What is a Septic Tank and What Does it Do? Explore 5 Most Popular Types
Let’s kick this off with the most basic question, what is a septic tank? A septic tank is a watertight container that collects wastewater from homes and businesses not connected to a municipal sewer system. The most common types are the underground septic systems. It separates solid waste from the liquid effluent and allows the liquids to seep into the soil while the solids remain in the tank. Fats and oil normally float at the top forming a scum layer. The septic tank also allows for biodegradation of organic matter through the use of bacteria.
So how does a septic tank work? Septics are a vital component of on-site sewage facilities (OSSFs), acting as primary waste treatment systems. The tank is usually buried in the yard near the house and has a leach field that helps disperse the wastewater. As the effluent percolates the soil, it undergoes further filtration and microbial action further treating the released waste. That said, it’s vital to have the septic tank properly engineered and safely installed to allow the accumulation of sludge without allowing untreated sewage to leak into surrounding areas thereby contaminating groundwater.
Septic systems are often the only wastewater treatment option in rural areas. There are several different types of septic tanks, each having its own set of advantages and disadvantages. This article will look at five types of septic tank systems that you should know about:
Types of Septic Tanks: 5 Conventional Options
Septic tanks are designed according to rigorous standards, including those set by the Environmental Protection Agency (EPA) in the U.S. and ASTM C1227 for precast concrete septic tanks. These standards ensure that septic systems not only treat wastewater effectively but also protect groundwater from contamination. Most septic tanks, whether concrete, plastic, or fiberglass, must adhere to local zoning and health codes which dictate their sizing, placement, and maintenance schedules.
Here are the different types of septic tank waste management systems to consider for your property.
Concrete Septic Systems
Concrete septic tanks are the most popular option. They're generally made of precast concrete and reinforced with steel rebar.
PROS
Concrete septic tanks are more durable than steel or high-density polyethylene septic tanks, and they can withstand large loads with little risk of damage during backfill. They become increasingly sturdy with time and can tolerate heavy loads and soil pressure while remaining resilient to damage. The tank’s natural curing process ensures the tank becomes stronger and watertight.
CONS
If the concrete fractures, waste may seep out and allow groundwater or rainwater to seep into the reservoir. Ground movement or improper septic tank installation may account for these cracks. To avoid overwhelming the system in such mishaps, ensure proper septic system installation and periodic tank inspection.
Plastic Septic Tanks
Plastic septic tanks are made from high-density polyethylene (HDPE) and are often used in areas where soil conditions are not suitable for concrete septic tanks. They are available starting from 200 gallons to as huge as 10,000 gallon capacities.
However, the 1000 gallon septic tank is the most common among the plastic category.
PROS
Plastic tanks are long-lasting, lightweight, and reasonable in price. Plastic septic tanks don't rust and have a lower risk of cracking than concrete ones. Plastic septic tanks are also more corrosion resistant, hence might have a long lifespan with proper maintenance and regular septic tank cleaning.
CONS
Due to their lightweight construction, plastic tanks are susceptible to shifting or "floating" if not properly anchored, especially in areas with high water tables. Care must be taken during septic tank installation to ensure no damage to the plastic.
Regular septic tank pumping is crucial to ensure longevity of your onsite wastewater management unit. Before installation, a professional should conduct a percolation test to evaluate soil drainage. Additionally, installers must assess the frost line depth, as frost can shift improperly buried plastic tanks, causing system failures. This makes site-specific design and professional installation crucial for the long-term performance of plastic systems.
Fiberglass Septic Design
Fiberglass septic tanks are made from fiberglass-reinforced plastic (FRP). They are often used in areas where space is limited or where soil conditions are not suitable for concrete or plastic septic tanks.
Fiberglass septic solutions are manufactured by layering resin-impregnated glass fibers. This provides a strong, lightweight, and corrosion-resistant structure that’s easy to transport and install. These tanks can be buried in almost any soil type without fear of cracking.
PROS
Fiberglass septic tanks are lightweight and easy to install in hard-to-reach areas. They are extremely resistant to environmental damage or corrosion making them ideal where soil conditions may degrade other materials.
CONS
They are more likely to shift when the surrounding soil becomes saturated or waterlogged. Fitting a fiberglass septic tank requires keenness and attention to detail to ensure proper anchoring.
Portable Septic Units
Portable septic tanks are temporary septic tank systems that can be used when a permanent system is not feasible, and are frequently used for mobile homes, RVs, and job site trailers. They are typically made from plastic or fiberglass and can be easily moved from one location to another.
They are available with wheels for towing, as well as above-ground septic tanks and below-ground storage units. They have a low-profile design that allows these tanks to slide under trailers, leaving an exposed corner for pumping. These tanks may be connected in a series to increase volume to the needed amount.
PROS
Allows sewage to be stored safely in a temporary environment and is ideal for remote or temporary situations.
CONS
Typically holds 18-25 gallons and must be emptied frequently. Treatment capabilities are also limited, unlike permanent systems.
Aerobic Septic Systems (Aerobic Treatment Units – ATUs)
Aerobic sewage systems aerobically inject oxygen into waste to encourage the growth of aerobic microbes that decompose and filter the liquid and solids. Simply put, ATUs mimic a miniature sewage treatment plant. Aerobic septic systems significantly reduce the risk of groundwater contamination in areas with shallow aquifers or fragile ecosystems. In some cases, treated effluent can be reused for landscape irrigation, reducing overall water consumption—a key factor in areas prone to drought or water shortages.
PROS
Aerobic systems are often paired with a smaller leaching field than a comparable conventional septic system. This can save a lot of room, which is particularly advantageous in areas where a large drainage area is prohibited.
CONS
These systems employ electric pumps to move air through wastewater, so the site must have electricity and the homeowner must pay for ongoing usage. These are considerably more complicated systems than traditional gravity-powered septic tanks, hence their higher recurring upkeep expenses.
Septic Tanks from Tank Depot are a Homeowner's Best Option
If you are in the market for a septic tank, Tank Depot is the best place to go, and we will beat anyone's price for the same tank. We offer various sizes and configurations, including portable septic tanks, which are perfect for temporary applications.
We have been providing septic tanks to homeowners and businesses for over 25 years, and we are committed to performing the best service possible. Contact us today to learn more about our septic tanks and find the perfect one for your needs.