Hastings Septic Co treats an AWTS alarm as an urgent servicing matter: a flashing light or buzzer almost always means the blower, irrigation pump or a float switch has stopped working, or the system has lost power, and the fix is a technician’s visit, not a DIY repair. Reduce water use, stay off the irrigation area, and book a service call promptly.
Below is what the alarm is actually telling you, what’s safe to check yourself while you wait, and what to leave strictly to a technician.
Why is my AWTS alarm going off?
An aerated wastewater treatment system (AWTS) is a small mechanical treatment plant, not a passive tank: it only keeps producing clean, irrigation-quality effluent while its blower, pumps and disinfection stage are all working. The alarm exists to tell you the moment one of those parts stops. If you’re not sure whether your property has an AWTS or a conventional septic tank and trenches, our septic vs aerated wastewater system guide explains the difference, and it matters here because only aerated systems carry this kind of electronic alarm.
In practice, an AWTS alarm is almost always one of four things:
- The air pump or blower has stopped or is failing. This is the single most common AWTS fault. The blower feeds oxygen to the bacteria doing the treatment work, and those bacteria start dying within days of the airflow stopping.
- The irrigation pump or a float switch has failed, so wastewater is banking up in a chamber instead of moving through to irrigation.
- The system has lost power, at the wall, at a switchboard, or through a dislodged plug or lead.
- A genuine electrical or control-panel fault, less common, but why the alarm and control panel are checked at every scheduled service.
What do the different alarm signals mean?
Panels vary by brand, so treat this as a general guide rather than a universal code, and check the brand printed on your control box lid if you want to match it exactly. As a general pattern across most domestic AWTS panels in this region:
| Alarm signal | What it usually means | Urgency |
|---|---|---|
| Steady light, no buzzer | A fault has been logged, possibly an earlier event the panel is still holding | Book a service soon |
| Flashing light plus an audible buzzer | An active fault, most often the blower or a pump has stopped | Urgent, act today |
| Continuous buzzer with the light on | High water level in a chamber, or an unacknowledged fault | Urgent |
| No lights at all on the control box | Power supply to the unit has been interrupted | Check the power supply first |
| Light on but you’re not sure if it’s new | Don’t assume it’s old news; treat any alarm you can’t explain as current | Ask a technician |
Whatever the signal, the reliable next step is the same: note exactly what the light and buzzer are doing, then book a service rather than guessing.
What does each alarm light mean?
AWTS brands vary in how they present alarm states. Common brands in the Port Macquarie area include Envirocycle, Biocycle, Orenco, Aquafast, BioMaxx and Fuji Clean, and each has its own panel design, but the underlying alarm categories are consistent: power supply, high water level, motor or aerator, pump, disinfection, and general fault. Your system’s manual, usually clipped inside the control panel lid, has the specific meanings for your model.
Green light only: normal operation
A solid green light or LED on most panels means the system is powered and operating normally. No action required. If the green light is never on, you have a power problem rather than a treatment problem.
No lights at all: power loss
A completely dark panel means the unit has no power, usually a tripped breaker at the switchboard, a property-wide outage, a damaged supply cable, or a failed power supply board. Check the switchboard for a breaker labelled “Septic”, “AWTS” or “Pumps” and reset it once. If it trips again immediately there is a short or an overload in the wiring, which is work for an electrician, not a second reset. A power outage lasting more than 24 to 48 hours lets the aeration chamber go anaerobic, so tell your service provider after any extended outage so the system can be checked for recovery.
Red light plus buzzer: high water level
The most common alarm. A float switch has detected liquid above its normal operating range, which means the system is taking in liquid faster than it can treat and discharge it. Usual causes are a saturated irrigation area after heavy rain, a failed irrigation pump, blocked drip emitters, or a genuine spike in input from extra guests or a water leak.
Reduce water use immediately: no laundry, short showers, minimal flushing. Look at the irrigation area without walking on it. If the ground is saturated after rain, the alarm may clear within 24 to 48 hours as it drains. If it persists beyond 48 hours of dry weather, or effluent is surfacing, it needs a service call. If sewage is backing up toward the house, treat it as an emergency.
Red light, no buzzer: aerator or motor fault
The aerator motor has failed or is drawing the wrong current. The aerator is the core of the system; without it the treatment goes anaerobic within days and effluent quality drops. This is not something to monitor. Minimise wastewater input and book the service call.
