Dodging the “Sewer Repair Bullet” when Purchasing a Home

By: Patrick Hooper

This is an actual account of a main sewer line I recently inspected for a customer.

My client had an offer on a house pending the sewer inspection. It was built in the 1940’s and was being renovated to be sold. Given the age of the home, there was concern about the condition of the lateral line that connected to the city main. Now, the line did have serious issues and I recommended a replacement—but, that wasn’t the only problem.

The line that was inspected was what is referred to as a “hanging sewer”, also called a “hung sewer”. While most sewer and branch lines run under the foundation of a house, a hanging sewer accommodates branch lines that normally run above the foundation, usually overhead, and leaves the house horizontally through the wall above the foundation, instead of underneath it. (See below)

Basement Cleanout-Hanging Sewer

The good thing about a hanging sewer is that interior branch lines are above the surface of the foundation and don’t normally require excavation of the basement floor should a repair or replacement be required.

However, with this inspection, I noticed that in addition to the hanging sewer, there was a floor drain, as well as a floor clean out (see below). That told me that not only was sewage draining from the upper levels into the mainline, but there was also subsurface drain lines that were apparently below grade.

Floor Cleanout

Sewers are also referred to as “gravity lines,” which means they are not under pressure and rely on gravity/the downward angle of the pipe to drain water or waste. Now, if this house had sanitary infrastructure below the hanging sewer, how was that line draining into an above-grade mainline?

I’d seen this configuration once before. In that case, the underground line tied into the mainline out in the yard at a point where proper fall was able to be maintained. However, with this house, it was a whole different situation. When I couldn’t identify a tie-in where the subsurface line joined the main lateral, I performed a second inspection through the floor clean-out and discovered that the underground drain line led to a separate septic system in the backyard.

So what’s the big deal? Well, in the county where this house is located, the health department requires that any home on a septic system that is within 200 feet of the city sewer main must abandon and crush its septic tank, and run all sanitary infrastructures to the city sewer. In addition to the expense of abandoning the system, my customer would have an additional, more-expensive problem. Since the underground lines are below the level of the hanging sewer, the subsurface mainline would need to be redirected to an injection pit—which my client would also have to pay to install. An injection pit works basically like a sump pump for sewage. It pumps water and waste up to a higher elevation and into the lateral line. Injection systems, with the grinder pump, can cost up to $7,000 to have installed. That’s in addition to the costs associated with having the septic tank collapsed, which could be as much as $1,500.

When added to the expense of replacing the lateral line, you’re looking at more than $15,000 of additional costs just for the remediation of the sewer system.  Completely unexpected and unforeseen repairs that this buyer wouldn’t have known about if he hadn’t requested a pre-purchase sewer line inspection.

Talk about dodging a wallet-busting bullet…