Signs your septic tank is failing

Slow, gurgling or backing-up drains

If sinks, showers and toilets drain slowly across the whole house, or gurgle when water runs elsewhere, the problem is usually further down the line than a single blocked pipe. It can mean the tank is full, the outlet is blocked, or the drainage field can't take any more water.

Smells in the garden or near the tank

A faint smell around the covers on a warm day isn't unusual, but a persistent sewage smell in the garden often means effluent is reaching the surface or a cover or pipe is damaged.

Wet, mushy ground or unusually green grass

This is one of the most common signs of a failing drainage field. When the soil around the trenches clogs up, effluent rises towards the surface instead of soaking away, leaving boggy ground or strips of lush grass. It's often a drainage field problem rather than a tank problem.

Needing to empty the tank more often

If the tank fills much faster than it used to, the outlet or the drainage field may not be taking water away. Emptying more often treats the symptom, not the cause.

Cracks, leaks or an old brick tank

Older brick or single-chamber tanks can crack or leak with age. Under the general binding rules, a system that leaks, is blocked or smells must be repaired or replaced.

What to do next

Note what you've seen and when, take a few photos of the covers and any wet ground, and get the whole system looked at. The fix might be a repair, a new drainage field, a replacement tank or an upgrade to a treatment plant. It depends on what's actually failing.