High-pressure drain jetting

Some blockages are not a single plug of debris but a slow coating: grease from kitchens, scale on old iron, silt in a sagging pipe and fine roots at the joints. Rods can open a channel through it, but it closes again within weeks. High-pressure jetting scours the inside of the pipe clean. A hose fitted with a specialist nozzle is fed into the drain, and water at high pressure is directed backwards and outwards against the pipe walls, pulling the hose along and washing the debris downstream.

What jetting clears

• Fat, oil and grease, the main ingredient of fatbergs. By October 2025, Thames Water had cleared 14,810 fat, oil and grease blockages that year alone.
• Wet wipes and rag, which bind with grease into solid masses. In 2017 a fatberg in a Victorian sewer under Whitechapel Road was about 250 metres long and weighed around 130 tonnes.
• Scale and sludge coating the inside of older cast-iron and clay pipes.
• Silt and grit that settle where a pipe has sagged or a joint has dropped.
• Fine roots, cut back with a rotating root-cutting head.

Worth knowing: Restaurants, hotels and blocks of flats feed a lot of grease into the drains, which is why shared drain runs in places like Mayfair, Marylebone and Bayswater can coat up quickly. Never pour cooking fat down a sink: let it cool and put it in the bin.

Choosing the right pressure

Jetting is powerful, and the same pressure that clears a modern plastic drain can damage an old, fragile pipe. Before we start, we find out what the drain is made of and what state it is in, often with a CCTV drain survey, then choose the nozzle and pressure to suit. Old clay, cast iron and pipes with known cracks get a gentler approach. If a pipe is too badly damaged to jet safely, we tell you and talk about repair instead.

After the jet

When the drain runs freely, we run water through it to check that it flows away properly. Where the problem keeps coming back, a camera survey after jetting shows the clean pipe clearly, including any cracks, roots or dips that caused the build-up in the first place.

Shared drains and responsibility

In terraces and converted houses, one drain often serves several homes. Since October 2011, most drains shared with other properties, and lateral drains outside your boundary, have been Thames Water’s responsibility. We tell you which part of the system the problem was in, so you know who should pay.

To book jetting, or if a drain is blocked right now, call 07862 142953 or WhatsApp us a photo. For an immediate blockage, see drain unblocking.