Check near Water
Many different types of cockroaches thrive in areas of moisture, though others tend to stay away from damp environments. While you will not need to identify the type of cockroach you have in your home in most cases, checking near a source of water like a faucet, sink, or toilet fixture, particularly one that has been leaking or dripping is an excellent place to start. Even if you cannot see the cockroach nest, you will probably see cockroach droppings, which can help you to locate the nest.
Cockroach traps can help you get to kill cockroaches in your home and they can also help you to locate a cockroach nest. When you first notice cockroaches in your home, try putting cockroach traps in different areas where you see cockroaches, cockroach droppings or egg casings. Generally, the cockroach traps closest to nest will trap the most cockroaches, which can help you narrow down your search area. You should also leave cockroach traps down for several days, replacing them as necessary, even after you stop seeing cockroaches.
Cockroaches are often found near food sources and areas of heat and water like in the kitchen. Cockroach nests in the kitchen will likely be in tight spaces out of the way of foot traffic, like between the side of your stove and your kitchen cupboard. Use cockroach traps in these areas and check them with a flashlight to see if you can spot cockroach nests. Keep all food off counter tops and in tightly sealed containers if you have an infestation of cockroaches, and do not allow dishes to remain unwashed for long periods of time.