Septic Tank & HSTP Maintenance: How Often Should Your Wastewater System Be Serviced?

Your wastewater system probably isn't something you think about very often—and when it's working properly, you shouldn't have to.

But whether your property relies on a traditional septic tank, Home Sewage Treatment Plant (HSTP), Aerated Wastewater Treatment System (AWTS) or another onsite wastewater system, regular maintenance plays an important role in keeping it working reliably.

The tricky part is knowing how often your wastewater system actually needs to be serviced.

Does a septic tank need servicing every three months? How often should it be pumped out? What about a home sewerage treatment plant? And what happens if you miss a scheduled service?

The answer depends heavily on the type of system installed.

At Hughes Plumbing Contractors, we work with septic and wastewater systems across South East Queensland. Here's what homeowners need to know about looking after their system—and why septic tanks and HSTPs shouldn't be treated as though they're the same thing.

Septic Tank or HSTP? Know What You Have First

Before worrying about a maintenance schedule, it helps to understand what is actually installed at your property.

A traditional septic system is relatively simple. Wastewater enters the septic tank, where solids settle and wastewater undergoes treatment before effluent moves to the property's approved disposal system.

A Home Sewage Treatment Plant (HSTP) provides additional treatment using mechanical and biological processes. Depending on the system, this can involve components such as pumps, aeration equipment, filters and disinfection before treated wastewater is distributed through an approved land application area.

You may also hear terms including:

• Home Sewage Treatment Plant (HSTP)

• Household Sewage Treatment Plant

• Aerated Wastewater Treatment System (AWTS)

• Onsite wastewater treatment system

• Domestic wastewater treatment plant

While terminology varies, the important point for homeowners is that a treatment plant generally requires more regular professional servicing than a traditional septic tank.

How Often Should a Home Sewage Treatment Plant Be Serviced?

For many Queensland homeowners with an HSTP or AWTS, scheduled servicing is typically required at regular intervals—commonly every three months for many systems.

However, you shouldn't assume that every wastewater treatment plant follows exactly the same schedule.

The correct servicing frequency depends on factors including the particular treatment system, its approval and manufacturer requirements, and applicable local requirements.

If you've recently purchased a property and aren't sure when the system was last serviced, it's worth finding out rather than waiting for an alarm or wastewater problem to appear.

Your service records, previous service provider or information associated with the installed system may help establish the correct maintenance schedule.

What Happens During an HSTP Service?

A proper wastewater service is more than somebody lifting the lid and checking that the tank is still there.

The exact service procedure depends on the system, but a wastewater technician may need to inspect the operation and condition of various components and confirm that the treatment process is functioning as intended.

Depending on the particular HSTP, servicing may include checking:

Mechanical components Pumps, blowers or aeration equipment may be inspected to make sure they're operating correctly.

Treatment performance The system can be assessed to determine whether wastewater is being treated as intended.

Sludge levels Accumulated solids may need monitoring so they can be managed before they begin affecting system performance.

Filters and other components Components requiring cleaning, adjustment or maintenance can be addressed as appropriate for the particular system.

Alarms and controls An alarm isn't very useful if it fails when the system develops a problem.

Disinfection system Where applicable, the system's disinfection process may require checking and maintenance.

Land application area Obvious problems with irrigation or effluent distribution may also need attention.

The purpose is simple: find developing problems while they're still maintenance issues rather than waiting until they become wastewater emergencies.

What About Traditional Septic Tanks?

Traditional septic tanks are different.

They don't generally need the same quarterly mechanical servicing as many HSTPs because they don't contain the same treatment equipment.

That doesn't mean a septic tank is maintenance-free.

Solids gradually accumulate inside the tank and, eventually, they need to be removed.

The system's condition, household usage and disposal area also need attention over its lifetime.

One of the most important aspects of septic tank maintenance is having the tank pumped out when required.

How Often Should a Septic Tank Be Pumped Out?

There's no single pump-out interval that's correct for every household.

How quickly solids accumulate can depend on:

• Tank size

• Number of people living in the home

• Household water use

• What is being flushed or washed down drains

• System condition

• Previous maintenance

• How the septic system is being used

Rather than relying on a calendar alone, the condition and sludge accumulation within the system should help determine when pumping is necessary.

Waiting until sewage starts backing up is not a good maintenance strategy.

Likewise, automatically pumping a tank unnecessarily isn't the goal either.

A wastewater professional can help you understand an appropriate maintenance approach for your particular septic system.

Why Does Regular Wastewater Maintenance Matter?

A septic or wastewater treatment system deals with virtually everything leaving your home's toilets, showers, sinks and other connected fixtures every day.

When something goes wrong, the consequences can be unpleasant.

Poorly maintained or malfunctioning systems may contribute to problems such as:

• Unpleasant sewage odours

• Slow drains

• Gurgling plumbing

• Wastewater backing up into the house

• Alarms activating

• Pumps or blowers failing

• Wastewater surfacing around the property

• Irrigation or disposal problems

• Reduced treatment performance

• More expensive repairs

Regular maintenance doesn't guarantee that a component will never fail.

