The impact of septic system pollution on water

Category: Others
20 Jan 2023

Aquatic ecosystems provide support for lots of microbial, plant and animal life. They also help in the regulation of water quality through various biological and chemical processes. Suffice it to say that our survival depends on aquatic ecosystems – and this is why we must make deliberate efforts to curb water pollution. Septic systems are some of the potential sources of water pollution. Thankfully, the regulatory framework in Canada and most other nations has helped to ensure responsible management of onsite wastewater treatment to prevent septic system pollution.

How septic system pollution affects us

Septic systems can affect the quality of surface water bodies as well as local drinking water wells. The extent of the septic system pollution depends on how well maintained the septic system is as well as how it is used. If a septic system that is located near a water well is not functioning properly, contaminates from the effluent can find their way into the drinking water and this can result in the breakout of serious diseases. The bacteria, viruses, and protozoa from the wastewater can cause diseases like typhoid, gastrointestinal illness, hepatitis A and cholera. When not properly treated, wastewater has lots of nitrogen from the urine, food waste, feces as well as cleaning compounds. When consumed, these nitrates can result in methemoglobinemia (blue baby syndrome) in infants. This condition reduces the ability of blood in infants to carry oxygen. If this condition is not treated in good time, it can result in the death of the affected infant.

How septic system pollution affects the environment

Lots of household products like fertilizers, soaps, and detergents contain phosphorus and nitrogen which can result in nutrient pollution if the septic system fails. When there are too many nutrients (phosphorus and nitrogen) in surface water, the nutrients act as fertilizers which lead to a heightened growth of bacteria and algae in the water. This rapid growth of algae can reduce the quality of water, kill some aquatic life and introduce some toxins in the water. Algal blooms in lakes and streams have been found to be toxic to both humans and animals. Furthermore, the nutrients have an individual impact on the quality of water.

Phosphorus: unabsorbed phosphorus travels into groundwater and ends up in other water bodies like lakes and rivers. Freshwater bodies are very vulnerable to phosphorus pollution.

Nitrogen: nitrogen that finds its way into the water table will eventually flow into surface water bodies and this can cause health problems to humans. For instance, infants are very susceptible to water that has too many nitrates and this leads to a medical condition referred to as “blue baby”

Bacteria: Contaminants like Escheri Coli and Salmonella can cause various communicable diseases.

Avoiding septic system pollution

Septic systems contaminate groundwater for a variety of reasons. Let us look at some of the most common causes of contamination of groundwater by septic systems and their respective mitigation options.


Most jurisdictions have adopted legislation that provides guidelines on the minimum distance that must be maintained between a septic tank and drinking water wells. Keeping this distance is crucial because it helps to ensure wastewater doesn’t get to the drinking water before it is adequately treated through a combination of biological and physical processes. The complete treatment of wastewater needs a good layer of unsaturated soil thickness. For this reason, you should avoid areas of the property that might have high water tables or ones that have shallow impermeable layers when choosing the location of the septic tank.

It is also important to do a percolation test on the site just to ensure the soil is permeable. If the permeability is wanting, the drainfield might not handle the flow of wastewater efficiently and that might result in ponding. If the percolation rate of the soil is too high, the effluent might reach groundwater before it has been properly treated. On the flip side, if the percolation rate is too slow, the drainfield might get waterlogged which might lead to backups. This is the reason why advanced systems are recommended for karst and other areas that might not be conducive to conventional systems.

Poor design and construction

The design can also determine whether or not the system will cause pollution. Soil topography and related characteristics should be taken into account when designing the septic system. For instance, soils that have a low percolation rate need a larger leach field to give enough time for the treatment of the wastewater. Additionally, the leachfield should be on a flat area to allow for the uniform flow of wastewater in the trenches. When designing septic systems for restaurants, it is imperative to install grease interceptors. That’s because the grease that is produced from restaurants is quite a lot and it could easily cause the septic system to fail. It is also advisable not to construct the septic tank when the soil is wet because there might be too much soil smearing and compaction. You may want to consult a licensed contractor when installing a septic system. The pros will ensure they install the septic system without violating any of the statutory requirements and they will also ensure they do it right to avoid system failure.


Apart from design and construction, proper maintenance is perhaps the most important step in ensuring the septic system doesn’t pollute the groundwater. Neglecting the septic system can result in its failure even if it was properly constructed as per the regulations. It is the responsibility of every septic system owner to monitor their system to make sure everything is working as it should. For instance, they should monitor the drainfield area for any sign of failure which includes surfacing sewage, odors or lush vegetation. Such signs should be taken seriously and attended to before the system fails completely and pollutes groundwater.

Pumping the tank every few years helps to ensure that sludge doesn’t accumulate to excessive amounts. When there is too much sludge in the tank, wastewater will be forced out of the tank prematurely and that can result in clogging of the drain field. It is also important to avoid using products that might harm the bacteria in the septic tank. Most commercial cleaning products are made from compounds and chemicals which are toxic to bacteria. For more details on the products to avoid using to guarantee a healthy septic system, refer to our free ebook.

Here are some more maintenance steps you can take to ensure a healthy septic system:

Don’t overload the system

Hydraulic overload is one of the commonest causes of septic system failure. Bacteria need sufficient time to digest the organic waste but when too much wastewater is sent into the tank at a go, the wastewater leaves the tank too early. It is, therefore, a good idea to avoid overloading the system hydraulically. If there are a number of people in the house, avoid taking many baths in succession. Additionally, spread out your laundry instead of doing a huge load at once. Finally, fix any leaking faucet as soon as you notice it. Even a tiny trickle can have a serious cumulative effect over time.

Protect the system from external damage

It is also important to protect your septic tank from external damage. If the septic tank cracks, effluent will ooze out and find its way into groundwater. Exerting undue pressure on the septic tank can result in damage. You should, therefore, avoid activities like construction or driving heavy machinery above the septic tank. Another possible cause of damage to the septic tank is the roots of plants. These roots are very invasive and they can easily cause cracks in concrete tanks. For this reason, you should desist from planting trees and shrubs near the septic tank. Finally, when doing the routine pumping of the tank, do an inspection of the tank just to make sure there are no cracks.

Use biological additives

Biological additives are made from enzymes and bacteria and they can help to improve the efficiency of your septic tank. These additives introduce billions of bacteria and enzymes into the septic tank which will help in the liquefying of organic waste.  By so doing, the bacteria will prevent septic system pollution and it will ultimately increase the longevity of your septic system. We recommend using bio-sol’s biological additives every month. Bio-Sol has been providing biological additives services since 1992 and these additives have helped to save lots of septic tanks from imminent collapse.

Avoid harmful products

An average septic system has approximately 100 distinct traceable chemical pollutants. These pollutants originate from household products that are used in the sinks, shower, and toilet. Most of the chemical products used for cleaning are actually quite toxic to bacteria. For instance, antibacterial soaps are designed to kill bacteria so it does exactly that when it reaches the septic tank. Any septic system owner should, therefore, avoid using such products because they kill bacteria in the septic tank which affects the efficiency of the septic system.



There is no denying that septic systems play a vital role in the treatment of wastewater in homes that are not connected to the municipal sewer system. As urban sprawl continues to grow every decade, the need for septic systems will continue to rise. The solution to septic system pollution on the water is therefore not to stop using the septic systems but rather to be responsible users of the same. This means using the septic system as it was meant to be used and following all the necessary maintenance procedures. That will guarantee healthy and long-lasting systems that will not pollute groundwater.

About the author


CEO at Bio-Sol

Our goal is not only to offer you the best products on the market but also to educate and empower you with the insights you need for successful wastewater treatment.


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