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Septic Tank Smell – Causes & How to Avoid It




November 23, 2023



Septic Tank Smell

Table of Contents

A septic tank is an underwater sedimentation tank made of concrete, glass, or plastic, used for treating wastewater through biological decomposition and drainage, thus involving natural processes and proven technologies side by side. It helps treat wastewater from household plumbing systems, including bathrooms, kitchens, and laundry.

Although septic tanks smell foul, they are designed to constrain the smells, and if you are feeling an unpleasant smell outside the tank or from the kitchen and bathrooms, there can be a problem that requires treatment.

Causes of Septic Tank Odours

Septic tank smell can be the result of different causes, including:

  • Improper waste digestion, due to which waste is not being processed effectively, and its build-up can result in an awful smell.
  • Oxygen shortage can lead to poor aeration, due to which aerobic bacteria become anaerobic and cannot digest the organic waste, which leads to more solid waste and sludge in the tank.
  • Excess contaminants which should not be present in the septic tanks, such as chemicals, fats, detergents, greases, oils, etc., can become clogged up, leading to bacterial destruction or reduced digestion.
  • Poor ventilation can result in inefficient emission of gases from the tank, leading to smells inside it.
  • When the tank becomes full and requires desludging.
  • A crack in the soil stack can cause seepage of odours in your home. Complete or partially blocked drains and soakaways can also cause the septic tank smell.
  • The presence of food waste in the septic tank can result in developing odours and blockages.
  • A loose or cracked cleanout access plug can cause the leakage of sewer gas.
  • A hole or leakage in the drain line, plumbing joint, or under the sink.
  • Cold weather can lead to ice build-up around the vent, due to which gases become trapped inside.
Septic Tank Smell – Causes & How to Avoid

Causes of Septic Smells in Bathrooms & Toilets

  • Flushing anything instead of 3P’s (Pee, Poo, and Paper) in the septic tank system can put it under strain by weakening or destroying the good bacteria and increasing the sludge.
  • Failure of the septic tank system can cause foul smells.
  • Less usage of a specific toilet can cause the U-bend to dry up because of water evaporation, leading to the smell.

Signs and Symptoms of Problems

You might notice some unusual signs that indicate potential issues with the septic tank system, such as a gargling sound coming from the sink, slower functioning of the washing machine, sluggish toilet, etc.

Septic Tank Smell – Causes & How to Avoid It

How to Avoid Septic Tank Smell?

  • Septic tanks can be maintained easily to keep them odourless by the following easy steps:
  • You should focus on your habits and not flush anything besides 3P’s into your flush system.
  • You can increase the number of bacteria in a septic tank by microbial septic tank treatment.
  • You should regularly monitor the tank level to identify the potential problem beforehand.
  • You should use biodegradable and recyclable tissue paper in the toilets and bathrooms.
  • You should clean the plumbing vent regularly to avoid debris, leaves or birds’ nest build-up.
  • You should install a new wax ring in the toilet if it becomes dried up.
  • You should check if the risers and utility holes are adequately covered.
  • You should inspect the septic system pipes so that any broken or cracked spots can be repaired.
  • You should not flush in-organic water in the toilet, such as sanitary products, trash, cigarette butts, etc.
  • You should add a cup of baking soda to the sink drain or toilet at least once a week to maintain the pH level in the tank.
  • You should extend the vent stack length if it is at the ground level to avoid septic odours.
  • You should check for ice around the vent in cold weather, or you can insulate the pipes to keep them warm even during cold days.
  • You should clean the septic tank at least once a year to efficiently remove sludge.
  • You should regularly fill the drain traps with water so they do not get dry.
  • You can use an oxy-tonic-biomass accelerator to add oxygen to enhance aerobic activity and waste digestion.
  • You should use carbon filters inside the plumbing vent to reduce septic smells.
  • You should consult with a professional plumber in case of any significant issues.

Regular monitoring and maintenance of the septic tank will reduce the heavier costs associated with pump-outs and enhance its longevity.