How to Clear Blocked Drains



No matter how the drains run, there is a set procedure for dealing with clogged drains and blockages:

♦ Establish that the problem isn’t caused by a blocked appliance trap or waste pipe.

♦ Lift the manhole (inspection chamber) cover nearest the house (See Problem Solver – Blocked Drains).

♦ If the manhole is full of effluent, you know the blockage is downstream of this point. Start rodding here, away from the house.

If this doesn’t work, move to the next manhole, If this is full too, rod the downstream end; otherwise, rod back up towards the full manhole to attack the blockage from the other side.

♦ If the manhole is empty, you know the blockage is upstream. Get a helper to try various taps and appliances around the house while you watch the manhole to see which pipes are blocked. You can then rod the affected pipe.


Safe and clean

Never leave a manhole uncovered when you aren’t there, and erect a makeshift barrier if you have to leave it unattended.

After clearing the blockage, flush all pipes and manholes with a hose. Wash all equipment in disinfectant and give yourself a good scrub-down.


Trade Tip

Water power

"Don’t underestimate the power of hydraulics — in this case the water trapped in the drain — to shift blockages in clogged drains. Often you can harness this power without much difficulty using only a couple of rods and a rubber disc attachment.

Push the rod assembly into the drain at any convenient point upstream of the blockage, then pump vigorously backwards and forwards. In many cases the pressure built up by the water already in the drain will be enough to clear the blockage. Make sure, though, that you hold on tightly to the rods, otherwise the suction effect created by the pumping will draw them down into the pipe."


If the blockage can’t be cleared by pumping (see Trade Tip on Use of Drain Rods), try physically shifting it using several rods screwed together. Which attachment you fit is largely a matter of trial and error, Start with a rubber disc unless you have reason to think the problem is caused by roots (in which case fit an auger).

using drain rods

Keep turning the rods clockwise as you push them down into the drain, so that there’s no risk of them unscrewing. When working without an attachment, count the rods down and count them back up again to double check that none are left behind.

Full manholes

A manhole full of effluent is a daunting sight, but normally there’s no need to empty it before rodding. You know that there is only one outlet hole, so just keep pushing the rods towards the downstream end.

Keep turning rods in a clockwise direction all the time they are in the drain to stop them unscrewing. When you meet resistance, push and turn at the same time to dislodge the debris.

If the manhole is full, insert the rods ‘blind’ and push towards the downstream end. The channels mortared into the base of the manhole will guide the rods towards the outlet hole.

Tree roots won’t respond to a rubber disc: fit a cutting attachment instead, or hire a purpose-designed root cutting auger which can be powered from an extension lead.

24. May 2011 by admin
Categories: Drains, Plumbing | Tags: , | Comments Off on How to Clear Blocked Drains


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