Why tiny ants have invaded your house, and what to do about it

Tanya Latty receives funding from the Australian Research Council and Agrifutures Australia. She has previously been funded by the City of Sydney and the Branco Weiss Society in Science Fellowship.

How to Get Rid of Ants in Your House and Yard

Here’s how to get rid of ants, including natural ant repellents, ant prevention tips and ant bait and killer spray recommendations.

Our editors and experts handpick every product we feature. We may earn a commission from your purchases.

How to Identify Ants

Start by identifying the type of ant in your house so you can find out how to get rid of ants, their nesting habits and have a better idea of where they’re living (they may be nesting outdoors). Take a close-up photo of the ant and send it to your local university extension service (enter your state’s name and “university extension service” into any online search engine). The extension service will tell you the type of ant you’re dealing with and where it nests. They may give you fact sheets about the ant species and maybe even some advice on getting rid of that particular ant species.

Image courtesy of Jeff Hahn, University of Minnesota

How to Find Ant Nests

Sometimes the solution to an ant problem is getting rid of their nest. If you’re dealing with carpenter ants, which can do structural damage to your house, it’s vital that you wipe them out ASAP. Finding the nest may not be easy and takes some detective work. Ants generally prefer damp areas, such as framing or flooring that’s soft and spongy from a plumbing or roof leak. How to get rid of ants begins by looking for areas with water damage. Attics, bathrooms and exterior walls are obvious candidates. Cut small holes in water-damaged walls to track down the ant nest. (You’re going to have to repair the walls anyway.) When you find the nest, spray it with an insecticide that contains bifenthrin, permethrin or deltamethrin (look on the label). Ortho’s Home Defense Max is one brand. Be sure to fix the water leak and replace damaged wood. If you can’t track down the nest, hire a pest control service. Pros spend about 80 percent of their time hunting down nests. Their fees start at about $150, but tough cases with multiple treatments can cost $400 or more.

Ant Removal: Determine the Best Ant Bait

When you see an ant, your first impulse is probably to step on it. But don’t. You’ll kill it, but for every ant you see, there may be hundreds more hiding in the house. The ones you see are scout ants, foraging for food to take back to the colony. Use these scouts to wipe out the entire colony. Prebait ants in areas you’ve previously seen them. Ants’ tastes change during the year. They usually prefer protein in the spring and sweets or fatty/oily foods in the summer. Set out sugar or honey, fried food and peanut butter, then see which food attracts ants. Use whichever food they prefer for bait and a DIY way to get rid of ants. Once you know what the ants like, buy and set out toxic ant bait that’s geared to their taste. Look on the bait package for words like “controls both sweet and grease eating ants.” Stop ants from coming in the house by using this ‘outdoor ant bait (Amazon)’ around your yard.

Ant Removal: Erase Ant Trails

Where you see one ant, you’re bound to see others. That’s because ants leave a scented trail that other ants follow. Sweeping or mopping isn’t enough to eliminate the scent. Instead, mix 1 part vinegar with 3 parts water in a spray bottle for a safe way to get rid of ants in the home, then spray wherever you’ve seen ants in the past. This will stop outdoor nesting ants that entered the house to forage for food (ants that come inside are not necessarily trying to establish a nest). Vinegar and water won’t stop ants that are already nesting indoors. You’ll need to kill them with ant bait.

Ant Removal: Wipe Out Ant Colonies

Once you’ve set out toxic ant bait, expect to see lots of ants (initially). That’s a good thing. It means more ants are taking the bait (which is toxic) back to the colony where they’ll share it with the rest of the ants, including the queen, and kill them. There might be thousands of ants back at the nest. Liquid bait is the best way to kill ants for many sweet-loving ants. Other ants prefer solid bait. If you still have ants in house after two weeks, replace the bait containers. If that doesn’t work, how to get rid of ants next means finding the nest.

Ants in house

Author

Disclosure statement

Tanya Latty receives funding from the Australian Research Council and Agrifutures Australia. She has previously been funded by the City of Sydney and the Branco Weiss Society in Science Fellowship.

Partners

University of Sydney provides funding as a member of The Conversation AU.

