How Long Do Septic Systems Last

The role of a septic system is to provide an on-site, efficient, and environmentally friendly method for treating and disposing of household wastewater in areas without access to a centralized sewer system. The system is made up of several components, including a septic tank, drainfield, and distribution box.

A septic system is a significant cost to a homeowner and, naturally, you would like to know how long a septic system lasts, or what is the life of a septic system. In this article we go into the major components of a septic system, the different materials they can be constructed from and how to do proper maintenance to ensure the life of your septic is long.

A well maintained septic system will last 40-50+ years. During this time you will need to perform regular maintenance and the addition of a septic tank additive can significantly reduce the stress on the system and the number of times it needs to be pumped.


What are the components of a septic system

Conventional Septic System

The septic system describes the entire system that takes the waste from your home, processes it and distributes sanitised, clean water onto your property. Many people don’t know the different components. It is important to know what type of septic system you have, as components may vary.


A septic system is typically made up of the following components:

  • Septic Tank: A buried, water-tight container usually made of concrete, fiberglass, or polyethylene. Its job is to hold the wastewater long enough to allow solids to settle down to the bottom forming while the oil and grease floats to the top as scum.
  • Drainfield: A shallow, covered excavation made in unsaturated soil where the liquid wastewater (effluent) from the septic tank is discharged. The effluent is then absorbed into the soil, where bacteria filter and digest contaminants.
  • Exit Pipe: Carries wastewater from the home to the septic tank and vents noxious gases up.
  • Distribution Box and Network of Pipes: Part of the drainfield, consisting of one or more distributor boxes and a network of pipes buried in relatively shallow soil.
  • Effluent Filter: In new septic installations, effluent filters are required at the outlet of the septic tank to prevent solids discharge.
  • Inlet and Outlet Pipes: The septic tank has an inlet pipe where the wastewater from the home enters the tank and an outlet pipe where the partially treated liquid (effluent) exits the tank.


A septic system is designed to provide primary wastewater treatment by separating and treating the waste in a natural way before it is absorbed into the soil

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Septic tanks

The septic tank’s primary function is to separate liquid and solid waste, allowing solids to settle at the bottom and scum to float at the top. The treated liquid, or effluent, then flows into the drainfield, where it is further treated as it percolates through the soil. This process helps to remove contaminants and protect human and environmental health.

Septic tanks are commonly constructed from the following materials:

  • Concrete septic tanks: A concrete septic tank is a sturdy and traditional material used for septic tanks. However, it can be prone to cracking due to settling, earthquakes, and pressure from above. Additionally, erosion from sewage gases can affect the concrete over time.
  • Fiberglass septic tanks: Fiberglass-reinforced plastic is another material used in the construction of septic tanks. It is resistant to corrosion and provides a durable option for septic tank construction.
  • Plastic septic tanks: Polyethylene or polypropylene resin is used to manufacture plastic septic tanks. These tanks are resistant to corrosion and offer a lightweight alternative to concrete and fiberglass tanks
  • Steel septic tanks: Many states or counties do not allow steel septic tanks to be installed as they have a shorter lifespan than other septic tank material and can corode leading to contamination and the need for septic tank replacement.



How long do concrete septic tanks last?

A well-designed and well-built concrete septic tank can last for about 40+ years. There are usually no external variables that will decrease the lifespan of a concrete septic tank if the tank was built out of high-quality concrete. However, it’s important to note that the actual lifespan of a septic tank can be influenced by factors such as the quality of the concrete, water table, soil acidity, and maintenance techniques and environmental factors like types of trees near the concrete tank or if you drive over the concrete septic tanks.


How long do fiberglass septic tanks last?

Fiberglass septic tanks can last anywhere from 20 to 30 years, depending on various factors such as construction methods, soil conditions, and the materials used during manufacturing. Proper construction and anchoring are essential to ensuring the longevity of a fiberglass septic tank. While fiberglass and plastic septic tanks can last for decades, it’s important to consider factors such as installation depth and soil conditions, as they can impact the tank’s lifespan


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How long do steel septic tanks last?

A steel septic tank can have a relatively short lifespan compared to other materials like a concrete tank. Typically a steel tank will last between 15 to 20 years due to the tendency of steel to rust and corrode over time. Regular inspections are important to catch any rusting early and prevent irreparable damage.


