UK homes are being invaded by an increasing number of flies during the fourth heatwave of 2026. Rising temperatures accelerate fly egg hatching, and being cold-blooded, flies seek shady, moist spots like homes to lay eggs. A single female can lay up to 500 eggs in her 30-day lifetime, making control essential.
Keep on top of hygiene
Good hygiene stops fly breeding. Flies lay eggs on moist substances such as dirty dishes, open bin bags, or exposed food. Paul Blackhurst, head of technical academy at Rentokil Pest Control, says: 'To help prevent infestations, it’s important to dispose of food waste quickly, cover food compost caddies, and keep kitchen doors and windows screened properly or closed.' No1 Binman recommends keeping food waste containers out of direct sunlight: 'When it starts cooking and heating up, it attracts more flies because of the smell of it, so try and put in the shade. And if you want to get rid of some of them, you can put salt in your bin — it’ll also stop the maggots.'
Assess where they’re congregating
Flies thrive on moisture, so check areas with condensation or leaky taps. Removing moisture sources reduces their presence. Sophie Thorogood, technical training manager at Pest-Stop, suggests 'sealing gaps around windows, and fixing cracks in brickwork' alongside fly screens.
Use a vinegar solution
A DIY fly trap uses vinegar. Paul advises filling a shallow dish with an inch of vinegar (apple cider if possible), adding a tablespoon of sugar and a squirt of fruit-scented washing up liquid. Leave uncovered or cover with cling film and poke holes. Flies are attracted by the scent and cannot escape.
Buy an electric trap
Electric traps are the best shop-bought method. Indoor zappers from hardware stores or specialists like Rentokil should be placed four to six feet high and away from windows for best results.
Get advice on pesticides
Fly sprays can be toxic to pets or children if not used properly. Some fly species are resistant to certain pesticides. A pest control specialist can identify the specific issue and recommend treatment. For most flies, they are unhygienic but not severe; call professionals if swarms appear, as it may indicate a bigger problem.
