So how do you get ants in your home when you live in a desert, especially ants that are not indigenous to the desert? Well here's the answer. This is a potted plant that came from a nursery; its now dead but when the plant was purchased, the soil was very moist. In nurseries, all the plants are very close together and often times are grown in other locations, not in the desert.
Ant colonies establish inside the soil of the plant, then, the plants move and transplanted into your yard. They quickly establish on the tree that is growing and they'll harvest insects off the tree but the constant water drippers and the water source in the yard and in the desert emits water every couple of days to keep the ground and the soil underneath the plant wet.
As the population grows eventually they colony starts to spread out and move closer to the house as you can see here, living underneath patios and up against the house and pools. In time their population continues to grow with additional water and they make it inside the house and eventually your kitchen counter.