Although they may be found all over the house, the German cockroach is usually found in the kitchen and bathroom. The optimum indoor harborage areas for German cockroaches are in areas where protection, food and moisture are available. German cockroaches can initially infiltrate a structure when infested grocery bags are brought inside. Inspect groceries for cockroaches before storing. Keep grocery bags in outside storage areas.
The German cockroach in particular is immune to many toxins, making them one of the most difficult to remove. Practice good sanitation. Habitat reduction, along with vacuuming, surveillance, and baiting program, and some sealing of cracks can usually reduce or eliminate a cockroach problem. The reduction of moisture sources, such as leaking pipes, is also helpful.