Something's wrong with your septic. Start here.
A septic system almost never fails without warning — it sends signals first, and each signal points somewhere different. A smell near one basin is usually a $0 fix; wet ground over the trenches can be a five-figure one. Pick the symptom that matches what you're seeing and the guide will walk you through what it means, what it costs, and when to call someone. If you have more than one symptom, or you're not sure, start with the signs-of-failure guide — it covers all five warning signs in order of urgency.
Pick your symptom
It smells
Rotten-egg odour indoors, near the tank or hanging over the yard — the location of the smell tells you the cause.
Slow drains or gurgling
One slow basin is plumbing. Every drain slow, with gurgling toilets, is the septic system. How to tell which.
Wet ground or overflow
Soggy patches, pooling effluent or an overflowing tank. This one is a health risk — act today, not next week.
Is my system failing?
Not sure, or seeing several symptoms at once? The five warning signs of failure, ranked by urgency.
Repair or replace?
Trench rejuvenation, new trenches or a full system upgrade — realistic costs and when council approval kicks in.
Nothing's wrong — yet
The cheapest problem is the one you prevent. Pump-out schedules and maintenance that keep you off this page.
| What you're seeing | Urgency | Likely first step |
|---|---|---|
| Occasional smell, one location | Monitor | Check floor-waste traps and the vent; often free |
| Whole house draining slowly | This week | Pump-out and outlet-filter check, $300–$600 |
| Effluent pooling on the surface | Today | Fence it off, cut water use, call a licensed contractor |
| Sewage backing up indoors | Now | Stop using water; emergency pump-out same day |
Common questions
Who do I call first — a plumber or a septic contractor?
If the problem is inside the house and only affects one fixture, a plumber. If every drain is affected, or the problem is at the tank or in the yard, you want a septic/wastewater contractor — they carry the pump-out truck and the diagnostic experience a general plumber may not.
Will the council find out I have a problem?
Possibly — many councils run inspection programs, and neighbours can complain about smells or runoff. Acting quickly works in your favour: councils pursue owners who ignore surfacing effluent, not owners who are already fixing it. In Victoria you're actually required to notify council of a failing system.
How much do septic repairs cost?
Anywhere from a $300–$600 pump-out to $20,000+ for a full system replacement. The symptom guides on this page narrow down where you likely sit on that range, and the repair-or-replace guide compares the options.
Want a professional diagnosis?
Describe the symptom and your postcode — accredited local repairers will call back with quotes, usually starting with an inspection.