Most fly problems can be fixed without calling anyone. The catch is that
“flies” isn’t one problem — it’s at least four, and the fix that clears
fruit flies in two days does nothing for cluster flies in your loft.
This guide tells you how to identify which fly you’ve got, what actually
works for each, and the specific situations where DIY stops working.

This guide is written from 30 years of treating fly infestations
professionally, so it’s blunt about both sides: most fly problems don’t
need a pest controller, and a few genuinely do. You’ll know which is
which by the end.

fly removal london

First, work out which fly you have

This is the step most people skip, and it’s why most DIY attempts fail. Treatment depends entirely on the breeding source, and each species breeds somewhere different.

House flies — grey, around 6–7mm, fly in loose patterns around the room. They breed in rotting organic matter: bins, food waste, pet waste.

Fruit flies — tiny (3mm), tan-coloured, hover around
fruit bowls, sinks and wine glasses. They breed in fermenting fruit and
vegetables, and in the residue inside bottles and drains.

Drain flies — small, fuzzy, moth-like, sit on bathroom
and kitchen walls near plugholes. They breed in the organic film inside
drains and waste pipes.

Cluster flies — slightly larger than house flies,
sluggish, appear in numbers at windows in autumn and on warm winter
days. They don’t breed indoors at all — they enter through gaps to
hibernate in lofts and wall cavities.

Bluebottles and greenbottles — large, metallic, noisy. A
sudden influx usually means a dead rodent or bird in a wall cavity,
loft or chimney, because that’s where they lay eggs.

How to get rid of house flies

House flies are a sanitation problem before they’re a fly problem.
Killing the flies you can see does nothing if the breeding site is still
active — a female lays up to 500 eggs in her 30-day life, and the cycle
from egg to adult takes about a week in warm weather.

  • Find and remove the breeding source.
    Check kitchen bins, outdoor wheelie bins, compost caddies, pet food
    bowls and any pet waste in the garden. If you find maggots in or under a
    bin, that’s the source.

  • Clean the bin itself,
    not just the bag. Wash wheelie bins with disinfectant and keep lids
    fully closed. In summer, bag food waste tightly and empty kitchen bins
    daily.

  • Kill the adults.
    Old-fashioned fly paper and a swatter are genuinely effective for small
    numbers. A plug-in UV fly killer works in kitchens. Aerosol fly sprays
    knock down adults fast but do nothing about eggs and larvae — use them
    as a finisher, not a fix.

  • Stop re-entry. Fit fly screens to windows you keep open in summer, especially kitchen windows near bins.

    • Done properly, a house fly problem clears within a week. If flies keep
    returning at the same rate after you’ve cleaned every plausible source,
    the breeding site is somewhere you can’t see — under floorboards, in a
    cavity, or in a neighbouring property — and that’s when an inspection is
    worth it.

    How to get rid of fruit flies

    Fruit flies are the easiest to clear and the easiest to misdiagnose —
    people often fight “fruit flies” for weeks when they actually have drain
    flies. Check where they gather: fruit flies hover around food and
    drink; drain flies sit on walls near plugholes.

    2. Remove every fermenting food source. Ripe and overripe fruit into the fridge or bin. Rinse bottles and cans before recycling. Empty and clean the food caddy.
    4. Set a vinegar trap.
    6. A small bowl of apple cider vinegar with a drop of washing-up liquid
    8. (it breaks the surface tension so flies sink). Cover with cling film,
    10. poke a few holes. This clears adults within days.
    12. Clean the sink area.
    14. Fruit flies also breed in the gunk around plugholes and in seldom-used
    16. drains. Pour boiling water down, scrub the plughole, run the waste
    18. disposal if you have one.

    Fruit flies have a life cycle of about eight days, so if the food
    sources are gone, the problem dies out within a fortnight. If it
    doesn’t, you’re either missing a source (check under appliances for a
    rotten potato — it’s a classic) or you’ve got drain flies instead.

    How to get rid of drain flies

    Drain flies live off the biofilm inside your pipes, so traps and sprays are pointless — the breeding site is the drain itself.

  • Identify the breeding drain.
    Tape cling film, sticky side down, over each suspect plughole
    overnight. The drain with flies stuck to it in the morning is your
    culprit.

  • Clean the drain mechanically.
    A stiff drain brush down the plughole, then a proper enzyme or
    bacterial drain cleaner (gel formulations cling to pipe walls better
    than liquids). Boiling water alone won’t strip established biofilm.
    Repeat over several days.

  • Fix the moisture source.
    Drain flies in places with no obvious drain — under a bath, behind a
    kitchen unit — usually mean a leaking waste pipe creating a hidden
    breeding ground.

