Cockroaches are some of the nastiest pests to deal with. These filthy, disease-carrying little critters can get all over your food and surfaces, leaving behind disgusting droppings, shell casings, and diarrhea in their wake.
Lucky, then, that you only spotted that one cockroach staking out your garbage can, right? Right?!
Asking the question I saw one cockroach should I be worried, the answer is YES! (spoiler alert—it’s rarely ever just one cockroach!). Here’s what you should know and do if you spot an unhygienic roach scavenger in the house.
What Does Seeing One Cockroach Mean?
There are two possibilities if you see a cockroach in the home.
The first one is that it’s a stray cockroach that unluckily ended up in your house after hitching a ride on your shopping bag or your firewood or some other object that you carried indoors.
It could be a scout, the sole survivor of its colony, or even just a cockroach given to solitude, especially if it’s a large cockroach that you spotted at night.
The second possibility is that this is the one cockroach you have seen but there are many more just hiding.
If it’s a baby roach that you saw, you’re too late—the roaches have been multiplying in your home.
Considering that cockroaches are good at reproducing, belong to colonies 99% of the time, and are nocturnal is bad news for you. It is likely that if you see one there will be a bunch more in the home.
But before you hit the panic button or start packing your bags to leave, take a breath. Even if you keep your house spic and span, roaches are very common pests and there is always a chance of a roach infestation. These infestations can be successfully dealt with if you’re willing to put in the time and effort.
However, acting immediately is necessary, a slow decision to act can only worsen the problem. You need to get a plan together on how to kill roaches in your home.
Remember a dead cockroach is a good thing because that means your plan has started working.
The Basics of Roach Infestations
There are three things you should know when it comes to the basics of roach infestations—the most common roaches, where to look for them, and why their house-hunting brought them to your place.
The Most Common Roaches
There are over 4,500 cockroach species (as if one wasn’t bad enough), but luckily, only 30 of these interact with human habitats. Luckily, only four of these are commonly found in the United States.
- American Cockroaches: This large roach is the most common species found in the country. Also known as water bugs, palmetto bugs, and flying water bugs, American roaches have fully developed wings that help them glide short distances. However, they prefer scurrying, ably assisted by their long legs.
American roaches especially love fermented food, which they seek out in commercial and personal spaces.

- German Roaches: Also found worldwide like their American counterparts, German cockroaches love the indoors, unlike most other roaches who prefer outdoor living conditions. Their preferred spots are warm and humid.
Though they have wings, these roaches prefer running. What makes them extra dangerous, though, is their incredibly fast rate of reproduction, which can make them a huge problem faster than you can say “huge problem”.

- Smokybrown Cockroaches: This outdoor cockroach most commonly appears in the southern United States. Smokybrowns love the high humidity —a necessity since they dry out fast.
Smokybrown roaches love settling down and hiding in one spot during the day and wandering out at night, when it’s cool, to forage for food and water. Even then, they keep their movements minimal to prevent water loss, which is why you’ll find them setting up camp very close to their food and water source.
Unlike the other roaches on the list, smokybrowns are excellent fliers.

- Oriental Cockroaches: This resilient species, prefers damp, cool spots instead of the warmth and humidity that the rest of the roach species seek out. They are so hardy that they can even outlast long, freezing months, which they survive by moving into crawl spaces and basements.
Oriental cockroaches love the filth more than their fellow roach species, which increases the risk of disease with this type of roach. Because of their love for trash, you’ll typically find them outdoors, in debris and garbage piles.

Where to Find Roach Infestations
Roaches commonly love warm, humid, dark, and damp spots both indoors and outdoors. Even if they prefer cool spots, like the Oriental cockroach, darkness plus close proximity to food and water is a must.
Indoors, you’ll find them in garages, in and under sinks, in pipes, cabinets, the basement, attics, bathrooms, the pantry, kitchen shelves, piles of stacked paper and cardboard, baseboards, closets, trash cans, drawers, and even in your electronics.
Outdoors, you’ll find these pests in mulch, wood, debris, leaf, compost piles, on trees, under logs, roof shingles, stones, and rocks.
What Drives Roaches Indoors
Cockroaches stray indoors for three main reasons—food, water, and shelter from the heat, cold, or rain. Sometimes, they may also foolishly wander indoors attracted by the lights in your house at night.
Messy kitchens with food crumbs all over the place, leaky pipes, uncovered leftovers, pet food, overflowing garbage cans, and unwashed dishes are all sources of food and water for these critters.
How Do Roaches Travel Indoors?
Roaches can make their way into your house through the following methods:
- Entering through openings around windows or doors
- Traveling through the pipes and plumbing
- Crawling through cracks in the foundation or walls
- Hitching a ride on suitcases, bags, containers, backpacks, etc.
Health Risks Associated with Roaches
Cockroaches carry a range of diseases on them from all the scavenging that they do. They spread these through their saliva, feces, and direct contact; eating and drinking contaminated food, touching contaminated stuff, and even inhaling contaminated air can trigger a whole set of health reactions.
Some of the bacteria that a single cockroach can carry include staphylococcus, salmonella, and streptococcus, which can lead to health issues such as:
- Typhoid Fever: A high fever caused by salmonella and contaminated food, characterized by headache, constipation/diarrhea, and belly pain.
- Diarrhea: Belly pain and frequent loose stools caused by contaminated food.
- Dysentery: An intestinal infection caused by contaminated food, resulting in bloody stools.
- Cholera: An infection that can cause diarrhea, dehydration, and even seizures and shock, in severe cases.
- Campylobacteriosis: A stomach infection that causes diarrhea.
- Gastroenteritis: An intestinal infection resulting in cramps, diarrhea, nausea, fever, and vomiting.
- Salmonellosis: Food poisoning that is caused by salmonella.
- Giardia: An intestinal infection characterized by bloating, cramps, diarrhea, and nausea.

