little black ants in kitchen and bathroom

Another species that could be in your bathroom could be Argentine ants (Linepithema humile) that have come from the outside and made their home in your walls or odorous house ants (Tapinoma sessile) and so on. Based on your description and location it could be any number of ants. Carpenter ants may be the most common bathroom occupants. They often nest behind tiles or bathroom walls. That's because damp areas make it easier for carpenter ants to create a desirable shelter. And, it can also provide them easy access to other areas of your house. Carpenter, pharaoh, odorous, and sugar