Why do I suddenly have small flies in my bathroom?

Small, fuzzy, moth-shaped flies hovering around a sink, shower, or floor drain are almost always drain flies (moth flies). They lay eggs in the thin layer of organic gunk — hair, soap scum, biofilm — that builds up on the inside walls of drain pipes. Bathrooms used infrequently (guest baths, laundry room floor drains) are the most common source because that buildup never gets flushed out.

Will bleach or drain cleaner get rid of them?

Usually not for long. Bleach and most chemical drain cleaners run through the pipe too fast to break down the sticky biofilm layer that clings to the pipe walls, so the larvae underneath survive. This is why homeowners often say the flies "keep coming back" after pouring bleach down the drain repeatedly.

How does Bug & Bloom eliminate drain flies for good?

We use an enzymatic gel treatment specifically designed to break down the organic biofilm coating the inside of the pipe, removing the breeding material the larvae depend on — not just killing the adult flies you can see. We also inspect for slow drains or unused fixtures that are feeding the problem.

Pest Facts & FAQ Library

Drain Flies FAQ & Guide

Identify drain flies in the Phoenix East Valley, understand their habits, and discover how to manage them safely.

Drain Flies in Phoenix, Arizona

Overview

Drain flies (also called moth flies) are small, fuzzy, moth-like insects that breed in the gelatinous organic buildup inside slow-draining sinks, showers, and floor drains. They're one of the most common "where did these come from" calls we get in Mesa and Gilbert homes, especially in bathrooms that aren't used daily. At Bug & Bloom, we treat the source — the drain buildup — not just the flying adults.

Frequently Asked Questions

: Small, fuzzy, moth-shaped flies hovering around a sink, shower, or floor drain are almost always drain flies (moth flies). They lay eggs in the thin layer of organic gunk — hair, soap scum, biofilm — that builds up on the inside walls of drain pipes. Bathrooms used infrequently (guest baths, laundry room floor drains) are the most common source because that buildup never gets flushed out.
: Usually not for long. Bleach and most chemical drain cleaners run through the pipe too fast to break down the sticky biofilm layer that clings to the pipe walls, so the larvae underneath survive. This is why homeowners often say the flies "keep coming back" after pouring bleach down the drain repeatedly.
: We use an enzymatic gel treatment specifically designed to break down the organic biofilm coating the inside of the pipe, removing the breeding material the larvae depend on — not just killing the adult flies you can see. We also inspect for slow drains or unused fixtures that are feeding the problem.

Professional Ecosystem Pest Management

Eradicate Drain Flies Infestations Safely

Bug & Bloom uses smart, low-toxicity pest barriers, structural exclusion, and biological controls that eliminate drain flies at their root cause. No harsh chemical sprays inside your living areas. No required long-term contracts.

Call (480) 791-2847 Schedule Free Estimate

East Valley · Mesa · Gilbert · Chandler

Schedule Your Safe Drain Flies Treatment

We'll assess your property and recommend the right care plan — no pressure, no contracts.

Drain Flies FAQ & Guide

Overview

Frequently Asked Questions

Eradicate Drain Flies Infestations Safely

Schedule Your Safe Drain Flies Treatment

We value your privacy