High pressure jetting: what it clears, and when it is the wrong tool
Jetting clears far more than rodding ever will. It also cannot fix a pipe that has already failed, and used on the wrong drain it makes things worse.
What it actually is
Water at high pressure, delivered through a hose with a nozzle that fires backwards as well as forwards. The rear jets pull the hose along the pipe; the forward jet cuts the obstruction. Pressure and nozzle are chosen for the pipe, which is the part that matters.
Against rodding, the difference is coverage. Rods punch a hole through a blockage. Jetting scours the full bore, so what comes back is a clean pipe rather than a channel through the same deposit that will close again in weeks.
What it clears well
- Fat and grease lining the pipe wall, the commonest cause in kitchens and behind restaurants
- Silt and scale in runs with poor fall
- Fine root hair at joints, cut back to the pipe wall
- Wipes and debris packed at a bend
On a commercial kitchen run, scheduled jetting is the difference between planned maintenance and a Friday night closure. See grease management.
What it cannot do
Jetting clears. It does not repair. If the pipe is cracked, displaced, or collapsed, jetting will get the flow moving and the problem will return, because the defect is still there and still catching debris.
Worse, on already-fragile pipework, high pressure can open a hairline crack into a hole. This is why we survey rather than guess on older clay, and why a contractor who jets a repeat blockage for the third time without ever putting a camera down is selling you the same hour over and over. The tell is in blocked or broken.
Roots are a partial case: jetting removes what is inside the pipe but not what is outside it, and they grow back through the same joint. Permanent answers are in tree roots in drains.
Where care matters
Pitch fibre pipe, common in mid-century housing, deforms under heat and pressure. Lead and older cast iron need a lighter touch. Pumped systems need the discharge run checked rather than blasted. And in a shared run, jetting from the wrong end pushes the problem into a neighbour’s property, which is a different kind of expensive.
None of that is a reason to avoid jetting. It is a reason to know what the pipe is before turning the machine on.
What to expect on the day
Access through an inspection chamber where possible rather than through the property. A working session rather than a two-minute fix: cutting fat back properly takes time. And a camera afterwards, so you can see the pipe you have paid to clear.
We include that last step because it is the only way to tell whether the job is finished or the drain is due back. Drain unblocking, with coverage in Lambeth, Ealing and Greenwich.
We work these streets regularly. More detail on CCTV drain surveys in Lambeth and blocked toilets in Lambeth.