What Is the Difference Between a Septic Tank and a Sewer System?

If you’ve ever wondered whether your home is on a septic system or a city sewer system — or what the difference even is — you’re not alone. They both handle wastewater, but they work in very different ways.

Here’s a simple breakdown of how each one works, how they’re maintained, and why it matters.

Septic systems: private and on-site

A septic system treats your home’s wastewater right on your property. It’s most common in rural areas or places without access to city sewer lines.

Here’s how it works:

• All the wastewater from your home flows into a septic tank buried underground.
• Solids settle at the bottom, and the liquid flows into a drainfield.
• The soil in the drainfield filters and treats the water naturally.

You are responsible for maintaining the system, including regular pumping and repairs.

Sewer systems: public and centralized

A sewer system is managed by a city or county. Instead of treating the water on your property, it gets carried through underground pipes to a municipal treatment plant.

Here’s what happens:

• Wastewater leaves your home and flows into the public sewer network.
• It travels to a central treatment facility.
• The facility removes harmful materials and safely releases treated water back into the environment.

The city handles all maintenance and treatment, but you usually pay a monthly sewer fee.

Key differences

Here’s a simple breakdown of how septic systems and sewer systems compare:

Location

• Septic: Everything is located on your property (tank and drainfield).
• Sewer: Wastewater travels through public pipes to a treatment plant.

Maintenance

• Septic: You’re responsible for pumping and repairs.
• Sewer: Maintenance is handled by the city or local utility.

Upfront cost

• Septic: Usually more expensive to install.
• Sewer: Lower cost if you’re already connected.

Ongoing cost

• Septic: No monthly sewer bill, but you’ll pay for pumping every few years.
• Sewer: Monthly sewer fees are added to your utility bill.

Where they’re common

• Septic: Found in rural and some suburban areas.
• Sewer: Found in cities and densely populated neighborhoods.

Which one is better?

There’s no right or wrong system — it depends on where you live. Septic systems give you more control, and often lower monthly costs. Sewer systems are more hands-off but come with regular utility bills.

If you're building or buying a home, it’s good to know which system you're using so you can plan for the care it needs.

Bottom line

Both systems get the job done — they just do it differently. Septic systems handle waste privately on your property, while sewer systems send it off to be treated by the city. Knowing the difference helps you take care of your home and avoid problems down the road.