Why you need to have the sewer scoped when buying a home

Inspecting a home before your purchase is a critical piece of due diligence that you should do as a home buyer. One home system that is often overlooked is the sewer line. Normal home inspectors don’t examine it, since it is buried in the ground and it requires special camera equipment to inspect. The prudent home buyer will always have the sewer line inspected, regardless of the age of a home.

sewer lineA sewer backup is a potentially nasty and expensive event when you own a home.  Sewer line repair can also be extremely expensive, as it requires a lot of excavation and potentially street/sidewalk repairs. A cheap sewer line repair can cost $5000, and once you get in to the street, it can quickly reach a $10,000-$25,000 repair, making it one of the single most expensive repairs you could face during home ownership.

The side sewer line is the pipe that exits the home and joins up with the city sewer main, usually in the middle of the street. In Seattle, the oldest homes have sewer pipes that are made of clay. Sometime around the middle of the 20th century, this changed to concrete. In the late 70’s-early 80’s, builders began using plastic pipes (PVC or ABS). Clay and concrete pipes can be susceptible to cracks and tree root infiltration at the joints between section of pipes. Plastic pipes are glued together and impervious to roots. However, there can be issues with new plastic pipes as well. Cracks, pipe shifting, low spots and roots can all cause the sewer to backup into your home.

We have plenty of examples of sewer problems that we discovered in both old and new homes. The lesson here is to not necessarily trust what you are told about a sewer line, unless you have video from a recent sewer scope verifying its condition.

  • Our sellers had a sewer backup in 2003 on a house with clay pipes. They paid to have the entire line replaced and had no problems after that. They went to sell the home in 2012, and their buyer found that the last few feet of the line was still clay and was cracked. Our sellers got duped by their sewer contractor 8 years prior.
  • Our buyers were purchasing a 1911 home and were told by the seller that “we just did $10k of sewer work a couple of years ago, so it should be good.” Our own sewer scope revealed that indeed they did a lot of sewer repair, but it was only part of the line. The older parts of the line had large root infiltration and a big crack at the sewer main.
  • Our buyers purchased a home that was built in 2006. However, the builder reused the existing clay sewer line from 1911 to save costs. There were numerous breaks in the line that needed repair, even though the home itself was almost new.
  • Our buyers buying a 1960’s home in Kirkland were doubtful of issues with the sewer line, given it’s age. Our inspection found a root ball clogging the line. The seller cleared it out and the buyers didn’t keep up with the maintenance and had a sewer backup a few years later when the roots grew back.
  • We just sold a home built in 2012 that had ABS plastic lines. While there were no cracks or root infiltration, there was a section of the line that was angled upwards and not flowing properly. It was filled with rocks and sediment and was a sewer backup waiting to happen.
  • We’ve also found new houses with plastic lines that have been crushed by trucks driving over them, or coming apart when the contractor forgot to glue a joint.

The bottom line is that sewer lines of all ages can have potential issues. Personally I would never buy a house without scoping the sewer line. If you suspect the home has clay or concrete lines, a sewer scope is a must. Even with plastic lines, we’ve found plenty of issues that need to be addressed.  The couple hundred bucks you spend on a sewer scope inspection is well worth it to avoid costly and messy repairs in the future.