Flies are more than a nuisance — they carry pathogens on their bodies and in their digestive systems, and a few species can establish serious indoor infestations in a matter of weeks. Different fly species require completely different control strategies: drain flies need drain cleaning, fruit flies need sanitation, and cluster flies need exterior exclusion. This hub brings together our guides to each species, plus general prevention and sanitation advice.
Common Fly Species Around Homes
Before you start treating, identify the fly you are dealing with. The location matters too — drain flies come out of drains, fruit flies hover around ripe food, and cluster flies appear at windows in fall. Species identification tells you where the breeding site is, which is where the real control effort needs to go.
Fruit Flies
Fruit flies are small, tan, red-eyed flies that hover around bananas, tomatoes, and any overripe produce. They breed in overripe fruit, in recycling bins, in trash cans, and — critically — in the slime layer inside drains and garbage disposals. A fruit fly problem that persists after you have thrown away all the fruit is probably breeding in a drain. Our guide on how to get rid of fruit flies walks through the full elimination process, and where fruit flies come from explains how they find their way indoors in the first place.
Drain Flies
Drain flies, also called moth flies, are small and fuzzy, with wings that look like tiny moth wings. They breed in the organic slime that builds up inside drains and sewer lines. Killing the adults with spray does nothing — the breeding site is the slime layer inside the drain pipe. Our guide on drain flies in the bathroom covers the treatment sequence, and if you are on septic, drain flies in a septic tank needs a slightly different approach. The best drain cleaners for pest control covers which enzyme treatments actually break down the slime.
Cluster Flies
Cluster flies are large, dark, and sluggish, and they appear indoors in fall in clusters around windows and in attics. They breed outdoors in earthworm burrows and only come inside to overwinter in wall voids and attics. Our guide on cluster flies on windows in late summer explains the exclusion strategy that actually works.
Gnats and No-See-Ums
Gnats, midges, and no-see-ums are tiny biting or nuisance flies that breed in damp soil, standing water, and overwatered houseplants. Indoor fungus gnats are a common houseplant problem; outdoor no-see-ums are a biting nuisance near water and damp vegetation. For the outdoor biters, the best no-see-ums repellent is the practical starting point, and how to get rid of gnats covers the indoor case.
Why Flies Matter
Flies are not just annoying. Because many species move freely between garbage, manure, and human food, they can mechanically transmit pathogens including Salmonella, E. coli, and Shigella. They also reproduce fast — a single female house fly can lay hundreds of eggs in her lifetime, and the full lifecycle from egg to adult can complete in a week or less in warm weather. That is why getting rid of flies requires removing the breeding site rather than just killing visible adults.
Controlling Fruit Flies
Fruit fly control requires finding every breeding site. Start by removing all overripe and rotting produce, then clean the inside of trash cans and recycling bins. If the problem continues after that, clean the drains and garbage disposal with an enzyme treatment. A simple DIY trap — vinegar and Dawn dish soap trap for fruit flies — can catch adults and give you a sense of whether the problem is shrinking.
Controlling Drain Flies
Drain fly control is entirely about cleaning the drains. Pouring bleach down the drain does not work — it kills the top layer of larvae but leaves the organic slime that they need to survive. Use an enzymatic drain cleaner that breaks down the organic material, or physically scrub the drain with a bottle brush. Follow up with an enzyme treatment once a month to prevent the slime from rebuilding.
Controlling Cluster Flies
Cluster fly control means blocking entry. Seal cracks around windows, doors, and utility penetrations. Repair or replace screens. Cover attic vents with fine mesh. The flies that are already inside can be vacuumed up — they are sluggish and easy to catch — but interior sprays only provide temporary relief. The most effective long-term strategy is exterior exclusion before the fall invasion begins.
Controlling Gnats and No-See-Ums
Indoor fungus gnats are controlled by letting houseplant soil dry out between waterings, using sticky yellow traps near pots, and applying a Bti-based soil drench. Outdoor no-see-ums are best managed with fine-mesh screens (18+ mesh per inch), picaridin or DEET repellents, and eliminating damp breeding habitat near the house.
Prevention: Sanitation and Exclusion
Most fly problems start with a sanitation or moisture issue. Keep trash bins sealed and wash them regularly. Do not leave food out uncovered. Fix leaky pipes and plumbing. Move compost bins away from the house. Screen windows and doors, and repair any torn screens. Reduce exterior lighting near entry doors, since many fly species are attracted to light at night.
When to Call a Professional
Call a professional if you cannot find the breeding site, if the infestation persists after sanitation and drain cleaning, if you suspect a sewer line break or a large breeding site under a slab, or if flies are appearing inside a wall void or attic. Cluster fly invasions in particular can be difficult to control without exterior exclusion work.
Last reviewed: November 2026.