Is PVC Pipe Better Than Cast Iron Pipe?

One of the most common questions many people have when building a new home, building an addition or remodeling is if they should use PVC or cast iron pipe for their drain lines.  The answer depends upon many things, as each pipe type has both advantages, as well as disadvantages.  In addition, budget also pays a role in the decision.

In general, PVC drain lines are more economical and because of the materials used, grease and other buildups within the pipe are generally eliminated.  However, PVC wastewater drain systems are typically “noisier” than cast iron systems, meaning that the residents of the home will hear water running in the pipes when toilets are flushed and water is drained from tubs or sinks.  This is particularly true when on the first floor of two story home.  The drawbacks to cast iron drain lines is the potential for grease and other buildup in the pipe over time.  While more expensive, it is significantly “quieter” than PVC pipe.  In general, it is used in higher end residential applications, as well as in many condominium projects, where the reduction of “noise” is critical.

In many cases, the two products can be used together to provide an economical alternative, as well as a “quiet” plumbing solution.  The best mix is to use PVC under the slab and then transition to cast iron on the main vertical drain as well as the horizontal branch drains to the fixtures.   PVC is then used again on the vents.

A qualified plumbing contractor will be able to recommend the best solution for your project, as well as your budget.  Talk to your plumbing contractor about cast iron and PVC and see what they think!