Reviewed by Rob Greer, Certified Applicator, TDA License #0987052 · Last reviewed November 3, 2026.

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Signs You Have a Fly Problem

A fly that followed you in the back door is a fly that followed you in the back door. These are the signals that point to an active breeding source on or near your property.

A Sudden Burst of Large, Shiny Flies

Dozens of metallic green or blue flies appearing at one window or in one room, seemingly overnight. This almost always means something has died nearby, most often a rodent in a wall void, attic, or crawl space. The flies will stop when the source is gone, but the source needs to be found.

Tiny Flies Hovering Over Fruit or Trash

Small tan flies with red eyes circling the fruit bowl, the recycling bin, the wine rack, or the kitchen trash. Fruit flies breed in fermenting residue, and the source is often smaller than people expect: a single potato at the back of the pantry, a sticky mop head, or the film inside a garbage disposal.

Fuzzy, Moth-Like Flies Near Drains

Small, gray, heart-shaped flies resting on bathroom walls and shower tiles, flying weakly when disturbed. Drain flies breed in the organic film lining sinks, tub drains, floor drains, and overflow openings, and they’ll keep coming as long as that film is there.

Small Flies That Run Instead of Fly

Humpbacked little flies that skitter across counters and floors in quick, jerky bursts. These are usually phorid flies, and in Houston, persistent phorid activity with no obvious food source is a classic sign of a broken drain line under a slab foundation.

Fly Specks and Maggots

Clusters of tiny dark spots on light fixtures, window frames, and walls, which are fly droppings and regurgitation. Pale, wriggling larvae in trash cans, under bins, in pet areas, or migrating across a garage floor mean flies are breeding right there.

Painful Bites Around the Ankles Outdoors

A fly that looks like a house fly but bites hard, usually around the lower legs. That’s a stable fly, and it points to wet, decaying vegetation nearby: piled grass clippings, hay, compost, or manure, especially on properties with horses or livestock.

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Common Flies in the Houston Area

Correct identification drives the treatment plan, because each species breeds somewhere different. Our technicians identify what’s actually present before recommending anything. You can read more about other pests they may be looking for in our pest library.

House Fly (Musca domestica)

Health concern · The most common fly indoors

Gray, about a quarter inch long, with four dark stripes down the thorax. Breeds in garbage, pet waste, grass clippings, compost, and manure. House flies can’t chew, so they liquefy food with saliva and regurgitated fluid, and they land on waste and food alike. That habit is why they are associated with the spread of bacteria such as Salmonella and E. coli. Indoors, they loop around ceiling fixtures and rest on walls, cords, and window frames.

Stable Fly (Stomoxys calcitrans)

Painful biter · Common on acreage and horse properties

Looks almost exactly like a house fly but has a stiff, forward-pointing mouthpart for drawing blood, and both males and females bite. Breeds in wet, decaying plant material mixed with manure: old hay, soiled bedding, compost piles, and heaped grass clippings. A real concern around barns and pastures in Tomball, Magnolia, and the surrounding acreage, and a frequent nuisance at suburban pools and patios after a yard has been mowed and bagged clippings left to sit.

Blow Flies & Bottle Flies (Calliphoridae)

Health concern · Signals a dead animal or meat waste

Larger than house flies, with a shiny metallic green, blue, or bronze body and a loud buzz. Females can detect decay from a long way off and lay eggs on dead animals, meat scraps, and pet food. When they show up indoors in numbers, the usual cause is a rodent, bird, or squirrel that died inside a wall, attic, chimney, or crawl space. The odor and the flies are two symptoms of the same problem.

Flesh Flies (Sarcophagidae)

Health concern · Found with blow flies

Gray with a checkerboard pattern on the abdomen and bold stripes on the thorax, often with red eyes. They share breeding sites with blow flies and deposit live larvae rather than eggs, which shortens the timeline. Seeing them alongside bottle flies strengthens the case for a dead animal somewhere in the structure.

Fruit Flies (Drosophila species)

Nuisance · Kitchens, bars, and restaurants

Tiny tan flies with bright red eyes, drawn to fermentation. They breed in overripe produce, spilled juice and alcohol, recycling bins, mop buckets, garbage disposals, and the residue under refrigerator and bar equipment. The life cycle can run about a week in warm conditions, which is why traps alone rarely keep up with an active source.

Drain Flies (Moth Flies, Psychodidae)

Nuisance · Bathrooms, floor drains, and commercial kitchens

Small, fuzzy, gray flies with wide, rounded wings held roof-like over the body. Larvae live in the gelatinous film inside drains, overflow openings, grease traps, sewage areas, and the wet grout around rarely used showers. Pouring bleach down the drain usually won’t reach that film. It has to be physically scrubbed out and treated.

