Drain Unblocking and Cleaning

• Sinks and basins: Usually fat and food in kitchen wastes, or hair and soap in bathroom basins. Often the trap or the short waste pipe to the outside.
• Toilets: Wipes, sanitary products and too much paper, either in the pan or further down in the soil pipe.
• Baths and showers: Hair and soap scum, which build up gradually in the trap and waste.
• Outside gullies: The open grids by the back door where kitchen wastes and downpipes discharge. Leaves, silt and fat collect here.
• Inspection chambers and underground drains: The pipes under the garden, path or driveway, reached through the manhole covers.
• Soil stacks and rainwater pipes: The vertical pipes on or inside the building, which can block where they bend at the bottom.

For a gully or the first inspection chamber, there are a few things you can safely try yourself:

1. 1

   Wear rubber gloves and keep children and pets away. Waste water carries bacteria.

2. 2

   Clear the gully grid: lift it off and scoop out leaves, silt and fat by hand. Then pour a bucket of water through to check it drains.

3. 3

   Lift the chamber covers: a flat spade or screwdriver under the edge usually works. Lift with your legs, as cast-iron covers are heavy. Find the full chamber that is nearest the road; the blockage is usually just downstream of it.

4. 4

   Rod the drain: push drain rods along the outlet of the full chamber, and turn them clockwise only. Turning them anticlockwise can unscrew the rods and leave a length stuck in the drain.

5. 5

   Flush through: once the water drops, run a hose or a few buckets of water to check that it flows freely.

Stop if the rods will not get through, if the chamber is deep or in poor condition, or if the blockage returns. Many older houses also have an interceptor trap in the last chamber before the sewer. If its rodding stopper has fallen out, it can cause repeat blockages that rods alone will not fix.

We start with the simplest method that will clear the blockage:

• Plungers and hand tools for traps, sinks, basins and toilets.
• Drain rods with different heads to push through, break up or pull back a blockage in the underground drain.
• Electro-mechanical drain machines, which rotate a flexible cable through the pipe to cut through hard blockages in smaller pipes.
• High-pressure water jetting, which scours fat, scale and silt from the pipe walls as well as clearing the blockage. Our drain jetting page explains how it works and when it is not suitable.

After clearing, we run water through each chamber to confirm the flow. If the drain has blocked before, or we find debris that suggests damage, such as broken pipe, soil or roots, we recommend a CCTV drain survey to see inside the pipe before more money is spent.

A one-off blockage is usually something that went down the drain. A drain that keeps blocking usually has an underlying cause:

• Fat and grease: It sets as it cools and lines the pipe, narrowing it a little more each time.
• Wet wipes: Even those labelled "flushable" do not break down like toilet paper, and they snag on joints and roots.
• Roots: Fine roots enter through cracked pipes and loose joints, then grow into a mat that catches waste.
• Damaged or collapsed pipes: A cracked, displaced or sagging section catches waste, and a collapse can block the drain completely.

Roots and fat can be cut out and washed away, but they will return if the pipe itself is damaged. Cracked and root-damaged drains can often be fixed without digging through our drain repairs and lining service. A collapsed section needs drain installation and replacement.

Occasionally a partial blockage of soft material, such as toilet paper, will break down and wash through. Most blockages do not clear on their own: fat hardens, wipes and hair bind together, and roots keep growing. A slow drain is a warning that the pipe is already narrowing, so it is best dealt with before it blocks completely and backs up.

Avoid pouring chemical drain cleaners into a fully blocked drain (see the FAQs below).