There are many possible vulnerabilities in your house that could be allowing cockroaches to make their way inside. These could include: Cracks and crevices. Roaches feeding on organic material in your yard will often find cracks in your home to crawl through for shelter. Plumbing fixtures. Oriental cockroaches in particular are known to make their way through cracked pipes to find shelter. This is especially common in multi-family housing complexes. Groceries. German and brown-banded roaches are often brought into peoples’ homes unknowingly after trips to the grocery store. Sewers or drains. American cockroaches are known to live in sewer systems in residential areas.