Phorid Flies (Humpbacked Flies)

Nuisance · Often points to a plumbing problem

Small, tan to dark brown, with a noticeably arched back and a habit of running across surfaces rather than taking off. They breed in nearly any decaying organic matter, including sewage. Houston’s expansive clay soils shift with drought and rain, and that movement cracks drain lines beneath slab foundations. Sewage-soaked soil under the house can produce phorid flies for months, emerging through gaps around plumbing, baseboards, and slab cracks. When we suspect this, we’ll tell you and recommend a plumber for a camera inspection or leak test.

Fungus Gnats (Sciaridae)

Harmless · Houseplants and overwatered beds

Delicate, dark, mosquito-like flies with long legs that hover around windows and potted plants. Larvae feed on fungi in damp soil and decaying roots. Easily confused with fruit flies, but the fix is completely different: letting the top inch or two of soil dry out and adjusting irrigation does more than any spray.

Black Soldier Fly (Hermetia illucens)

Harmless · Compost bins and trash cans

A slender, black, wasp-like fly with clear patches on the abdomen. It doesn’t bite, sting, or spread disease, and its larvae are actually used to break down food waste. They’re alarming when large, segmented larvae fill a compost bin or rolling trash can, but the solution is sanitation and lid management rather than treatment.

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Is It Really a Fly?

Several insects get called “flies” or “gnats,” and we’ll tell you honestly when it’s something else rather than treating something that doesn’t need it.

Midges and Crane Flies

Non-biting midges hatch in huge clouds near ponds, pools, and drainage, and crane flies bumble around porch lights in spring and fall. Both are often mistaken for mosquitoes or large flies. See our mosquito control page for more on telling them apart.

Biting Midges (No-See-Ums)

Nearly invisible biters that leave itchy clusters of welts around the head, neck, and arms at dusk, especially near water and marshy ground. They’re true flies, but they breed in wet soil and mud rather than garbage, so control looks very different.

Flying Ants and Termite Swarmers

Winged ants and termites emerge in large numbers around windows and light fixtures, usually after rain in spring. A swarm indoors is worth a closer look. We’ll identify what you’ve got before anything else happens.

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Gulf Coast Fly Calendar

Fly pressure in the Houston area tracks temperature, rainfall, and how quickly organic material breaks down. Knowing the cycle is what lets us treat ahead of the problem instead of reacting to it.

Season	What’s Happening	What We Focus On
January – February	Outdoor populations slow down, but never fully stop. Indoor breeders like drain flies, fruit flies, and phorid flies keep cycling in warm homes and restaurants. Rodents sheltering indoors raise the odds of a dead animal and a blow fly outbreak.	Drain and plumbing-related inspections, interior source work, rodent-related fly investigations, and exclusion repairs while activity is low.
March – May	Warming temperatures and spring rain restart outdoor breeding. Mowing season begins, compost and clippings pile up, and house fly and stable fly numbers start compounding.	The strategic window. Exterior sanitation assessment, perimeter and resting-surface treatment, bait placement, and screening and door repairs before summer.
June – August	Peak breeding. In summer heat, house flies can complete a generation in about a week. Trash carts and dumpster pads bake, blow flies are everywhere, and fruit flies explode in kitchens and bars.	Sustained source reduction, dumpster and waste-area treatment, baiting and trapping, restaurant and food-service programs, and patio and outdoor-living protection.
September – November	Still hot, often wet, and heavy with produce and outdoor events. Storms and flooding leave decaying debris. Cooler fronts begin pushing flies toward structures and into attics and wall voids.	Post-storm sanitation guidance, entry-point exclusion, interior fruit fly and drain work, and follow-up to confirm populations are down.
December	Cold fronts drive remaining adults indoors. Holiday cooking, extra produce, and overflowing trash create short-term indoor surges.	Kitchen and pantry source checks, drain maintenance, exclusion, and planning the spring preventive schedule.

If you only address flies when they’re in the kitchen, you’re always treating at the peak. Properties on a scheduled plan get the sources handled in spring, before the summer generations stack up.

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Our Fly Control Process

1. Inspection and Identification

We start by identifying the fly, because the species tells us where to look. Then we walk the interior and exterior, checking kitchens, pantries, drains, bathrooms, laundry and utility rooms, garages, attics and crawl spaces where accessible, trash and recycling areas, pet areas, compost, landscaping, screens, and doors. If the evidence points to a dead animal or a broken drain line, you hear about it that day.

2. Treatment Plan

Filth flies, small kitchen and drain flies, and biting flies each respond to different approaches, so the plan is matched to what we actually found. We explain what we’re using, where, and why, along with anything on the property that’s likely to keep working against the treatment.

3. Source Elimination and Treatment

The source comes first. We treat drain lines and organic buildup, address breeding material, and target the specific surfaces where adult flies rest and feed using baits, traps, and placed applications rather than broad fogging. Where the source requires another trade, such as a plumber for a slab leak or wildlife removal for a dead animal in a wall, we’ll tell you plainly.

