How to Get Rid of Drain Flies (And Keep Them From Coming Back)

Drain flies vs fruit flies: Drain flies are small, moth-like, and fuzzy — they hang around sinks and showers. Fruit flies are smaller, shinier, and hover near produce. Different pest, different fix.

Step 1 — Find the breeding drain (tape test)

1. Before bed, place a strip of clear packing tape loosely over each suspect drain (don't seal it).
2. In the morning, check which tape caught flies — that's your breeding site.
3. Common culprits: bathroom sink, shower drain, rarely-used guest bathroom.

Step 2 — Scrub the slime out

This is the critical step. Drain flies breed in the gelatinous slime coating pipe walls — pouring things down won't remove it.

1. Use a bottle brush or pipe brush to scrub as far down as you can reach.
2. Pull out the gunk (it's unpleasant; that's the point).
3. For shower drains, remove the cover and scrub underneath it too.

Step 3 — Flush and treat

1. Pour a kettle of hot water down the drain.
2. Follow with an enzyme-based drain cleaner (eats organic slime; leave overnight).
3. Flush with hot water in the morning.

Step 4 — Break the cycle

Repeat the flush for 3–5 nights. Drain fly eggs hatch in ~2 days — you need to outlast one full generation.

<div class="safety"> <strong>🛑 Stop and call a pro if:</strong> <ul> <li>Flies persist after a week of treatment (possible broken pipe or septic issue)</li> <li>You find them coming from a floor drain connected to sewage</li> </ul> </div>

DIY vs pro cost

Printable checklist

• [ ] Tape test done — breeding drain identified
• [ ] Pipe walls scrubbed with brush
• [ ] Hot water flush
• [ ] Enzyme cleaner applied overnight
• [ ] Repeat 3–5 nights
• [ ] Unused drains run weekly (prevents re-infestation)