A home’s sewer line is something that homeowners never really ever think about, yet a blockage can spell disaster. Your sewer line is a lateral sewer pipe (often 4” PVC or cast iron) that connects the drains from your home's plumbing fixtures (toilets, bathtubs, sinks, and showers, etc.) to either a public sewer system or onsite septic system. In most cases, it relies only on gravity so it must be installed with a slight downward pitch away from your home. In some cases, an underground grinder pump in your yard helps the sewage reach the sewer system in the street.
The older the home, the increased possibility of hidden damage or blockage to this underground pipe. Tree roots sometimes will grow into underground sewer pipes which can lead to partial or complete blockage. It would be rare that a homeowner would ever have an inkling that their sewer line is partially blocked until they notice that the home’s sinks, toilets, and bathtubs all begin to exhibit slow draining. Few homes nowadays have basement floor drains connected to the sewer line. A slow drain at a single fixture likely indicates a partial clog at a specific fixture yet multiple slow draining fixtures indicate a bigger issue. Seeing an area of bright green grass in your yard when the rest of your lawn is dry and burnt out is a good sign of potential sewer line damage as well.
Sewer pipes are an out-of-sight, out-of-mind thing for most homeowners and home buyers. Most home buyers never even think of having the sewer line inspected as part of their home inspection and some may not even know this service is available. In many cases, sewer pipe damage or blockage can be quite expensive to repair since it often entails excavating the yard to access and replace part (or all) of the sewer pipe. Just to get a crew onsite and start digging to address underground sewer pipe issues often starts at $2,000 and goes up quickly from there.
As part of my inspections, I always recommend my clients consider having the underground sewer line inspected before closing, especially if the home is more than 10 years old. Cast iron and clay pipe was used in older sewer lines; cast iron was still often used into the 1970s in many areas. In some cases, you may only see PVC drain pipe inside your home, yet cast iron may still exist underground put of view. Most modern homes have plastic (PVC) sewer lines underground.
We use a sewer camera with a 120' long cable and an LED light on the end. As we push the camera down the drain pipe, we take video of the entire inspection to document what's inside. We've seen pipe breakages and blockages from tree roots as well as low spots in the sewer line where water accumulates preventing proper drainage. Sometimes, these low spots are due to heavy traffic on the ground above the line. We enter the sewer line either from an exterior (often in the front yard) or interior cleanout (often in the basement) although, in some rare cases, the roof mounted plumbing stack vent may be used. Plumbing standards require that a cleanout exist, at least, every 100' of sewer line.
Even if there are no trees presently in your yard currently, it doesn’t mean there may not still be underground roots hidden from view. Even when a tree is taken down, its root structure is still in the ground partially alive and still branching out in search of water. Roots can sense the water in a sewer pipe and can exhibit an unbelievable amount of force to push its way into a sewer pipe to reach that water, especially at pipe seams or breakages. So a tree that was taken down 20 years ago could still have the possibility of its tree roots clogging the sewer line.
Most homeowners are under the erroneous belief that the public sewer utility is responsible from their underground sewer line. This is not true.. homeowners are responsible for the underground sewer line from their home all the way out to the sewer utility's street connection. A public sewer connection is made up of 2 parts: the upper and lower laterals. The upper lateral is the portion of the sewer pipe that runs between your home and the property line. The lower lateral is the portion of the sewer pipe between your properly line and the public sewer line's connection often below the street. Homeowners are responsible for their entire sewer line.
I recommend this type of inspection be done with septic systems, too. Quite often, a septic inspection does not include inspection of the lateral drain pipe between the home and the septic tank but includes the tank and drain field only. What you don’t know about your underground sewer pipe can hurt you in terms of an expensive repair. In some cases, a blocked sewer pipe can also allow a backup into your home where appliances and stored items in your basement could get damaged by water and sewage and mold. Not something you ever want to come home to.
The inspection of underground plumbing (including your sewer drain line) is well outside the scope of a home inspection as defined by the Standard of Practice of ASHI (American Society of Home Inspectors). Luckily, some home inspectors and plumbers can perform a visual inspection of your underground sewer line to determine its interior condition. A sewer line inspection costs less than $250. A wise investment if you ask me. If your home is close to the street, this cost may be a bit lower whereas if there is a considerable distance between your home and the street, this cost may be higher. Having knowledge now can prevent headaches and large expenses later
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© 2019 Matthew Steger
Matthew Steger, owner/inspector of WIN Home Inspection, is a Certified Level 1 Infrared Thermographer, an ASHI Certified Inspector (ACI), and an electrical engineer. He also performs SewerScan inspections. He can be reached at: 717-361-9467 or email@example.com.
WIN Home Inspection has provided a wide array of home inspection services in the Lancaster, PA area since 2002. This article was authored by Matthew Steger, ACI - owner of WIN Home Inspection in Lancaster, PA. No article, or portion thereof, may be reproduced or copied without prior written consent of Matthew Steger.