Ants in the bathtub often indicate a nearby ant colony as the ants often find dark, humid places to nest. Bathrooms provide the ants with a preferred, moisture-rich environment. Also, bathtubs commonly attract carpenter ants, which may cause serious damage to a home's structure. Locating the ants and destroying the entire colony is the key to controlling these pests.
Identifying Carpenter Ants
Though all ants create a nuisance, especially when the bugs take up residence in your bathtub, carpenter ants provide an additional threat to the structure and safety of the space; therefore, you must properly identify carpenter ants. Carpenter ants range in size from 1/4-inch long to 1/2-inch long. Generally speaking, the body is black in color. Males have no wings, but winged females sometimes invade the home, especially in the spring.
Finding the Nest
For optimal control, you must locate the ant's nest, which is especially important with a carpenter ant invasion, because ants in the nest often dine upon the wood structure behind bathroom walls. A poorly caulked bathtub or water leak may attract ants to the wet wood. Use a flashlight to look through cracks and examine the areas where pipes protrude from the wall, suggests experts at the University of California Davis. Look under the home's crawl space for an ant colony. Lay food traps in the bathtub, and watch where the ants go with the food. Drops of diluted honey on masking tape also attracts carpenter ants.
Destroying the Nest
After following the ants until they disappear behind a wall, use a cordless drill to drill holes about 1/8-inch wide through the floorboards or baseboards. Drop boric acid powder into the holes. Treat the area on 3 to 6 feet on either side of the area where the ants were observed entering the wall. Also treat areas where pipes emerge from the wall in the bathroom. Sometimes ants observed in the home are nesting outside, so treating tree stumps, wood piles and the foundation may be necessary.
Chemical Control Options
While boric acid works well for treating carpenter ant nests, it is not a homeowner's only treatment option. Spray insecticides rated for ant control in a 3 to 6-foot wide path around the home's foundation to prevent outdoor ants from entering the home. Recommended products include products containing: carbaryl, propoxur, diazinon, chlorpyrifos pyrethrins and fenvalerate. Also treat windowsills, pipes, around doors and baseboards. Just keep away from food, children and pets.
For the homeowner concerned about using chemical products, pair home remedy treatments with boric acid treatment. Citrus and peppermint essential oils deter ants by forming an odor barrier the bugs will not cross. You can also sprinkle garlic powder or pepper around the border of the bathtub.