Generally speaking, you're usually responsible for drains inside the boundaries of your property, while the sewerage company is responsible for lateral drains, which are usually outside of property boundaries, and sewers.

Drainmen, on the other hand, specialize in cleaning and clearing clogged drains and sewer lines, using tools like augers and hydro-jetters to remove blockages. While some plumbers may also offer drain cleaning services, drainmen focus specifically on this aspect of plumbing maintenance and repair.