Wastewater leaves your home in one of two ways- septic or sewer.  

These two systems do the same job in different ways. Both systems treat wastewater and release it back into the environment. Septic systems are individually owned and responsibility falls on the owner, while towns and cities hold responsibility for sewer line maintenance.

One common question that comes up is, septic tank vs sewer: which is better for the environment?

It’s an important topic and one that requires an in-depth look into each system. Read on to discover the answer.

Septic Tank VS Sewer

Before comparing the effects on the environment, it’s important to understand the difference between the two systems and how each one works. 

How Do They Work?  

A septic system consists of a septic tank and a drain field. 

A septic tank is an underground structure that naturally treats wastewater from your household plumbing such as the kitchen, bathroom, and laundry room. A sewage line carries the waste into the tank where materials separate into three layers: sludge, water, and scum. Water is pushed into the drain field where it’s slowly released back into the soil.

Septic systems need maintenance. Depending on tank size and the number of people living in the household, solid material needs to be pumped from the tank every three to five years.

A sewer system is an underground network of pipes that carry wastewater away from houses, commercial buildings, and storm drains to treatment facilities. 

Wastewater goes through many phases of treatment before it’s released into receiving waters. 

Septic Systems  

The septic system has been used for 160 years and over 21 million households in the U.S. use this system today for wastewater removal. Septic systems require regular maintenance and tank failure is disastrous for the homeowner and the environment. 

Four Common Reasons Why Septic Tanks Fail

1. Lack of Maintenance

Septic pumping needs to be done regularly or sludge and scum will continue to buildup inside the tank until it’s eventually pushed out into the drain field, soil, or back into your home.

Bacteria also needs to be added to the tank periodically to ensure that waste is properly breaking down. 

2. Excessive Water Use

Septic tanks can only process a certain amount of waste at a time. Your system should process waste at the same rate it takes water. If it’s taking on too much water, waste will go back into your home or onto your lawn.    

3. Damage 

Septic systems have four main components. If any of these are damaged, the entire system could be compromised. Tree roots, clogs, and paving on the drain field are some of the biggest causes of damage. 

4. Improper Installation

These systems must be buried at a certain depth and in a specific type of soil. If it’s installed in the incorrect type of soil, wastewater won’t be absorbed and dispersed safely.  

Sewage can contaminate groundwater and surrounding soil if your septic system isn’t properly installed.  

Environmental Impact

Septic system maintenance and proper installation are of the utmost importance, not only for your home and wallet, but for the environment as well. A failing system leaks raw sewage and other contaminants such as phosphates, nitrates, disease-causing microorganisms, heavy metals, and chemicals into the surrounding soil, groundwater, and eventually your drinking water.

The bacteria and viruses that cause dysentery, hepatitis, and typhoid fever can end up on the surface and in groundwater causing environmental issues and public health problems.

Phosphorus and nitrogen cause massive plant and algae growth in freshwater environments. When these plants and algae die and decompose, they use up the oxygen in the water, causing hypoxia. Hypoxic waters are unable to support life. 

Make sure your tank is regularly pumped, watch what you put down the drain, and conserve as much water as possible.  

Sewer Systems  

Since the Clean Water Act was enacted in 1972, the U.S. has regulated the pollutants that enter the water and has established a standard of quality for surface waters. Wastewater management in the United States is largely taken for granted. These systems require maintenance through large investments to make sure they function properly. 

The acting deputy assistant administrator for water at the EPA stated that $271 billion is necessary to maintain wastewater infrastructure in the U.S. under the Clean Watersheds Needs Survey.     

Wastewater treatment is an attempt to purify and treat the water as much as possible before it’s released back into the environment. 

Environmental Impact

Sewer systems are not 100% efficient. Contaminants still get through treatment and are released back into the environment.

One of the biggest causes of aquatic pollution is plastic microfibers. These are thread-like fibers that come from natural and synthetic materials.

The majority of these fibers come from conventional clothes washing and have been found in oceans, rivers, soil, animal life, and consumer products. It’s been estimated that 35% of microplastics in the oceans come from synthetic clothing. 

Why are microplastics bad for the environment?

Microplastics are not removed through wastewater treatment. 

While there is a degree of uncertainty, microplastics absorb and release toxic chemicals and pollutants. These pollutants can build up over time in our bodies and the environment. It is unknown whether these toxicities can be ingested through contaminated seafood. 

Which Is Better?

When it comes to septic tank vs sewer, each system has its pros and cons.

Septic systems need to be properly maintained to prevent contamination of the soil and groundwater. Microplastics and small amounts of other pollutants get through wastewater treatment and have been found in the environment all over the world.

Wastewater management technology is still advancing with the goal of achieving 100% efficiency.   

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