These are flies in the family Psychodidae. They are sometimes referred to as drain flies or moth flies. From Bugguide, "Moth flies: adults often found around sewage installations, in public washrooms, and bathrooms in homes, and are attracted to light; larvae live in organic sludge that forms on inner surfaces of drains and sewage pipes; pupae occur on the surface of the organic film that the larvae have been living in."

See this fact sheet from the University of Kentucky for information on management: https://entomology.ca.uky.edu/files/efpdf3/ef615.pdf.