Blocked Outside Drain

This is the most insidious and expensive cause. Tree and shrub roots seek water. Old clay or concrete drain pipes, which often have tiny cracks or loose joints, emit a steady stream of warm, nutrient-rich vapor. Roots penetrate these microscopic openings. Once inside, they thrive, expanding into thick, rope-like masses that fill the entire bore of the pipe. Unlike a debris blockage, root intrusion is a structural problem. Removing the roots without damaging the pipe is a delicate operation, and they will grow back unless the pipe is relined or replaced.

Sinks, baths, or toilets taking longer than usual to empty. blocked outside drain

Before you start, take these precautions: This is the most insidious and expensive cause

Run a specific appliance (e.g., the kitchen sink) and see if water appears in the nearest external gully. If water backs up instantly, the blockage is close. Roots penetrate these microscopic openings

The causes of an external drain blockage are as varied as the debris that flows into them. However, they generally fall into four categories: organic, mechanical, structural, and root intrusion.

Puddles or pooling surface water accumulating around the external gully grate.