Adult flies near a sink do not prove that drain is the source. Identify the fly and find wet organic breeding material before choosing control.

Inspect rarely used drains, overflows, traps, floor drains, condensate, leaks and wet organic residues without dismantling unsafe plumbing. Use monitoring approved by a professional to compare locations.

Source control may involve plumbing repair and physical cleaning of accessible organic film. Do not mix drain chemicals, combine bleach/acids/caustics or pour pesticide into drains unless the product and law expressly permit professional use.

Adult-fly sprays may reduce visible insects but leave larvae and breeding material, so activity returns.

FAQs

Do flies by a sink always come from that drain?

No. They may emerge from another drain, leak or organic source nearby.

Why can sprays fail?

They target adults rather than the wet breeding film and plumbing cause.

Suggested component

Use a Drain-Fly Source Map with a chemical-mixing hard stop.

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