u/Clapcheeks69

I had my whole house repiped recently, including replacing a cast iron drain. Now I have drain flies, mainly from the kitchen sink. I don't cook and never put food in the sink or down the drain. I've used boiling water, and Invade Bio Drain Gel. When using the gel I let it sit undisturbed for days. Still have flies.

I've lived in the house for two years and remodeled the bathroom and kitchen, so mostly new stuff. Never had this problem until I got new pipes.