German, American, Oriental and brown-banded cockroaches are the most frequently encountered roach pests within northeastern homes. The German species are the most common roach pest in the region, and they prefer to live solely within homes and buildings, and are rarely spotted outdoors. The brown-banded cockroach is the only other roach species in the US that dwells primarily indoors, but this species is much less abundant than the German species in all areas of the US. American and Oriental cockroaches dwell primarily outdoors, but they frequently invade homes where they remain for long periods of time, and they are both capable of reproducing indoors.

Both Oriental and American cockroaches congregate in sewer systems where they may travel into homes through plumbing. While Oriental cockroaches have been observed emerging from indoor drains, it is unlikely that they originated from sewers in these circumstances; instead, Oriental roaches probably moved into drains after invading homes from the outside. The Oriental cockroaches’ slow and sluggish movements, as well as their inability to scale smooth vertical surfaces, make traveling up sewer pipes difficult for the insect pests. However, this is not the case with the fast-moving American cockroach, which is thought to emerge from tub, basement and sink drains frequently after traveling through sewer plumbing. In fact, some residents of the northeast have taken to pouring Clorox down their drains in order to prevent American cockroaches from crawling indoors from their sewer living space.

According to Gary Braness, a pest control management consultant, both American and Oriental cockroaches have become abundant in sewers, and both travel through plumbing where they eventually emerge from indoor drains, but American cockroaches do this far more frequently than Oriental cockroaches. While Braness believes that Clorox may help to keep roaches out of plumbing, he also states that regularly pouring Clorox down drains can corrode pipes. Rather than using Clorox, Braness recommends placing a plugs or screen barriers over drains to prevent roaches from emerging. Also, the curved piping below sinks is known as a P-trap, and it holds water, making it hard for roaches to get past this section before climbing directly upwards and through drains. However, if water does not regularly run through sinks, the P-trap becomes dry, making it easier for roaches to pass the trap. This is why water should regularly run down sink drains.

Have you ever witnessed a large 2 inch roach emerge from an indoor drain?