How Long Does A Sewer Line Last?

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Exposed old rusty water pipe in open trench

We all know the important role that a sewer line plays in our daily lives. Sewer lines remove sewage and wastewater from our home or business. If you have ever visited an outhouse, you can probably remember the odors, mess, and potential health risks associated with a static sewer system. Imagine that in your home or place of business! Time to get out! The smell alone can cause sickness.

Your first consideration is the health and well-being of you and your family at home. If you run a company, this means ensuring a healthy and safe environment for those who work and shop at your place of business.

At Bob Oates, issues of health and safety work hand-in-glove with our motto of “people helping people.” In this article, we’ll briefly cover how sewer lines function. We’ll then detail what broken sewer line symptoms look like and the factors that affect their lifespan. This is particularly significant given the PNW combination of beautiful trees and wet weather, and the historic nature of many Seattle-area neighborhoods.

Finally, we’ll provide you with measures you can take to check the health of your sewer system. And show you the steps necessary for professionally repairing or replacing a main sewer line.

Let’s get to it!

Understanding Sewer Line Function

Most home sewer lines (old and new) function on a gravity system of ¼” drop per foot of slope. This was and often still is all that safe waste removal needs for ideal drainage solution.

In commercial applications, a sewer system works exactly the same way a residential system would work (gravity). Both have varying degrees of negative health consequences when a sewage backup occurs.

For example, this could affect more than just the inhabitants of a workplace. (It might affect the public if food is being produced.) For a commercial or industrial business, the urgency surrounding sewer line repair or replacement is of the utmost importance.

Likewise, at home, things change once it’s obvious that replacing a sewer pipe in the basement is mandatory. You and your family may feel it necessary to avoid the house altogether while technicians arrive on site to quickly get the job done. Using the local gym or going to a hotel to use the facilities can get old real quick.

Last, we might reasonably assume that anything electric is more modern (and therefore more error-free) than non-electric devices. But the truth is that pumps and electricity can let you down in an emergency. Peace of mind is important — for our kitchens, our bathrooms, our businesses and in our busy lives — especially with our wet winters and abundant tree growth.

In other words, whenever possible, gravity systems are the reliable way to go. (Figuratively and literally!)

Seattle’s Sewer Line History

In some of our older neighborhoods like Queen Anne, Ballard, and West Seattle, and the cities of Tacoma and Everett, workers originally installed sewers using the open trench method of pipe laying. In fact, many of our sewer lines are over a century old! Digging a trench from the home to the street, connecting to the city sewer, was easy back in the day. This was long before all the development and growth our area has seen.

Sewer Pipes Then

Originally, molded concrete or clay pipe made most sewer pipes and fittings. The average size for residential and commercial applications was either 4” or 6” in diameter. It was common practice to combine two residential homes into one shared sewer. This method saved the contractor time, money, resources, and manpower.

Most pipes here in Seattle run almost 100’ to the city sewer, which can be 30’ in depth or more in some places. So it was to a contractor’s advantage to dig one long and usually very deep trench all the way to the city and make only one connection. Homeowners who have this type of system on their property can share the costs of replacing a main sewer line. (Perhaps with fingers crossed, since everyone always gets along with their neighbors, right?).

There was some logic to the way city planners did things way back when. They envisioned all utilities (water, sewer and electric) to be in the back alleyways we have in and around Seattle. That’s why most homes have their plumbing system in the rear of the house. When they later decided to put the utilities down the street, the plumbers had to reroute the sewer line to the front of the home. This was last minute change (at the time) from the urban planning and development department.

Sewer Pipes Now

This older method of installing sewer lines is in stark contrast to today’s construction standards and county regulations. For one, the tools and tech have changed over the decades — and certainly compared to a century ago. (Fun fact: A plumber or side sewer contractor will always run a new sewer line directly to the city main using the least amount of materials, saving time and money.)

Also, the explosion in growth across the region has meant more population density. And this means more people relying on sewer systems that some folks take for granted. (This is the “out of sight, out of mind” mentality, until the reality is neither).

It’s important to avoid this notion — not at all costs, but to keep costs under control. It is always preferable to get a few estimates from trusted professionals that can assess the current state of your system. Doing so is much more desirable than being forced to call in the pros for an emergency repair!

Signs of Damaged Sewer Pipes

Speaking of assessment, here at Bob Oates, our decades of experience in the Puget Sound means we can confidently make the following (general) statement about sewer line health: Unfortunately, most of our concrete and clay sewer pipes have outlived their life expectancy.

The greater Seattle, Everett and Tacoma areas primarily used concrete pipes, and the average life expectancy was 60 years.

So, with respect to the question, “how often do sewer lines need to be replaced?” — it depends on the type of pipe used and the age involved. Let’s now highlight some common signs of sewer line damage to look for as a home or business owner.