    • That last point is the honest limit of DIY. If cleaning every accessible
    drain doesn’t stop them, or they’re emerging where no drain exists,
    there’s a breach or leak in pipework you can’t reach. That needs a drain
    survey and targeted treatment — we do both as part of professional fly
    treatment for your home.

    How to get rid of cluster flies

    Cluster flies are the one on this list where DIY has a hard ceiling, so it’s worth being upfront about it.

    They spend summer outdoors, parasitising earthworms, then in autumn they
    squeeze through gaps around windows, eaves and roof tiles to hibernate
    in lofts and wall cavities — often in their hundreds, often returning to
    the same building every year because it carries the scent markers of
    previous generations.

    What works:



    • Vacuum up the sluggish flies you find at windows. Quick, chemical-free, fine for light numbers.Seal entry points
      — gaps around window frames, soffits, and vents (use insect mesh on
      vents, don’t block them). Do this in summer, before they arrive.

    What doesn’t: fly spray in the living room. You’ll kill
    the dozen you can see while hundreds remain dormant in the loft,
    emerging in batches every mild day all winter.

    A genuine loft infestation needs the hibernation site treated directly —
    typically with an insecticidal smoke generator or ULV treatment in the
    loft space, timed before or during the autumn entry period. That’s a
    professional job: the products aren’t available for amateur use and the
    timing matters. If you get cluster flies every year, book treatment for
    early autumn rather than fighting the same battle each winter.

    A sudden swarm of bluebottles?

    Twenty large, noisy flies appearing in one room over a day or two almost
    always means a carcass — usually a rodent or bird — in a wall void,
    loft or chimney. The flies are breeding in it. You can kill the adults,
    but more will emerge until the carcass is found and removed, which often
    means an inspection of voids you can’t access. This one is rarely worth
    fighting alone, particularly because a dead rodent can also mean a live
    rodent problem.

    Stopping flies coming back

  • Fit fly screens on windows you open regularly — the single best summer investment.

  • Keep bin lids closed, clean wheelie bins monthly in summer, and bag food waste tightly.

  • Clean plugholes and run water through seldom-used drains weekly.

  • Clear pet waste from the garden promptly.

  • Seal gaps around windows, eaves and pipework before autumn if you’ve had cluster flies before.

    • When to call a professional

    DIY clears most fly problems within one to two weeks. Call in help when:



    • Flies persist after you’ve eliminated every breeding source you can findDrain flies continue after thorough drain cleaning, or appear where no drain existsCluster flies infest your loft or return every autumnA bluebottle swarm suggests a carcass in an inaccessible voidThe
      problem is in a food business — fly infestations breach food hygiene
      regulations, and an EHO inspection won’t wait for your vinegar traps to
      work. Get commercial fly control with documented treatment reports
      instead.

    If you’re in London and any of the above applies, we can help — we’ve
    been treating fly infestations for over 30 years and provide pest
    control across London. Call 0800 999 3999 and we’ll tell you over the
    phone whether your problem actually needs us.

    Frequently asked questions

    Why are there suddenly so many flies in my house?

    A sudden influx usually means a new breeding source: an unemptied bin in warm weather, fermenting fruit, a blocked drain, or — with large bluebottles — a dead rodent or bird in a wall or loft. In autumn, sudden flies at windows are likely cluster flies entering to hibernate.

    What is the fastest way to get rid of flies?

    Remove the breeding source first — bins, rotting fruit, dirty drains — then kill the adults with fly paper, a vinegar trap (for fruit flies) or fly spray. Killing adults without removing the source gives you a fly-free day, not a fly-free house.

    Do vinegar traps really work for flies?

    Yes, for fruit flies specifically. Apple cider vinegar with a drop of washing-up liquid attracts and drowns them within days. It does little for house flies, drain flies or cluster flies, which aren’t attracted to fermenting fruit.

    How do I get rid of flies in my drains?

    Scrub the plughole with a drain brush, then use an enzyme or bacterial drain gel over several days to strip the biofilm drain flies breed in. Boiling water and bleach alone rarely shift an established problem. If flies persist, a leaking or breached waste pipe may be creating a hidden breeding site.

    Why do cluster flies come back every year?

    Cluster flies leave scent markers in the buildings where they hibernate, drawing them back to the same lofts and wall cavities each autumn. Sealing entry gaps helps, but recurring infestations usually need the hibernation site professionally treated in early autumn.

    When should I call pest control for flies?

    When flies persist after you’ve removed every breeding source you can find, when drain or cluster flies keep returning, when a bluebottle swarm suggests a carcass in a wall or loft, or when the problem is in a food business and compliance is at stake.