Drain and sewer cleaning is very similar. What is different is the type of waste these systems carry. Drains carry wastewater from your house to the municipal system. This is the water from the kitchen sink, bathtub, shower, and faucets. This line is smaller in diameter and tends to block more easily. Anything you pour down the kitchen or bathroom sink is a clogging hazard. The worst examples, however, include food waste and grease. The sewer line requires careful handling because it carries human waste from the toilets. The pipe has a larger circumference, and so is less likely to clog. It is, however, possible to block it if you flush the wrong things down the toilet. For example, if you flush sanitary products or diapers down the toilet, they will clog the system.