4. Exclusion and Sanitation Recommendations

Treatment works better when the structure cooperates. We flag torn screens, failed door sweeps, gaps around plumbing and utility penetrations, uncovered vents, trash placed too close to doors, and drainage issues, and tell you which fixes will actually move the needle.

5. Follow-Up and Monitoring

Eggs and larvae already developing when we arrive will still emerge, so a single visit is rarely the whole job. We follow up to confirm the source is gone and the population is down, and ongoing plans keep the property protected through Houston’s long breeding season.

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Why Houston Chooses EnviRx

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Frequently Asked Questions About Fly Control

Why do I suddenly have so many flies in my house?

A sudden surge of large, shiny green or blue flies, especially in one room or at one window, usually means something has died nearby, most often a rodent in a wall, attic, or crawl space. Blow flies can find a carcass quickly and complete a generation in about a week in warm weather. A sudden surge of tiny flies usually points to a drain, overripe produce, or a plumbing problem. Identifying the fly tells us where to look.

How do I get rid of flies in my house for good?

Find and remove the breeding source. Every adult fly grew up as a larva in something moist and decaying, such as trash, drain film, fermenting produce, pet waste, or a dead animal. Traps and sprays only reduce the adults already flying. Lasting fly control combines source removal, targeted treatment of resting surfaces, and sealing the entry points that let flies inside.

How do I get rid of drain flies?

Drain flies breed in the organic film lining drains and overflow openings, so the film has to be physically scrubbed out with a drain brush and treated with a product designed to break down that buildup. Pouring bleach or boiling water down the drain usually passes straight through without removing the film. If drain flies persist after cleaning, the source may be a different drain, a dry trap, or a damaged line.

What are phorid flies, and why won’t they go away?

Phorid flies are small humpbacked flies that tend to run across surfaces rather than fly. They breed in decaying organic matter, including sewage. In Houston, persistent phorid flies with no obvious kitchen source often indicate a broken drain line under a slab foundation, which allows sewage to soak the soil beneath the house. When we suspect this, we recommend a licensed plumber for a camera inspection or leak test, since treatment alone can’t fix a broken pipe.

Are flies dangerous?

Most flies are a nuisance rather than a direct danger, but filth-breeding flies such as house flies and blow flies move between waste and food and are associated with the spread of disease-causing bacteria. Stable flies and horse flies deliver painful bites. Keeping flies away from food, food-prep surfaces, and people is the practical goal.

Is fly treatment safe around children and pets?

We select products and placement with households in mind, favoring source removal, baits, traps, and targeted application over broadcast spraying. Your technician will walk through any re-entry or drying guidance for the specific materials used before leaving. If you have reptiles, fish, backyard chickens, horses, beehives, or another sensitive situation, tell us when you schedule so we can plan around it.

Do fly traps, zappers, and fly strips work?

They catch some adults, but they don’t affect the larvae developing in the breeding source, so they rarely solve a real infestation. Bug zappers outdoors kill many harmless insects and can draw flies toward the area you’re trying to protect. Professionally placed insect light traps are useful in commercial kitchens as a monitoring and reduction tool, but they work best as one part of a source-focused plan.

Can you find the dead animal causing the flies?

We use fly activity, odor, and inspection to narrow down where the source is likely located, such as a specific wall void, attic area, or crawl space. When the source is accessible, we’ll discuss removal options. When it’s inside a finished wall or requires opening the structure, we’ll explain what that involves. The flies typically stop once the source is removed or fully dries out.

How quickly will I see results after fly treatment?

Most customers notice fewer adult flies within a few days once the source is removed and baits and treatments take effect. Eggs and larvae already developing may still emerge over the following week or two, which is what the follow-up visit is for. If flies persist after that, it usually means a second breeding source we’ll track down.

When is fly season in the Houston area?

Flies are active nearly year-round in Houston, but outdoor populations build through spring and peak from June through October, when heat shortens the life cycle to about a week. Indoor breeders like drain flies, fruit flies, and phorid flies stay active all winter in heated homes and restaurants. Spring is the strategic window for preventive treatment.

Will one treatment be enough?

For a single, clear-cut source like a forgotten bag of produce, sometimes. For most properties, an initial service plus follow-up is what it takes to catch the next emergence and confirm the source is gone. Homes and businesses that stay fly-free long-term are usually on a recurring plan that keeps sanitation, exclusion, and treatment maintained through Houston’s long breeding season.

Do you offer commercial and restaurant fly control?

Yes. We provide scheduled fly control programs for restaurants, bars, grocery stores, food processing, schools, medical facilities, and multi-unit properties, including floor drain and grease trap area work, insect light trap placement and monitoring, dumpster and dock treatment, exclusion recommendations, service documentation for health inspections and audits, and scheduling that stays out of the way of your operating hours.

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