How to eliminate small flies from drains?

How to eliminate small flies from drains?

Small flies from drains (drain flies) are a common problem in many households. Elimination requires systematic treatment of all drain openings — missing one may undo all efforts.

Check all drain openings

First, identify all potential breeding drain openings in your home:

• Bathroom floor drains — most common, highest numbers.
• Washbasin drainpipes (including overflow openings — many people don't know these can also breed flies).
• Kitchen sink drainpipes.
• Mop sink or utility sink drains.
• Washing machine drain hose connections.
• Balcony floor drains and air conditioner drain pipes.

Weekly boiling water flush

• Flush all drain openings with boiling water once a week.
• For overflow openings, insert a small brush to scrub, then flush with boiling water.
• Boiling water kills larvae and eggs.
• If you can disassemble the trap (U-bend) for cleaning, the effect is even better.

Apply insecticide

• Spray dinotefuran-containing household insecticide on the outer walls of all drain openings and surrounding areas.
• Also spray bathroom walls, corners, and under the sink.
• Adults that land on the treated surface die.
• Prevents newly emerged adults from flying out.

Persist for one month

The drain fly life cycle is about 2-3 weeks; larvae take time to mature and emerge. Treat weekly for one month to basically eliminate the flies. Thereafter, maintain with weekly boiling water flushes.