Most blockages fall into one of two categories. Knowing which one helps you choose the right tool:
are designed to handle rainwater. These connect to gutter downpipes, driveway grates, and land drains. In an ideal world, this water flows directly to a soakaway, a local watercourse, or a separate surface water sewer. Blockages here are typically organic (leaves, moss) or silt.
Sinks, baths, or toilets taking longer than usual to empty. blocked outside drain
For a surface water drain (leaves/silt):
You might diligently wipe pans before washing, but the small amount of grease that goes down the kitchen sink doesn't disappear. It travels through your internal pipes and hits the cold, external drain. There, it solidifies like candle wax. Over months, this waxy buildup catches other debris—food particles, soap flakes, and hair. The result is a “fatberg” in miniature. In foul drains, this creates a sticky, concrete-like obstruction that requires hydro-jetting to remove. Most blockages fall into one of two categories
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.
The Ultimate Guide to Unblocking Your Outside Drain An outside drain blockage is more than just a nuisance—it can lead to standing water, foul smells, and even serious property damage if left untreated. Whether it's a buildup of autumn leaves or a more stubborn kitchen grease clog, knowing how to spot and fix the issue early can save you significant time and money. Telltale Signs of a Blockage Before you start digging, look for these common red flags: In an ideal world, this water flows directly
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.
Gurgling or bubbling sounds coming from your pipes after using water.