Looking into your sink in the morning to see a spider looking back at you is not something you expect, and certainly not what you want to see. Spiders often find their way into a sink or tub, but they are not always able to make their way out. Spiders enter sinks for different reasons, and it is a myth that they climb in through the pipes. Spiders do not enter the sink through the pipe, but from above.
Looking for Water
Spiders need water to survive. They often drink water from droplets on plants or the ground or from dew gathered on their webs. If a thirsty spider is crawling around your house, it may find its source of water in your sink. Small water droplets may be left inside the sink from its last use. These droplets attract the spiders, which may be why they find their way into the basin.
Scavenging for Food
Spiders are carnivorous and eat live and sometimes already dead insects. Some large spiders are able to eat lizards and small birds. Spiders sometimes search for prey, and if they are inside your house, they may be scavenging for the insects. If an insect is in your sink, a spider will most likely enter your sink to attack its prey. It may simply enter your sink while searching for potential food.
Searching for Mates
Spiders mate in spring and summer. They often search for a mate, and sometimes female spiders release chemicals to attract male spiders. If a female spider happens to be in or near your sink while releasing these chemicals, male spiders will come her way. They may enter or stumble into the sink while searching for or courting the female spider, which sometimes involves dances.
Stuck in the Sink
Spiders are unable to climb the smooth surface of most sink basins. Their feet are unable to grip anything on the surface, causing them to be stuck in the sink. If a spider has entered your sink for any reason, it most likely can't get out, which is why it is still there when you happen to see it.
Remove spiders from the sink and put them outside. Spiders help keep bug populations under control, keeping other pesky bugs away from your home. Simply set a glass a jar or cup over the spider and slide cardboard or sturdy paper underneath. Flip the jar or cup over and hold the cardboard or paper on top, or put on a lid. Carry it outside and lay it on its side on the ground. Remove the top and allow the spider to exit.