Blocked Drains in Christchurch: Common Causes and Real Fixes

Tree roots

The number one cause on older sections in St Albans, Merivale, Beckenham and Riccarton. Roots find the tiny gap at an earthenware joint, drink from it, then grow into a mat that catches everything else.

Cutting the roots out clears the drain, but they grow back within a year or two. A camera inspection tells you whether the joint needs relining or a section replaced.

Silt, sand and ground movement

Liquefaction pushed silt into a lot of eastern Christchurch drains, and settlement left some lines with a belly or a stepped joint where waste now sits instead of flowing. Symptoms are slow drainage that keeps returning after each clear.

Fat, grease and food waste

Cooking fat goes down warm and sets hard in the cold pipe run under the house. Combined with coffee grounds and rice it makes a plug that no plunger will shift.

Wipes and hygiene products

'Flushable' wipes don't break down. They snag on any rough joint and then catch paper behind them. Only the three Ps go down a toilet: pee, poo and paper.

What you can try yourself

• Plunge a single blocked fixture with the overflow taped over
• Pour a kettle of hot (not boiling) water and dish soap down a slow kitchen sink
• Clean out the gully trap outside for leaves and debris
• Clear the shower or basin waste of hair with a drain snake

When to call a drainlayer

• More than one fixture is backing up at once
• Waste is coming up the gully trap or shower
• The same drain blocks every few months
• You can smell sewer gas inside or in the yard
• There's a wet, sunken or unusually green patch in the lawn

How we clear it

We start with a mechanical eel or high-pressure water jetter to get flow back, then put a CCTV camera down the line to find out why it blocked. You see the footage yourself, and if the pipe needs work we quote it in writing before anything starts.

Frequently asked questions