How Long Do Septic Systems Last?

This is probably the most common question people have about septic systems, but it’s also nearly impossible to answer. There are a variety of factors that can either greatly increase or decrease the life of a septic system.

Everyone has probably heard horror stories about a friend or neighbor who had a septic system installed, only to have it leaking waste into their yard within a few years. On the flip side, there’s also always a few people proudly explaining that they still have the original septic tank they installed when they first built their house.

So what’s the cause of this huge difference? Was the early failure due to a low quality septic  tank? A bad installation? Maybe poor maintenance?

As it turns out, any one of those things could have been the problem.

Increasing the life of your septic tank…

The first step to a long-lasting septic system is having it installed well. This means you want to work with professionals with a proven track record of successful installations, and you also want to make sure the materials and components used in the system aren’t cheap or junky.

If your tank is already installed, there is still a lot you can do to increase the odds that your tank will keep working for decades. The number one thing you’ll want to do is perform proper maintenance.

And the most important maintenance you’ll do is having your tank cleaned and pumped regularly! If you don’t, you’re setting yourself up for all sorts of problems. One of the most severe is drainfield clogging. When a tank overflows, the drainfield (also called a leach field) can easily be clogged with material that should have been processed in the tank. When this happens, the entire field will need replaced. This can easily cost thousands of dollars.

Another thing related to maintenance is keeping a close eye on what enters your system. There are many household objects and chemicals that people think are safe, but they can actually wreak havoc in your tank. For a detailed look at what you should avoid flushing, check out our Don’t Flush That guide.

Beyond these factors, there are many things beyond your control that could decrease the life of your system. Things like soil acidity, tree roots, and natural disasters can all cause problems. It’s always a good idea to get a septic tank inspection done every few years or when you sell your home it’s probably required.

Average septic tank life expectancy…

Now that you understand that the lifespan of a septic system is highly variable, here are some averages that we’ve seen. Remember, yours could last longer or a lot shorter.

A well-maintained system with a concrete, plastic, or fiberglass tank should last several decades. Some even last 40+ years.

A steel tank will normally rust or corrode earlier than this, often around 20 years. Expect to replace them sooner, especially if you have acidic soil.

Drain/leach fields can last a long time as well, but they can fail extremely fast as well. Fields paired with poorly installed systems have failed in as little as 24 hours! If you take good care of the system, 20+ years isn’t out of the questions.

Hope this article has helped!