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 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 arranges 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. We arrange servicing and alarm call-outs across Port Macquarie-Hastings, with all mechanical and electrical work carried out by appropriately qualified technicians and any plumbing repairs by licensed plumbers.