Monday, February 15, 2010

When clay soil and cast iron pipes meet

My house is among the many houses built in East Austin in the late 1950s (and maybe other places) that used a unique type of iron pipes for the sewer pipes leading from the house to the city sewer mains in the street. Typically houses are built with cast iron pipes, but this iron was centrifugally spun to create the hole in the center instead of in a cast (info courtesy of our plumber). Somehow this makes them more vulnerable (not sure of the details). Anyways, over time, the chemicals we pour down our drain can damage any iron pipes. Also, in the case of our house, if you don't have enough slope in your pipes, standing water can them rust away. It is possible that over time, corrosion of your pipes will accumulate such that you get a hole in your pipe, and instead of waste water being delivered to your city sewer system, you are also watering the ground underneath your house with chemicals (shampoo, household cleaners etc.) and other gross human goo. Another reason these pipes may be seeing their last days is that they reside in clay soil. Clay soil retains water very well, and we all know what happens when you mix water and iron: rust! Anyways, it is 2010 and this is a picture of the pipes that are now being excavated from our soil not a moment too soon.


  1. So, is your answer to replace the cast iron pipes with PVC pipes? Do you replace the clay soil with less corrosive dirt. Isn't all dirt corrosive?

  2. This is a very interesting question. Some soils are more corrosive than others, and I hope to elaborate on this in a future post. Hold tight!