What Is an Anaerobic Septic System and Is It Right for Your Home?
Keep your home waste-free with this popular type of septic system
Highlights
Anaerobic septic systems store and remove waste from your home.
They’re used in rural or suburban houses that don’t have public sewage access.
In an anaerobic system, household waste flows into a septic tank.
Anaerobic bacteria break down solid waste inside the tank.
Wastewater flows back into the soil outside through a system of pipes.
If you live in a rural area or somewhere that doesn’t have a public sewage system, you probably use a septic system to get rid of waste safely, but do you know much about how your septic system works? There are quite a few types of septic systems, with one of the most popular being the conventional anaerobic septic system. Whether you already have an anaerobic system or you’re considering installing one, here’s an overview of how they work, how they compare to other systems, and how to know if they’re right for your home.
What Is an Anaerobic Septic System?
An anaerobic septic system is a waste management system commonly used in rural and suburban homes. One of its central features is a watertight underground or above-ground septic tank, which collects waste from your sinks, showers, and toilets whenever you flush or let water run down the drain.
So, how does an anaerobic septic system work? Inside the tank, solid waste sinks to the bottom, while the liquid wastewater rises. The solid waste is broken down by anaerobic bacteria, which don’t require oxygen to live (which is where the name “anaerobic” comes from).
Wastewater, on the other hand, moves into a set of underground distribution pipes in an area known as the drain field or leach field. The wastewater slowly filters out into the soil through holes in the pipes.
Anaerobic vs. Aerobic Septic Systems
Historically, anaerobic septic systems were the most common types of septic systems in the U.S. But these days, many people are choosing aerobic systems. Here are some of the differences between the two.
Presence of Oxygen and Type of Bacteria
The main differentiator between anaerobic and aerobic septic systems is the presence of oxygen in the respective septic tanks, which impacts the type of bacteria inside.
As we’ve mentioned, anaerobic systems don’t have oxygen inside, so the bacteria that live there must be able to survive without it. But aerobic septic systems have an aerator feature that injects oxygen into the waste, where it’s broken down by aerobic (oxygen-consuming) bacteria.
Size
Anaerobic systems aren’t as efficient as aerobic ones, so they require more piping and larger drain fields. If you don’t have a ton of space in your yard, an aerobic septic system might be a better option.
Cost
There’s also a stark price difference between the two. On average, anaerobic septic systems cost anywhere from $3,000 to $8,000, while aerobic systems are much pricier, costing between $10,000 and $20,000. Something else to keep in mind: The aerator in an aerobic septic system needs power to run, which can increase your operating costs.
Is an Anaerobic Septic System Right for You?
If your home isn’t connected to the public sewer system, then you’ll likely use a septic system—but is an anaerobic system the right choice for your needs?
On the plus side, anaerobic systems are usually more affordable than other types of septic systems, including aerobic, mound, and drip distribution systems. Plus, unlike some other systems, they don’t need electrical power to run, which makes them more efficient and better for your wallet.
However, there are some potential drawbacks, as well. Notably, anaerobic systems take up more space than some other kinds of septic systems. That’s because their distribution pipes are designed to evenly distribute wastewater throughout the soil. So, if your property is fairly small, an anaerobic septic system might not be the best choice for you.
If you’re considering an anaerobic system, also keep in mind that your soil has to allow for quick percolation, or the process of treated wastewater absorbing into the soil. You need to hire a pro to do a perc test on your yard to check its percolation rate. Not every yard is suitable for an anaerobic septic system.
Anaerobic Septic System Maintenance Tips
Septic systems play a critical role in your home by safely disposing of water and waste. To keep your system running smoothly (and avoid potentially pricey septic tank repairs), it’s important to take proper care of it. Here are a few tips to keep in mind.
Know what you can (and can’t) put into your septic system: Dealing with clogged toilets and backed-up drains is never fun. To prevent these types of problems, don’t put things like chemicals, paper towels, baby wipes, or personal hygiene products into your system. Basically, the only things that should go down your toilet are septic-safe toilet paper and human waste.
Pump your septic tank: Every three to five years, you should hire a plumber or septic tank pro to pump your septic tank. Regular pumping can help prevent waste from building up inside your tank, leaking out into your drain field, and backing up your pipes. Typically, a one-time septic tank pump costs around $400.
Look after your drain field: Keep your drain field free of any obstructions in case problems arise and a pro needs to access it. Also, keep all roof drains and downspouts pointed away from the field; otherwise, the field could soak up too much water and overflow.
Know when to call a pro: It’s best to have a professional septic inspection every few years. But you should also call a local septic tank company any time something seems off. Common signs of a septic system problem include backed-up plumbing, slow drainage, foul odors, and standing water in your drain field.
Frequently Asked Questions
Neither system is necessarily better or worse than the other, but one of the two might be better for your needs. For example, anaerobic systems are less expensive than aerobic ones and don’t use power to run. On the other hand, aerobic septic systems don’t take up as much space and are typically more efficient than their anaerobic counterparts.
On average, septic systems last between 15 and 20 years. However, with proper care and routine septic maintenance, you may be able to extend your septic system’s life span to 30 years (or more). Some ways to keep your system in tip-top shape include scheduling a professional inspection every two to five years and reducing the flow of wastewater into your system.
Several things can ruin a septic tank over time, including dumping harsh chemicals (like bleach and ammonia), pesticides, and paint thinners down your drain because they can kill the bacteria in your septic tank. You should also make sure to only flush waste and toilet paper in your toilet—otherwise, you could clog your system.
Many septic professionals agree that spring is the best time of year to empty a septic tank. By this point, the temperatures have usually warmed up enough so that the ground is no longer frozen, which makes it easier to access the tank (and less likely for the waste to be frozen inside the tank). Summer and fall are also decent times to do it, but winter isn’t.