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How do I know if my sewer line needs to be replaced?

Most homeowners don’t think much about their sewer line, and it’s understandable why. We’d rather not think about where our home’s wastewater goes, other than just “away.” Yet, given that sewer line problems are relatively common, homeowners should be familiar with what their sewer line is, how it works, and—perhaps most importantly—when they need sewer line replacement or repairs.

With this in mind, here’s a guide to your home’s sewer line and what you need to know about sewer line replacement. Let’s take a closer look.

What does a sewer line look like?

In this video, the team from This Old House uses an endoscopic camera to inspect the inside of a sewer line for damage.

How many years does a sewer line last?

Here’s a breakdown of the different types of home sewer lines, and how long each generally lasts:

Orangeburg Pipe: This type of pipe fell out of use in the 1970s. Made of wood pulp, they only last 30-50 years. For this reason, most homes featuring Orangeburg pipe sewer lines have already had to replace them.
Clay Sewer Lines: The most popular type of pipe material prior to the widespread introduction of PVC sewer lines. Clay pipes can last anywhere between 50 to 60 years. Homes built in the 1960s and 70s with clay sewer lines are nearing the point where they’ll need to be replaced.
PVC: Primarily used in homes from the 1980s onward, the rigid plastic of PVC is incredibly durable. PVC pipes should last about a century or longer.
Steel: This includes cast iron and other forms of metal piping. Steel isn’t commonly used for sewer lines due to its weight, tendency to rust, and its high upfront cost.
Concrete: Also a less common option, concrete sewer lines can last just as long as PVC and are an eco-friendly alternative. However, they can be delicate and prone to damage.

How long do PVC sewer lines last compared to clay ones?

In most cases, twice as long. Unless otherwise damaged by tree roots, PVC sewer lines should last for a hundred years or more—potentially outlasting the total lifespan of the home itself, depending on when your line was installed. Clay pipes, in contrast, last about 50-60 years. Still an extraordinarily long amount of time, but not an eternity: a home built in the 1970s with a clay sewer line is probably now approaching the day it will need to be replaced.

PVC pipes came into widespread use in the 1980s, so many homes with PVC sewer lines installed then should be good for many years to come. However, that doesn’t mean your PVC pipes are invulnerable. Even relatively “young” pipes can be damaged by shifting soil, thirsty tree roots, or interior clogs. Even if you’re decades away from having to replace your pipes, you should remain vigilant, care for your line, and be on the lookout for potential sewer line problems.

What does a broken sewer line smell like?

Here’s something you probably already could have guessed: sewer gas does not smell great. If you’re smelling something terrible, localized to your front yard or in the general vicinity of where the line runs, you’ve probably encountered a telltale sign of a sewer line leak. You’ll need to take action.

You’ll probably smell the problem before you see it, but you should also take a look at the earth above the line. If it’s water-soaked or soggy—even in the absence of recent rain—it’s a good sign that wastewater is escaping the line and saturating the surrounding soil. If you have a lawn above the line, look for grass that’s growing suspiciously well. It’s probably not your green thumb at work here: wastewater is a perfect fertilizer for grass, shrubs, and tree roots.

Does homeowners insurance cover sewer line replacement?

No. Most home insurance policies do not cover sewer line replacement, at least by default. You may be able to buy limited coverage add-ons to protect your property from water damage—such as that caused by a sewer line backup—but most insurers do not offer sewer line coverage as part of a home insurance policy. Even if yours does, you’ll need to weigh whether or not the added cost of coverage is worth it. We’ll discuss this below.

So, where does this leave you? If you’re planning ahead, you might be able to buy a separate sewer line insurance policy. However, such policies can be pricey. Whether or not you should buy one comes down to your individual home and, well, the sewer line itself.

Here are some factors that should steer you toward buying additional insurance coverage:

— If your home has a very old sewer line (think 1950 builds and earlier) that has not yet been replaced.
— If your home has heavy tree growth around it that puts your line at greater risk from tree roots.

When in doubt, talk to your plumbing contractor and get their opinion on the state of your sewer line. Then, speak with your financial advisor and see if this specific type of insurance is right for you.

What is the average cost to replace a main sewer line?

If your home insurance doesn’t cover sewer line repairs or sewer line replacement, you’re going to have to pay for your sewer line work out-of-pocket.

Ultimately, the average cost of sewer line replacement comes down to the methods used. Digging a trench to access the line is time-consuming and requires special equipment and permits. This approach is more expensive than trenchless sewer line replacement, which typically involves snaking a new line into the old one or pushing the old one out. If part of the sewer line runs underneath the slab, that will also increase your project overhead.

According to data collected by Angie’s List, most homeowners pay about $2,556 to replace a sewer main, with full sewer line replacement running people anywhere from $3,000 to $25,000. Why the wide range in costs? The longer the sewer line or the harder to reach it is, the more expensive the project.

If you are seeing signs of a sewer line leak or other problems, you need to call in a local plumber to help you sort things out. Look for plumbing contractors who offer sewer line repair and replacement services—they’ll be best-equipped to determine what’s going on and, in the event your line does need to be replaced, provide you with an upfront estimate for what the work might cost.