Cockroach Control in Morgan Hill, CA

Local Context

When Morgan Hill Irrigation Shuts Off in Fall, Whatever Lived in the Valve Box Comes Inside

Start with the species, because they mean different things. American cockroaches (Periplaneta americana) are the large reddish-brown ones, and in Morgan Hill they live outdoors year-round in irrigation valve boxes, water meter vaults, sewer and storm lines, and the damp mulch of a heavily landscaped lot. They come inside one or two at a time — up a floor drain, through a dry trap in a guest bath nobody uses, or under a garage door with a worn seal.

Water is the trigger. This valley gets essentially no rain from April into November, so outdoor roaches concentrate in the few dependably wet places, which on a large irrigated Morgan Hill lot are the valve boxes and the drip zones. When irrigation is cut back in October and the ground finally dries, that population moves, and the closest permanent moisture is the plumbing inside the house. It reads to a homeowner as an infestation and it is really a migration.

German cockroaches are a different problem and never a verdict on housekeeping. Blattella germanica lives indoors permanently, breeds quickly, and arrives inside something carried in — a delivery carton, a used appliance, secondhand furniture, a case of restaurant supplies. In the mixed-use buildings and apartments along Monterey Road it then moves between units through shared plumbing chases, which is why treating one unit on its own tends not to hold.