How long do plastic septic tanks last?

plastic septic tanks have an average lifespan of around 30 years, making them a durable choice for wastewater management. Factors such as proper installation, soil conditions, and maintenance can influence the actual lifespan of a plastic septic tank


How to prolong the life of your septic tank

To prolong the life of a septic tank, the following maintenance tasks are recommended:

  1. Regular Pumping: Set up a regular effluent pump cleaning and tank pumping schedule. Having the tank pumped is the most critical maintenance task. A septic tank should be pumped about once every 2 to 5 years to prevent the buildup of solid waste, which can diminish the tank’s holding capacity and cause overflow.
  2. Proper Waste Disposal: Avoid disposing of non-biodegradable items such as feminine products, tissues, and paper towels in the septic system, as they can increase the risk of clogging. Additionally, avoid pouring fats, oils, and grease down the drain, as they can contribute to clogging and reduce the efficiency of the system.
  3. Water Conservation: Excessive water use can overwhelm the drainfield, so it’s important to avoid using more water than necessary, especially if the septic tank is relatively small.
  4. Use of Bacteria Additives: Use cleaners that are labeled as safe for septic systems to avoid killing the bacteria in the tank. Bacteria additives can also be used to help maintain the bacterial balance in the system.
  5. Regular Inspections: Inspect the septic tank for cracks and leaks, and ensure that the baffles are not missing, broken, or deteriorated. It’s also important to check for visible wear and tear, such as crumbly concrete and rust-colored streaks, which are signs of a structural problem that needs addressing.


Septic Drain Field

new construction material used by septic contractor

A septic drain field, also known as a leach field, is an essential part of a septic system that serves to eliminate and manage waste and impurities from the water released by the septic tank. It works by dispersing the treated liquid, or effluent, into the soil through a network of perforated pipes or chambers. The soil then acts as a natural filter, removing contaminants and impurities from the effluent as it percolates through the ground. This process helps prevent waste runoff, protects against the ingestion of wastewater by animals, and ensures that the septic tank does not overflow. Proper care and maintenance, such as avoiding the introduction of solids, fats, oils, and grease into the system, are essential to preserving the functionality and longevity of the drain field.


How to prolong the life of your septic drain field

Many of the points that prolong your septic tank will also prolong the life of your drain field and the entire septic system. The key thing to remember is that the drain field can get clogged easily from fat, hair, synthetic items. So it is important to ensure your tank is pumped correctly and you have a quality septic tank treatment to reduce many of the organic waste clogging your leach field.


Additional areas of maintenance specific to your leach field are:

  1. Proper Waste Disposal: Refrain from flushing non-biodegradable items, fats, oils, grease, chemicals, and other harmful substances down the drain, as they can clog the drain field and damage the system.
  2. Vegetative Cover: Maintain a vegetative cover over the drain field to reduce soil erosion and absorb excess moisture. Avoid planting deep-rooted trees or building structures over the drain field, as they can damage the system.
  3. Regular Inspections: Schedule regular inspections to identify and address potential issues before they escalate. Inspections can help prevent costly repairs and ensure the longevity of the drain field.


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Frequently Asked Questions


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What are the signs of a failing septic system?

Signs of a failing septic system or reasons septic systems fail include:

  • Sewage Backup: Human waste or wastewater backing up into sinks, drains, or the toilet inside the home.
  • Slow Drains: Drains draining very slowly or stopping draining.
  • Odors: Nasty odors near the drainfield or inside the home.
  • Wet, Soggy Areas: Wet, soggy areas above or near the drainfield, and spongy bright green grass over the area.
  • Gurgling Sounds: Gurgling or bubbling sounds in the plumbing system.

These signs can indicate a failing septic system, which can result from inappropriate design, poor maintenance, or other issues. Regular maintenance, proper operation, and routine inspections can help prevent septic system failure and a septic tank replacement.


Can a concrete septic tank last 100 years?

As a septic system owner you want your septic system life to be as long as possible. A concrete tank can last 100 years, but this would be outside the norm of how long septic tanks last, be it concrete or a steel septic tank.


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