Yellow or amber light: chlorine low or UV lamp alert
On chlorine systems this usually means the tablet supply is depleted. On UV systems it usually means the lamp is near end of life or has failed. Chlorine is restocked at every quarterly service, so seeing this between services means either unusually high demand or a missed service, and a mid-cycle refill is worth arranging. Without disinfection the effluent does not meet the pathogen reduction specified in your council approval.
Flashing green or alternating lights: pump running
On some models this simply indicates the dosing pump is running, which is normal operation rather than an alarm. A pump that appears to run continuously without stopping can indicate a stuck timer or controller, worth raising at the next service.
All lights on at once
On some models this indicates a controller or logic board fault. Cycle the power off for 30 seconds and back on. If it persists, it needs a service call.
Alarm response quick reference
| Alarm condition | Likely cause | Action |
|---|---|---|
| No lights at all | No power | Check breaker, book a service if it persists |
| Red light plus buzzer | High water level in a chamber | Reduce use, check irrigation, book a service if it persists 48 hours |
| Red light, no buzzer | Motor or aerator fault | Book a service call |
| Amber or yellow light | Low chlorine or UV fault | Arrange a mid-cycle visit |
| Alarm after heavy rain | Saturated irrigation area | Reduce use, wait for the ground to drain |
| Alarm after power outage | Aeration chamber going anaerobic | Notify the service provider |
Alarms after guest departures or high-use periods
On a holiday rental, an alarm just after a full house is not unusual. Laundry, multiple showers and repeated dishwasher cycles can load a system to its design limit, and if the irrigation area was already moist that is what tips it over. Our guide to managing septic systems in holiday rental properties covers the preventive side.
When to call for emergency assistance
Treat it as an emergency rather than a next-business-day job when sewage is backing up inside the house, sewage or foul water is pooling above the irrigation area, reducing water use is not containing the situation, the alarm has run more than 48 hours with no improvement, or the unit has been submerged in floodwater. Urgent enquiries for emergency septic and AWTS pump-outs come from across Port Macquarie, Wauchope, Lake Cathie, the Camden Haven and surrounding areas.
What can I safely check before calling for a service?
There’s a short list of things a homeowner can safely look at without opening the unit or touching electrical components:
- Check the power. Has a breaker tripped at the switchboard? Has a lead near the control box been knocked loose, for instance by mowing or gardening close to it?
- Look, don’t lift. Is there any pooling, odour or obvious wetness around the irrigation area? Note it, but don’t approach it closely or let kids or pets near it.
- Note the alarm behaviour. Steady or flashing light, buzzer on or off, and roughly when it started. This detail speeds up diagnosis considerably.
- Ease off water use. Fewer loads of washing, shorter showers, and holding off on the dishwasher reduce the load on a system that isn’t treating properly right now.
That’s the full list. Everything past this point, opening the unit, testing the blower, replacing a float switch or diaphragm, is a job for an appropriately qualified technician.
What should I never do when the alarm is on?
A few things genuinely make the situation worse:
- Don’t switch the system off at the power point to “silence” it. The blower is meant to run continuously, and cutting power doesn’t fix a fault, it just adds a second problem on top of the first.
- Don’t lift tank or chamber lids and lean in. Septic gases are dangerous in confined spaces, and this applies to AWTS chambers as much as conventional tanks. Leave that to the operator.
- Don’t rely on additives or “boost” products to sort out a treatment problem. They don’t fix a broken pump or blower, and there’s no substitute for the mechanical repair actually being made.
- Don’t keep muting the buzzer indefinitely and carrying on as normal. Many panels let you silence the audible alarm; that stops the noise, it doesn’t stop the fault.
Does a power outage set off the AWTS alarm?
Yes, generally. The blower stops the instant power is cut, and most panels raise an alarm on loss of power the same way they do for a mechanical fault. Once power returns, some systems recover on their own as the blower restarts; others need the alarm manually acknowledged or reset. Either way, if the outage ran for more than a day or so, especially after a storm, it’s worth getting the system checked: the treatment bacteria can start dying within days of the blower being off, and a quick service visit confirms the system has genuinely recovered rather than assuming it has.
