How Long Do Septic Tanks Last?

If you live in a suburban or rural area, there is a good chance you own a septic tank. You may not think very often about this vital underground system, but it is always there working hard to treat your wastewater in a safe, environmentally-friendly way.

How Long Does a Septic System Last

When septic tanks malfunction, however, they can cause more than just a foul stench — they can also create a major inconvenience and lead to costly repairs.

How Long Does a Septic System Last?

The septic system can last up to 26 years — or indefinitely in rare cases. The service life of the septic system completely depends on its maintenance. If you get regular inspections and make repairs as needed, your concrete septic tank can last longer than a lifetime.

The service life of the septic tank also depends on its construction material:

  1. Steel Septic Tank: A steel septic tank will rust out on a schedule affected by soil acidity and tank steel quality and coating integrity. A steel septic tank more than 15 or 20 years old is likely to have already rusted to the point of having lost its baffles and perhaps having a rusted-out bottom – conditions that can be recognized during septic tank cleaning and inspection. A steel septic tank cover lasts until some fool drives over it, or it rusts out.
  2. Concrete Septic Tank: A concrete septic tank can last 40 years to nearly indefinitely, though poor quality concrete or acidic groundwater may result in deteriorated baffles or tank components.
  3. Conventional Septic Tank: A conventional septic drain field has a varying life as a function of the soil percolation rate, drain field size, and usage level.

Factors Affecting the Septic System Life

The life of your septic system depends on the following factors:

  • Septic Tank Pumping Frequency: The most significant step you can take to extend the septic system life is to have the septic tank cleaned or “pumped” on schedule.
  • Design and quality: Proper installation, a well-chosen location, and good soil will all improve the lifespan of your septic tank and septic system as a whole. If your tank is installed poorly, it will likely not last as long as it could otherwise. If you install your tank in a location that experiences frequent flooding, the leach field may get clogged, which will also affect its lifespan. Even a high-water table or inferior soil conditions can decrease the longevity of your system.
  • Soil Conditions, such as the soil percolation rate and the amount and level of groundwater or surface water, affect the soil absorption area or drain field.
  • How the Septic System is Used: Including the wastewater usage level and what materials are flushed down the septic system drains. Conserving water reduces the load on the absorption field. Avoiding flushing chemicals or items that don’t biodegrade reduces the solid build-up rate in the septic tank.
  • Septic Tank Materials: A steel septic tank rusts away, first losing its baffles (which leads to drain field clogging) and eventually rusting at its bottom or sides. The rate of rust depends on the soil conditions, soil acidity, and other factors. A concrete septic tank can have a very long life, in excess of 40 years, except for cases of poorly-mixed concrete or possibly acidic soils, which may reduce that span. Plastic or fiberglass septic tanks can expect to have a similar life unless they are mechanically damaged.
  • Workload: How often the system is used also affects its life expectancy. Using your system less can prolong its lifespan as well as require less maintenance, which leads to significant savings.
  • Life of Special Components: The septic tank components such as effluent pumps or septic grinder pumps, septic filters, septic media, and sand bed filter systems often determines the need for repair of alternate-design septic systems that use these components.
  • Water & wet sites: Sending surface or roof runoff into a drain field area or locating a septic soak-away bed in wet soils, near a high-water table, near creeks or streams prone to flooding all mean short life as well as maybe an improper or illegal installation.
  • What goes in: You can also increase your tank’s lifespan by taking care not to flush down any chemicals or non-biodegradable materials.
  • Water usage in the building: The level of water usage in a building also affects the drain field and unusual or abnormal levels of water usage, such as constantly running toilets.

Read More: Types of Septic Tanks

FAQ Section

Can Septic Tanks be repaired?

They can, although the costs vary widely depending on which part of the system needs to be fixed. The tank lid, for example, is one of the least expensive parts to replace, while the drain/leach field is often one of the most expensive parts to replace. It depends especially on the size of the tank and where it’s located.

What are the signs of a bad septic tank?

  • Water and sewage from toilets, drains, and sinks backing up into the home’s plumbing.
  • Bathtubs, showers, and sinks drain very slowly.
  • Gurgling sounds in the plumbing system.
  • Standing water or damp spots near or over the septic tank or drain field
  • Sewage odors around the septic tank or drain field.
  • Bright green, spongy lush grass over the septic tank or drain field, even during dry weather.
  • Straight pipe discharging untreated wastewater to the ground surface
  • Algae blooms in nearby lakes or water bodies.
  • High levels of nitrates or coliform bacteria in surface waters or drinking water wells.

Can a septic system last 50 years?

Under normal conditions and good care, a leach field will last for 50 years or more. Concrete septic tanks are sturdy and reliable but not indestructible.

How often should a septic tank be changed?

On average, a properly installed and well-maintained septic tank can last 20 to 30 years. Concrete septic tanks, the most common tank type found today, can last quite a long time. Generally speaking, concrete tank owners don’t need to think about septic tank replacement hassles for about 20 to 30 years.

How do I keep my septic tank healthy?

  • Regularly inspect and maintain your septic system
  • Pump your septic tank as needed.
  • Keep your septic tank lids closed and secured
  • Be water-wise
  • Direct water from land and roof drains away from the drain field
  • Keep septic tank lids easily accessible

How can I increase bacteria in my septic tank naturally?

Bacteria will grow naturally in your septic tank. You promote the growth of bacteria by flushing more solid waste down into the tank all the time.

Does a lot of rain affect the septic system?

It is common to have a septic backup after or even during heavy rain. Significant rainfall can quickly flood the ground around the soil absorption area (drain field), leaving it saturated and making it impossible for water to flow out of your septic system.

How long can a septic tank last without being pumped?

As a general rule, you should ideally empty out your septic tank once every three to five years. However, the actual frequency will vary depending on usage and how many people live in your household.

Should you put additives in your septic tank?

Chemical septic tank additives can actually harm the tank by killing the bacteria and polluting the environment. It is, therefore, a good idea to avoid them altogether.

How long does a concrete septic tank last?

The service life of a septic tank depends on different factors, such as tank material, tank maintenance, or water usage in the building. Your steel tank baffles will rust out in 15 to 20 years and may collapse if driven over, but a concrete tank will last 40 years or more as long as the wastewater is not acidic.

How long does a plastic septic tank last?

The average lifespan of a plastic septic tank is 30 years. Plastic tanks are more vulnerable to stress and more challenging to install, which can shorten their lifespan.

How long does a septic drain field last?

Under normal conditions and good care, a drain field will last for 50 years or more. 

Read More
  1. Symptoms of bad Septic Tank
  2. Septic System Cleaning and Pumping Costs
  3. Working of Aerobic Septic System

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