How Your Home’s Water Drain System Works

The drain system utilizes gravity as it carries solid waste and waste water from the house to the sewer.  Drainpipes point away from all fixtures at a predetermined angle to maximize waste efficiency.  If the angle is too steep, the water will exit too fast,  leaving behind heavy particles.  If the angle is not steep enough, the water will exit too slowly and may eventually back up into your sink, toilet, or bath tub.  The standard angle is 1/4 inch for every flat foot of pipe.

A soil stack compared to a waste stack.

A soil stack compared to a waste stack.

The soil stack does all the heavy lifting when it comes to waste removal.  The soil stack is a vertical section of 3 to 4 inch in diameter pipe that carries away waste from toilets and other fixtures.  The soil stack connects directly with the house’s main drain.  From the main drain, the waste flows into the sewer or septic tank.

Considering all waste drains will clog once in a while, cleanouts are placed in the drainpipes.  Ideally, there should be one cleanout for each flat section of drainpipe with cleanouts also in a main house trap. This is often times located outside in order to give sewer or septic access.  The cleanout is typically a 45 degree Y fitting or a 90 degree T fitting so that cleaning with a snake is easy.

HOW TO PREPARE FOR A TOILET, SINK, OR BATHTUB OVERFLOW EMERGENCY

Know where all fixture cleanouts are and have a plunger, Liquid Plumber, and or a small snake at your disposal.