Soap water sugar vinegar.
Bug spray to kill drain flies.
On the night after you apply survivors spray pt cykick down all drains.
Add a few drops of dish soap to a bowl of water sugar and apple cider vinegar.
Dish soap contains borax which has insecticidal properties.
Set up a sugar and white vinegar trap for drain flies.
This will help you to clean hard to reach places where a brush cannot get.
Just remember to not use it for at least 24 hours after applying survivors.
How to kill drain flies.
It will kill both adult and larvae stages of drain flies and can be used as often as once a day.
Top best drain fly killers applying all sorts of liquid solutions provides a temporary effect but also has some advantages.
The thickness of the added soap will trap the flies in the water.
Take a cup and add cup white vinegar and cup sugar.
You could add 7 drops of dish soap with 2 cups of warm water and spray it directly over the drain flies to kill them instantly.