Septic Alarm Light On — What the Red or Yellow Light Means
If your aerobic septic system is showing a red or yellow alarm light, don't ignore it. Alarm lights indicate something in your system needs attention — sometimes urgently, sometimes within a few days. This guide explains what the lights typically mean and what to do next.
What the Alarm Lights Usually Mean
Red Light (Alarm)
A red light signals an active alarm condition. Common causes include high water levels in a tank (pump failure), complete air compressor failure, or a float stuck in the wrong position. Reduce water use and request service promptly.
Yellow Light (Warning)
A yellow light often indicates a warning rather than a full alarm — low chlorine, a minor sensor issue, or a component nearing the end of its service life. Schedule a maintenance or service call within a few days.
Common Causes of Septic Alarms
- Air pump / compressor failure — the most common cause of red alarms
- Water pump failure — pump not moving water between tanks
- Float switch stuck or malfunctioning
- High water levels in the trash tank or pump tank after heavy rain
- Clogged pump screen restricting flow
- Electrical fault in the control panel
- Low chlorine levels triggering a warning light
What Information to Have Ready Before Calling
When you contact a provider, having this information ready will help them respond faster:
- The brand and model of your control panel if visible
- Whether the alarm is red or yellow (or both)
- How long the alarm has been active
- Whether there's an audible alarm sound
- Any recent changes — more people in the house, heavy rain, power outage
- When your system was last serviced
Related Pages
Septic Alarm FAQs
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