Waste side plumbing is designed to move wastewater from the living space quickly and safely. If working properly, there should be no contact of wastewater or gases with the living area.
What Is It Made Of?
The two most common waste side plumbing material today are PVC, or polyvinyl chloride, and ABS, or acrylonitrile butadiene styrene. Both are durable, cheap, easy to use, and are therefore widely available. PVC is white and ABS is black. Drains are in 1 1/2″, 2″, 3″, and 4″ sizes for most residential applications. Schedule 40, which refers to the thickness of the PVC, is more durable than ABS. PVC installation is a two-step process, involving a purple primer. The primer is actually clear, but is colored purple so inspectors can verify that primer was used. Without primer, PVC will pull apart and fail prematurely.
Some older materials are copper (yes, there are actually some houses with copper drain pipes…worth a fortune!) and cast iron, with older homes having terra cotta (clay) pipes and Orangeburg pipe. The latter three materials were used underground, and are susceptible to root intrusion over time. Orangeburg pipe is a particular nuisance as many jurisdictions do not allow it to be replaced, but rather require that the line is completely replaced. Contrary to its name, Orangeburg pipe is nothing more than layers of black tar paper (produced in Orangeburg, NY up until the 1970′s.
Layout of Drain Pipes and Vents
In a normal house, smaller drain lines are connected to a larger, common line called a ‘stack’. The stack should extend all the way to the roof so the line is properly vented. Proper venting is vital to the proper function of a pipe as it allows water to move smoothly through the pipes. An improperly vented pipe is like holding your finger at the top of a straw filled with water.
The stack usually runs to the basement or into the slab and is connected to the main sewer. It is important that drain pipes running horizontally are sloped properly, based on code, so that the water does not run faster than the solids in the line, causing drain problems.
Cleanouts
Cleanouts are access points used to clear blockages. Generally, these are installed during the initial installation. However, in some cases, it is necessary to install a cleanout in existing plumbing to resolve a problem. These are usually straightforward installations.
How Drains Fail
Drains fail due to age, mechanical failure, or improper use. Older materials, such as cast iron, degrade over time and eventually fail to contain water. Mechanical failure can be caused by the shifting of the structure or ground, or through root intrusion. Improper use means putting things down the drain that don’t belong there, such as grease, tampons, and sometimes children’s toys! Remember, the drain is not a trash can.
So…Where Does It Go?
The answer to this question depends on where you live. If you live in a populated area, you are most likely connected to a centralized sewer system. Wastewater usually travels out the front of your house to the main sewer located under the street. From there, it will travel to a centralized treatment facility.
If you live in a less populated area, your wastewater most likely travels to a septic tank where the solids settle and the water flows through a sand mound, then to a drainfield.
For more information on septic tanks, visit our Onsite Wastewater page.