies away
In summer you can stop this breeding ground forming with a simple ritual that takes roughly as long as boiling the kettle. It does not need chemicals from a spray can, which can linger on surfaces, just hot water and a simple cleaning product.
At least once a week in the warmer months, and daily if you already have flies, try this two minute drain clean:
Boil the kettle while you clear plates or wipe the worktop.
Squeeze washing up liquid, or sprinkle soda crystals, into the plughole and overflow.
Pour the boiling water down slowly so it scours the sides of the drain and trap.
The blast of boiling water softens and flushes away the greasy film where eggs and larvae sit, while the washing up liquid or soda crystals cut through fat so it cannot rebuild, especially if you repeat the routine every day.
Pair that with simple habits, such as keeping bins and food waste caddies shut, wiping worktops, rinsing plates instead of leaving them in the sink and occasionally washing the basin with white vinegar, and most flies lose interest.
Credit: Netmums
