Keep in mind that a slow drain could be an issue with a plumbing vent, which regulates the air pressure in the pipes. Plumbing vent issues should be handled by a plumber, but if you have debris caught in your drain pipes, then you should be able to fix it with a sink plunger or snaking the drain with a cable auger. You can find these at any hardware store.
Becoming a plumber is a two-pronged process that includes practical training and study. Traditionally, a hopeful plumber begins a four- or five-year apprenticeship program to receive technical education and complete the required hours of on-the-job training under a licensed professional. Plumbers who have successfully completed their apprenticeship are known as journeymen.
Sometimes you might need your sewer and drain lines inspected. For instance, if your sewage is backed up, then you probably want to determine what the cause is. In instances where we can't physically get to the problem to see what it is, we can use a sewer video camera to go down into your lines and take a video showing us what's the issue then. That way we'll know the appropriate way to deal with it.