Common Symptoms

Damaged, collapsed or broken sewer line symptoms include the following:

  • Frequent backups involving tree roots
  • Sewer camera inspection showing cracks, breaks, or even broken pieces of pipe
  • Section of the yard or rockery is always damp or leaking

How Video Inspection Helps

Here, conducting a proper, regular inspection is key to maintaining healthy sewer systems, as well as determining exactly what the problem is and where it’s located. With today’s video cameras we can see cracks, breaks, “bellies” and offset or out of joint sections of sewer pipe.

In almost all of our older concrete pipes, many years of flushing and rainwater has dissolved the bottom of the pipe completely.

That’s right — our sewer systems also carry rainwater away from the property. This system in Seattle is called a combined system, meaning it treats storm and waste water the same.

(Our city of Seattle has plans in place to separate these systems as we write this blog. Just think of the mighty Colorado river and how it carved the Grand Canyon out of rock after millennia. In a smaller way this has happened right here in our hometown! Those concrete pipes didn’t stand a chance.)

Factors Affecting the Lifespan of Sewer Lines

There are a few different issues that can cause a compromised line. We’ll highlight the most common factors here, along with short explainers of what you can do to get things fixed and operational ASAP.

Tree Root Invasion

A very common cause is root intrusion through cracks and joints of the pipe. These occur because of tree roots searching for moisture and pushing their way through clay or concrete pipes. Over the years and decades, condensation builds up on the outside of sewer pipes, attracting roots to that moisture, and finally working their way in through a joint.

Left untreated, tree roots in pipes will eventually cause a collapse in the sewer line, completely blocking any flow.

If the sewer line has cracks, root intrusion and aggregate damage, there are many options for repair including sewer line replacement, trenchless sewer relining and sewer pipe bursting.

Sewer Line Belly

A belly or flat spot in the grade of the sewer line or a shift or offset where pipes connect is common. The natural shifting and settling of the Earth causes this occurrence.

Does a sewer line belly need to be replaced? Yes, or you will continue to get backups due to accumulation. Unfortunately, relining is not an option to repair a belly, but only the section that has the belly will need to be replaced.

And we’ve covered the age factor itself regarding clay or concrete sewer pipes — like we noted earlier, the average lifespan of a sewer line in our region is approximately 60 years, and our experience suggests repairing or replacing anything over 75 years old before an emergency occurs.

In sum, the factors affecting how often sewer lines need to be replaced depend on the current condition of the sewer line. Ideally you want to avoid an emergency and costly dig.

When Backups Become Critical

What constitutes an emergency? It’s when you can’t clear a backup due to a collapsed line, thereby forcing an emergency dig up job. (Remember our example at the top of the article, a “static system” — no thanks! — versus one that’s properly functioning?)

Having worked for more than 30 years helping our PNW neighbors keep their sewer lines flowing freely, we know a thing or two about prevention, maintenance, and expertly repairing or replacing a main sewer line.

If your sewer has a collapsed line you will need to have sewer line replacement or spot repair. But — good news! — in today’s world with our modern plastic, HDPE and schedule 80 pipe, most sewer lines will last for several generations, possibly more than a 100 years when installed properly.

Sewer Line Repair and Replacement

The bottom line? It’s wiser to have sewer repair done on your timeline — and not Mother Nature’s. (We contribute to it, of course, but she usually has the final say in deciding how long sewer pipes last.)

As we described above, many of our aging pipes have lasted 100 years or more — which was great for our forefathers, but not so much for us in the here and now, because we have inherited the problems associated with age and wear and tear.

Today, with annual cleanings and inspections we can be proactive instead of reactive when it comes to repairing or replacing our much-needed sewer lines. Whenever possible, we always recommend getting estimates on proposed work before you have an emergency repair done — simply because it’s going to be more expensive due to the nature of it being an emergency.

Time permitting, try to obtain two or three estimates to effectively compare reputation, materials, replacement options, etc., as well as costs and financing before making a final decision. And our position at Bob Oates is truly one of support here — call us first or last, we are the home of the second opinion! Free estimates gladly given along with free camera side sewer inspections from an accessible outside cleanout.

Wrapping Up

In conclusion, all sewer lines will need to be replaced at one time or another. You can expect the best results (and the longest life) with regular cleanings and inspections before you have a problem. Doing so could be the difference between a small repair or a complete replacement. No need to get caught unprepared!

We can help determine whether you need to replace the sewer pipes in your basement home or business. And there are several ways of repairing a sewer line or side sewer. One modern, popular method is trenchless pipe repair. it can solve the problem with little or no disruption to your normal routine — or your landscaping!

And always keep in mind that sewer repairs or replacements are investments in your home or business. They increase your property’s value and providing peace of mind at the same time.

We have solutions to all your sewer or drain cleaning, replacement, and relining needs. We are the experts in replacing a main sewer line, hands down — schedule your sewer inspection today!

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