Languages

It’s nigh on impossible to calculate with accuracy how many ants are on Earth, but estimates put the number at about ten billion billion. And sometimes, it can feel like a good proportion of those ants are marching through our homes.

Ants usually come indoors in search of food or nesting habitat. Even small amounts of food, like pet food crumbs, can attract hordes of industrious ants.

Ants are one of Earth’s most successful animals, and comprise more than 13,000 species. They live almost everywhere except Antarctica, the high Arctic and a small number of islands.

Despite ants’ ubiquity, people can still be surprised, or even horrified, to see a line of ants crawling along their kitchen bench. So should you get out the insecticide, or learn to live with them?

What are ants doing in my house?

Ants are part of nature’s cleaning crew: they efficiently find and remove food left around the house. The problem is, sometimes humans don’t want their help.

You’ve probably noticed ants more commonly come indoors in summer – that’s largely because most insects are more active in the warmer months.

Ants occasionally come inside in search of water, particularly during dry periods. In this case you may see them in bathrooms or other humid parts of the house.

Heavy rains can also cause ant nests to flood and force them to relocate to nearby buildings, such as your house.

Masters of cooperation

Ants are social animals and live in colonies with hundreds, or even millions, of others. They have tiny brains – in many cases smaller than a grain of sand. So how are they so clever at getting into our homes and finding our food? Because they are masters of cooperation.

Consider the way some ants march in a line towards that drop of honey on your kitchen bench. When worker ants of some species find a tasty piece of food, they respond by placing a tiny droplet of pheromone on the ground. They continue to leave a trail of pheromones all the way back to the nest.

Only one ant needs to find the food and lay a trail. Once that happens, hundreds of others can follow the trail to the food source.

How do I get rid of ants?

The first step to dealing with ants in your house is ensuring they don’t have access to food. Seal all food in airtight containers, clean behind the fridge and in the toaster, do not leave pet food out longer than necessary, ensure your bins are tightly sealed, and generally make sure there is no food around to entice ants (I know, easier said than done).

If you’ve seen ants marching in a line, try wiping down the surface with vinegar or bleach to disrupt the chemical trail.

Prevent ants from entering your home in the first place by sealing up cracks and holes in walls. This will also prevent them from nesting inside wall cavities.

If all else fails, insecticidal baits can be used to control ant numbers. But before you take that route, ask yourself whether the ants are actually a problem (more on that later).

Insecticides may harm other insects

If your ant problem has got out of hand, contact a pest control professional rather than attempting to deploy a bug bomb or similar insect spray yourself.

DIY methods rarely work because ants mostly live in protected spaces (such as underground or in walls). You might kill a few worker ants, but probably won’t harm the colony.

If you (or a professional) do use insecticides, avoid using them outdoors and look for ones specifically designed for ants. Most insecticides are broad spectrum chemicals that can kill other types of insects. This includes insects beneficial in your home and garden, such as ladybirds, mantises and parasitoid wasps.

It may take a while for the ant colony to die, especially if it is large. Some species distribute themselves among several nests which makes them much harder to eradicate.

Ants fight back

In most ant species, the queen is the only individual who can produce new workers. So to destroy the colony, you need to kill the queen.

But some species, such as the rock ant (Temnothorax albipennis), have evolved an ingenious way to protect the queen and her larvae from poisoned food.

Some worker ants stay in the colony and receive new food from forager ants – storing the food in their abdomen and regurgitating it when their nestmates are hungry. Since these “storage ants” collect and mix food from many workers, they help ensure that incoming poisons are diluted before they reach the queen. They also act as poison testers: if the food is toxic, they die before they can pass it on to the queen.

We need ants

Remember that ants can be beneficial predators – I’ve seen ants attack and kill cockroach nymphs. Ants also play an important role in spreading the seeds of native plants, and of removing waste from our environment.

Ants are a normal and important part of our urban ecosystems. So if we want to protect our precious biodiversity, this may mean tolerating our tiny neighbours – even when they seem intent on taking over our kitchen or ruining our picnic.

No one wants ants ruining their food. But if you have a small number of ants wandering around the house, is that really a big deal?