A house drain is a horizontal pipe that receives the contents of soil and waste pipes. Such contents include soil, also known as toilet waste, toilet water, and water from sinks and tubs. The house drain is usually located in the basement, cellar, or underground and connects to the house sewer just outside the foundation. They are usually made of some type of iron, but copper can also be used. When underground, it is usually made out of extra heavy cast iron in order to avoid the effects that chemical reactions and decomposition can have on wrought iron pipes.
There are two main types of pipes in a house drainage system: sanitary pipes and storm drains. Sanitary pipes are those that carry soil and other domestic wastes away from their sources. The purpose for storm drains is to carry excess rainwater away from the home. Sometimes these drains are separate—the storm drain carrying wastewater to streams, lakes, or other such place, and the sanitary drains carrying waste to the house drain, then to the house sewer, and eventually to the public sewer. There are times, however, when these drains are combined and the waste and rainwater goes to the sewer.
When a home is built, one of the first things to be laid is the house drain. This is done by first planning out where the drains should be. After the plan is finished, the drains are laid. Sometimes this is done section by section, but at other times, sections of the pipe are connected and then laid together. It is important for a professional to include clean-out points in the design of the house drains. Clean-out points are accessible sections in the house drain—no more than 50 feet apart (about 15.24 m)—where a person can clear the pipe in case it gets clogged.
House drains commonly pass through the foundation wall before connecting to the house sewer. The way this drain passes through the foundation is important because if it is not done properly, should the foundation settles, it could crush the house drain. For this reason, the drain usually passes through a hole in the foundation wall which allows for space to be all around the pipe. When constructing the hole, a capstone is placed over the hole in order to provide some strength and stability. This way, the home owners will not have a stinky problem on their hands if or when the foundation settles.