What does it cost to fix an AWTS alarm fault?
Most alarm faults are a straightforward part replacement if caught early, and the cost sits within the same range as any other AWTS service call. Using our published AWTS servicing figures for the Port Macquarie-Hastings region as a guide:
| Service type | Indicative price range* |
|---|---|
| Single AWTS service visit (most alarm call-outs) | $180-$330 |
| Catch-up service on a neglected or long-unserviced system | $250-$450 |
| Annual servicing agreement (typically 4 visits) | $650-$1,200 |
| Sludge pump-out of AWTS chambers (when due) | $400-$750 |
*Indicative guide only. Replacement parts, diaphragm kits, air pumps, irrigation pumps, floats and alarm components, are always quoted separately before fitting, and travel to the outer villages can move the figure. Our septic pump-out cost guide covers the wider pricing picture across all our services, including how tank size, access and urgency move a price.
How does regular servicing stop alarms happening in the first place?
Hastings Septic Co takes enquiries for AWTS servicing on a quarterly schedule for most systems in NSW, though the exact interval is set by your system’s accreditation and your council approval conditions, so check yours with Port Macquarie-Hastings Council if you’re unsure. A routine AWTS service checks the blower, irrigation pump, float switches and disinfection stage before any of them fail outright, which is exactly the mechanism that prevents most alarm events. Systems that alarm “out of nowhere” have very often gone well past due on servicing, sometimes years, which is why a catch-up service is priced separately from a routine one: there’s usually more to find and reset before the schedule can run cleanly again.
Why do alarms seem to trigger more at some properties than others?
Occupancy is the biggest swing factor we see. Holiday rentals around Lake Cathie, Bonny Hills and the wider Lake Cathie corridor can jump from empty to a full house of guests for weeks at a stretch over summer, and that kind of load swing is hard on a system sized for ordinary household use. A system on a documented service schedule generally handles it; one that’s overdue is far more likely to alarm right in the middle of a booking. If you manage a holiday letting on an AWTS, aligning the service visit to just before your peak season is a genuinely useful habit, not just a nice-to-have.
AWTS Alarm FAQs
What’s the most common reason an AWTS alarm goes off?
A failed or failing air pump (blower) is the most common cause. It feeds oxygen to the bacteria doing the treatment work, and when it stops, the alarm activates because the system can no longer treat wastewater properly. Irrigation pump and float switch faults are the next most common causes.
Can I turn the alarm off myself?
You can usually mute the audible buzzer on most panels, but that silences the noise, it doesn’t fix whatever triggered it. Never switch the whole unit off at the power point: the blower is designed to run continuously, and cutting its power creates a second fault on top of the first.
How long can I leave the system before it’s a problem?
Treat any unexplained alarm as urgent rather than something to monitor for a few days. Treatment bacteria can start dying within days of the blower stopping, and the longer a fault runs, the more likely it is that untreated effluent reaches the irrigation area, which is exactly what the alarm exists to prevent.
Does the alarm mean sewage is overflowing?
Not usually, and often it doesn’t. Most alarms are a mechanical fault (a stopped pump or blower) rather than an overflow. That said, if you notice pooling, odour or wetness around the irrigation area as well as the alarm, keep people and pets away from that area and treat the call as urgent.
Will a service visit definitely fix the alarm?
In most cases, yes: a technician runs through the blower, pump, float switches and electrical function, finds the fault, and either resolves it on the spot or quotes any replacement part needed. Occasionally a system that’s been neglected for a long time needs a catch-up visit first to get it back to a baseline before the alarm clears for good.
What if the alarm keeps going off after a repair?
Tell us straight away if a fault recurs shortly after a service. It’s usually either a different component failing (rather than the same one), or an underlying issue like sustained high water use that keeps tripping a float switch. Either way, a repeat alarm is worth a follow-up visit rather than muting and waiting it out.
Get your AWTS alarm sorted properly
An alarm that’s flashing right now doesn’t need guesswork, it needs a technician who can tell you exactly what’s failed and what it takes to fix it. Send your suburb, the system brand from the control box lid, and what the light and buzzer are doing, and get a free quote. Servicing and alarm call-outs across Port Macquarie-Hastings involve mechanical and electrical work for appropriately qualified technicians, and any plumbing repairs are work for a licensed plumber.