Septic problems: start from what you're seeing
Most septic problems aren't a failed drain field. Each page works through the cheap causes before the expensive one.
The short answer
The fastest way to narrow a septic problem is to ask where the evidence is. Slow drains and backups in the house point to a full tank, a clogged line or a blocked filter. An alarm points to the pump. Wet ground or a smell over the drain field, especially in dry weather, points to the field — the one problem that costs thousands.
In this section
Quick reference: symptom to likely cause
A starting point, not a diagnosis. The pages above explain how to tell the causes apart.
| What you notice | Most likely | Who to call |
|---|---|---|
| One slow drain | A clog in that fixture | Nobody yet — plunger or snake |
| Smell in one room | A dry trap or toilet wax ring | Nobody yet — refill traps first |
| Several slow drains, gurgling | A full tank or blocked filter | A septic pumper |
| Backup right after pumping | A clogged line from the house, or the field | A plumber for the line; an inspector for the field |
| Alarm sounding | Pump, float, breaker or heavy rain | A septic service company |
| Wet, smelly ground over the field | A failing or saturated field | A septic inspector |
| Problems only after heavy rain | Saturated soil or leaking lids | Wait for dry weather; check lids and gutters |
Work from cheapest to most expensive
The costly mistakes nearly all come from skipping steps: quoting a $4,700 – $12,400 drain field when the problem was a $50 – $350 filter or a $150 – $500 clog. Pump the tank, check the baffles, filter and inlet line, and only then investigate the field.
The exception is sewage in the house or on the surface. That's a health problem first: stop using water and keep people and pets away before working out the cause.