What it does provide is an opportunity to identify deterioration and developing faults before you're standing in the backyard wondering why it smells like sewage.

What Are the Signs Your HSTP Needs Attention?

You don't need to wait for the next scheduled service if something isn't right.

Contact a wastewater professional if you notice:

• An alarm light or buzzer

• Persistent unpleasant odours

• Wastewater pooling around the system

• Unusual noises from pumps or blowers

• Irrigation that isn't operating normally

• Soggy or unusually wet areas around the disposal area

• Toilets or drains becoming slow

• Gurgling from household drains

• Sewage backing up

• A noticeable change in how the system operates

An alarm in particular shouldn't simply be ignored or permanently silenced without determining why it activated.

It exists to tell you that the system may need attention.

Your Irrigation or Disposal Area Needs Attention Too

The tank gets most of the attention, but it's only part of an onsite wastewater system.

Once wastewater has been treated, it still needs to go somewhere.

Depending on your approved system, treated effluent may be distributed through an irrigation or other land application area.

Problems can develop if distribution equipment becomes damaged or blocked, vegetation changes significantly, the area becomes waterlogged or the disposal system is otherwise unable to function as intended.

If you notice persistent wet areas, strong odours or wastewater surfacing where it shouldn't, arrange an inspection.

Maintaining the treatment plant while ignoring the disposal area is only looking after half the system.

What You Put Down the Drain Matters

Some wastewater problems aren't caused by the equipment—they're caused by what enters the system.

An onsite wastewater treatment plant relies on processes that can be affected by inappropriate household products and waste.

As a general rule, avoid treating toilets and drains as rubbish bins.

Items such as wipes, sanitary products, nappies, cooking fats and oils don't belong in the system simply because they can physically fit down the drain.

You should also follow the recommendations provided for your particular wastewater system when choosing and using cleaning products and other household chemicals.

And despite what the packaging may suggest, “flushable” doesn't necessarily mean something belongs in your wastewater system.

Good habits inside the house can make life considerably easier for the equipment outside it.

Going Away? Don't Just Switch Everything Off

If you're heading away for several weeks, you might be tempted to switch off anything around the property that appears to be using electricity.

Be careful with your HSTP.

Treatment plants can rely on electrical equipment to maintain the processes occurring within the system. Turning equipment off without understanding the consequences can interfere with normal operation.

If you're unsure what should remain operating while you're away, check the instructions for your particular system or ask your wastewater service provider.

Buying a Home With a Septic Tank or HSTP?

If you've recently bought a rural or acreage property, wastewater maintenance should be near the top of your settling-in checklist.

Try to establish:

• What type of system is installed

• Approximately how old it is

• Who previously serviced it

• When it was last serviced

• Whether maintenance records are available

• When a septic tank was last pumped out

• Whether there have been recurring faults

• What ongoing servicing the system requires

If that information isn't available, arranging an inspection can give you a much better starting point.

You don't want your first introduction to the property's wastewater system to be an alarm going off on a Sunday morning.

Can Regular Servicing Save Money?

Preventative maintenance costs money, but so does replacing failed equipment.

The value of regular servicing is that smaller issues can potentially be identified before they contribute to larger failures.

A deteriorating component may be considerably easier to deal with during a scheduled service than after the entire system stops operating properly.

Good maintenance can also help protect the considerable investment you've already made in your wastewater infrastructure.

For homeowners who have recently paid for a new home sewerage treatment plant, maintaining it correctly from the beginning makes far more sense than neglecting it until problems appear.

Keep Your Wastewater Service Records

It's worth keeping copies of your wastewater servicing and maintenance records.

They provide a history of the system, including recurring problems and work that has previously been completed.

That information can be useful when diagnosing future faults and may also be valuable if you eventually sell the property.

If you've recently taken ownership of a home with an existing HSTP, ask the previous owner for any service documentation they have.

Knowing the history of the system is considerably better than starting from scratch.

Septic Tank & HSTP Servicing Across South East Queensland

Hughes Plumbing Contractors provides septic tank, HSTP and wastewater servicing and maintenance across South East Queensland.

Whether you have a traditional septic system, a home sewerage treatment plant or another onsite wastewater system, our team can help you understand what maintenance it requires and address problems when they arise.

Our broader wastewater capabilities also mean we can assist with more than scheduled servicing.

Hughes Plumbing Contractors provides wastewater system maintenance and repairs as well as septic tank and home sewerage treatment plant installations and replacements, supported by our plumbing, drainage and excavation capabilities.

So if an ageing system eventually needs more than another service, you already have a team that understands the bigger picture.

Not Sure When Your Wastewater System Was Last Serviced?

Don't wait for an alarm, sewage smell or wastewater backup to remind you.

If you own a property with a septic tank, HSTP, AWTS or home sewerage treatment plant, find out what maintenance schedule applies to your particular system and keep servicing up to date.

And if you've recently moved into a property and have no idea when it was last checked, that's a good reason to start now.

Contact Hughes Plumbing Contractors to discuss septic and wastewater system servicing, maintenance or repairs across South East Queensland.

Phone: 0406 288 142