Cockroaches, Allergies, and Asthma
Two other huge health issues that cockroaches can cause are asthma and allergic reactions.
Enzymes found in the shedding of their skin, roach droppings, saliva, and cockroach eggs can cause allergic reactions in people and even trigger asthma attacks, especially in children. These enzymes are disbursed through the air and instigate reactions when people inhale them.
Contact with roaches can also cause rashes. This makes cockroaches one of the most common indoor allergens.
What to Do If You See a Roach
If you see a roach, assume the worst, i.e., that it’s part of a larger colony. To confirm this, you can inspect your house, looking for signs such as:
- Finding fecal matter in your closets, drawers, kitchen, under the fridge, etc.
- Finding hiding spots (cockroaches hide during the day) by poking around in dark, damp, warm spots, such as your trash cans, underneath your bathroom and kitchen sink, your basement, areas around leaky pipes, spots where plumbing pipes penetrate the wall, etc.
- Looking for eggs/egg casings and cast-off skin (cockroaches shed during various stages of their development)
- Looking for brown smear marks that roaches leave behind on surfaces they traverse
- A foul smell (produced by a combination of pheromones and scavenging in filth)—roaches use this to communicate and it’s most noticeable when there are a large number of them
Once you’ve confirmed an infestation, you can tackle these on your own with solutions such as boric acid, DIY baits, gel traps, baits, insecticide sprays, dust, and granules.
If you’re unsure what to do or feel the infestation is extremely large, seek professional help. A professional can accurately assess the extent of the infestation and recommend the best course of action.
The products they use are also more powerful, quick, and efficient, and you can ask for a service guarantee and follow-up sessions for a set monthly price.
Prevent Future Infestations
This is a highly important step that will save you money and stress. Preventing future infestations is as simple as keeping your surroundings clean, sealing up entry points, and cutting out all sources of food and water.
- Keep Your Surroundings Clean: Keep both your indoor and outdoor spaces clean. Clean up spills and clear away food scraps, crumbs, and debris immediately, don’t let the trash accumulate.
Use tight-fitting lids on your trash cans and keep them in dry spots, don’t let dirty dishes accumulate in the sink, and vacuum thoroughly at least once a week to remove any stray crumbs or organic matter.
Outdoors, keep your yard clean, store firewood in a dry spot away from the house, remove leaves from your gutters, and clean up after your pets.
- Seal Entry Points: Caulk or foam spray any entry points in the walls and foundation. You also want to insulate all sweating pipes. Mend broken sewer lines and fix leaks so that the roaches can’t enter.
You can also use mesh screens on windows and doorways. You also want to make sure that the windows and doors fit well and leave no gaps. - Eliminate Food and Water Sources: By covering and safely storing leftovers and food in airtight containers, moving away pet food bowls, removing scraps, and properly sealing all plumbing and leaks, you take away the pests’ food and water sources. These are two of the three main reasons for roaches wandering into your space.
The Bottom Line
A cockroach infestation is disgusting, but more importantly, a health hazard. Dismissing even one cockroach can pave the way for a full-blown infestation that causes sicknesses such as typhoid, diarrhea, cholera, and gastroenteritis, among others.
If you prefer to tackle the problem on your own, make sure that you follow any usage instructions properly and take all necessary safety precautions, especially if you have pets or kids around.
Cockroaches can cause a world of pain and stress, but only if you let them. Practice preventative measures and if you suspect an infestation, make sure that you take immediate action with your cockroach problem. These small things can help keep your house roach-free while also improving your quality of life!