Aerobic vs Conventional Septic Systems: What’s the Difference?

If your home isn’t connected to city sewer, you likely rely on a septic system to treat wastewater. In Texas and many other states, homeowners typically have one of two types of septic systems: a conventional septic system or an aerobic septic system.

While both systems serve the same purpose, they work very differently. Understanding the differences can help you maintain your system properly, avoid costly repairs, and make informed decisions when buying or building a home.

What Is a Conventional Septic System?

A conventional septic system treats wastewater using anaerobic bacteria, which do not require oxygen. This type of system has been used for decades and is still common in rural areas with suitable soil conditions.

How a Conventional Septic System Works

1. Wastewater flows into a septic tank

2. Solids settle at the bottom as sludge

3. Oils and grease float to the top as scum

4. Liquid wastewater flows into a drain field

5. Soil naturally filters and treats the effluent

Pros of Conventional Septic Systems

• Simple design

• No electrical components

• Lower upfront installation cost

• Fewer mechanical parts to maintain

Cons of Conventional Septic Systems

• Requires large drain fields

• Less effective treatment

• Not suitable for poor soil or high water tables

• Higher risk of groundwater contamination if overloaded

What Is an Aerobic Septic System?

An aerobic septic system treats wastewater using oxygen and aerobic bacteria, which break down waste faster and more thoroughly. These systems are commonly required in Texas due to soil and environmental regulations.

How an Aerobic Septic System Works

1. Wastewater enters a pretreatment (trash) tank

2. Liquid flows into an aerobic treatment chamber

3. An air pump introduces oxygen

4. Aerobic bacteria digest organic waste

5. Water passes through a clarifier and pump tank

6. Treated effluent is dispersed via spray or drip irrigation

Pros of Aerobic Septic Systems

• Produces cleaner effluent

• Works well in poor soil conditions

• Requires smaller dispersal areas

• Meets stricter environmental regulations

• Commonly approved by Texas counties

Cons of Aerobic Septic Systems

• Requires electricity

• More components to maintain

• Higher upfront cost

• Needs regular inspections and service contracts

Which Septic System Is Better?

There is no one-size-fits-all answer. The “better” system depends on:

• Soil conditions

• Lot size

• Groundwater levels

• County requirements

• Homeowner maintenance commitment

In Texas, aerobic septic systems are often required, especially for new construction or properties with challenging soil conditions.

Maintenance Differences Homeowners Should Know

Conventional System Maintenance

• Pump tank every 3–5 years

• Avoid overloading with water

• Protect the drain field

Aerobic System Maintenance

• Regular inspections (often 3 per year in Texas)

• Maintain air pump and control panel

• Monitor spray heads or drip fields

• Pump tanks as recommended

Ignoring maintenance on either system can lead to backups, odors, and expensive repairs—but aerobic systems tend to fail faster when neglected due to their mechanical components.

Final Thoughts

Both conventional and aerobic septic systems are effective when properly designed and maintained. However, aerobic septic systems provide higher treatment quality, making them the preferred—and often required—choice in Texas.

If you’re unsure which system your home has or what maintenance is required, a licensed septic professional can inspect your system and explain your options.