How to Replace Residential Sewer Lines

By Steve Sloane

Sewer lines are the pipes that take away all wastewater from your home every time a sink plug is opened or a toilet is flushed. Each water fixture has its own individual sewer pipeline that runs and connects into the home's main sewer line. This line in turn runs outside to either the city sewer or private septic tank. Sewer lines are generally made from PVC (polyvinyl chloride) or ABS (acrylonitrile butadiene styrene) hard plastic and come in different diameters to fit various water fixtures.

List of Items Needed

  • Black marker pen/carpenter's pencil
  • Handsaw
  • Utility knife
  • Tape measure
  • PVC/ABS sewer pipe
  • PVC primer
  • PVC/ABS couplings
  • PVC/ABS cement
  1. Mark the existing sewer line at the point where it will be replaced. Use a black marker pen for PVC, and a carpenter's pencil for black ABS. Make a straight perpendicular cut through the sewer pipe at the mark, using a handsaw or circular saw. From the point of the cut, measure and mark the unwanted section of the existing sewer pipe into removable lengths (3 or 4 feet) and saw through the sewer pipe at each mark. Remove the sections of sewer pipe.

  2. Scrape off burrs from the sawed end of the remaining sewer pipe by holding the blade of a utility knife against both the inside and outside end of the pipe at a 45-degree angle. Run the knife around the inside/outside perimeters of the pipe end. A rotary tool with a sanding or grinding attachment also works well for this task.

  3. Measure and mark the first new section of PVC/ABS sewer pipe, cutting it to length with the handsaw. Scrape off burrs. Brush PVC primer around the outside end of the existing PVC sewer pipe, as well as one outside end of the new PVC sewer pipe section (if working on an ABS sewer line, it needs no primer). Also prime the inside of a PVC coupling.

  4. Brush PVC cement onto both primed pipe ends, and the primed inside of the PVC coupling (for ABS, apply ABS cement to the existing pipe end, one end of the new ABS pipe section, and the inside of an ABS coupling). Push the coupling onto the existing pipe end, and the cemented end of the new pipe section into the other end of the coupling. Hold the pipe ends to the coupling for 15 seconds while the cement sets.

  5. Measure and cut a second section of new PVC/ABS pipe to length. Remove burrs. Prime one outside end of the second PVC pipe section, and the remaining end of the first new PVC pipe section. Also prime the inside of a second PVC coupling. Brush PVC cement onto all three primed areas (for ABS pipe, brush ABS cement onto one end of the second pipe section, the remaining end of the first new pipe section, and the inside of a second ABS coupling).

  6. Push the coupling onto the end of the first new pipe section, and the cemented end of the second pipe section into the other end of the coupling. Hold the pipe ends to the coupling for 15 seconds. Measure, cut and install all remaining pipe sections, installing them together with couplings, primer (for PVC) and cement, until the water fixture is reached.

Tips and Warnings

  • Both PVC and ABS sewer pipes come in diameters ranging from 1 1/2 to 4 inches. The couplings come in the same diameter range, and are available in straight, 30-, 45-, 60- and 90-degree angles.
  • Sinks, bathtubs, showers and washing machines hook up to the sewer line with P-traps. Toilets, however, connect to the sewer line with a closet flange (known also as as toilet flange).
  • When installing horizontal sections of sewer line, the line must be installed at a gradient for waste to move along the pipe. Contact your local city building department for the correct gradient in your area.

© Demand Media 2011