If your home is built in close proximity to a municipal sewer hookup, you can utilize a sewer line as a means of doing away with waste. If your home doesn’t have access to such a hookup, you’ll instead need to use a septic tank. 

What’s a septic tank? How does a septic tank work? We’re going to answer these questions and more below. 

What Is a Septic Tank?

A septic tank is a storage container that holds and breaks down waste. It’s connected to a home’s drains and receives everything from toilet water to dishwasher water to washer water and more. It, of course, also receives the solid matter that exists within this water. 

Septic tanks possess two pipes, one of which connects to their respective homes, and the other of which empties into their adjacent drain fields. A drain field is essentially just an area of soil filled with strategically-placed bacteria. Its purpose is to filter out matter within the wastewater. 

Septic tanks come in a range of sizes but usually span between 750 gallons and 1,250 gallons. They’re buried underground and are entirely invisible to those using them. 

If you live in a rural area, you might very well have to use a septic tank. This is because rural areas are often without municipal sewer hookups. As such, septic tanks are their only legitimate option for sewage disposal. 

How Does a Septic Tank Work?

A septic tank works by accepting wastewater from the inside of the home. It then holds this wastewater until it’s able to separate into different layers. These layers include the scum layer, the water layer, and the sludge layer. 

The scum layer is at the top of the septic tank. It consists of greases and oils that slowly separate from the water. 

The sludge layer is at the bottom of the septic tank. It consists of solid materials that were put into toilets and drains. 

The wastewater sits between these two layers, slowly allowing sludge and scum to leave it over time. Once it’s free of sludge and scum, this water flows out of the septic tank, ending up in a designated drain field. 

Now, how does the septic tank cause the wastewater to separate into layers? It makes use of anaerobic bacteria. These eat away at the wastewater, causing it to break down into its individual components. 

Anaerobic bacteria exist outside of the septic tank as well, sitting within the drain field. This way, they’re able to further break down wastewater before it settles into the ground and mixes with existing groundwater. 

Understanding the Need to Empty a Septic Tank

Now, you might think that because the water eventually leaves a septic tank, the septic tank never really needs to be emptied or cleaned. However, in fact, septic tank emptying is vital. 

See, while the water may leave the septic tank, the scum and the sludge do not. And over time, these substances can accumulate to the point that they clog the tank. 

What happens when scum and sludge clog the tank? It isn’t able to accept sewage and therefore causes it to back up into the house. 

Therefore, it’s imperative that you empty your septic tank from time to time, usually once every 3 to 5 years. You’ll also want to clean the filter in your septic tank on a yearly basis. 

If you need assistance with any of these tasks (and you probably do, particularly when it comes to emptying the tank), you can call your local plumber or septic company. They’ll pump out all of the existing scum and sludge, ensuring that your tank is clean and ready to accept additional sewage. 

For more information on septic tank upkeep, read this article on septic cleaning and maintenance tips

How Long Does a Septic Tank Last?

Now, you might be wondering: how long does a septic tank last before it goes bad? Generally speaking, septic tanks last 20 to 30 years. Note, though, that the more diligent you are in maintaining yours, the longer it will thrive. 

So, when should you make a change? To determine this, it’s best to look out for specific signs. These signs include the following: 

Is Your Sewage Backing Up Frequently?

If you’re dealing with regular sewage backups, it’s a good indication that you need to replace your septic tank. This, of course, is only true if you’re faithfully maintaining your septic tank. If not, it might just be time for a pump. 

Is the Grass Above Your Drain Field Particularly Green?

In some cases, when a septic tank stops working, it allows raw sewage to flow through it into the drain field. As a result, the sewage acts as a fertilizer, thereby producing exceedingly green and bountiful grass above the drain field. If you notice this in your yard, it’s probably time for a septic tank replacement.  

Do Your Drain Pipes Gurgle?

Another sign that you need a septic tank replacement is that your drain pipes gurgle. Gurgling sounds occur due to clogs and blockages. If clogs and blockages exist, there’s a decent chance that your septic tank is to blame. 

Have the issue assessed by a licensed plumber. They’ll determine the source of the issue and take all necessary action. 

Looking for More Advice About Septic Tanks?

Now that you have an answer to “how does a septic tank work?”, you might be searching for other info on septic tanks. If so, you’re in the right place. Our website has you covered. 

Browse through our selection of articles now! 

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