Clearing a Clogged Sink



Sink traps — sometimes called ‘U’ bends — are sections of waste pipe which remain permanently filled with water to stop smells filtering back through the drains. Every water-holding plumbing fitting has one, usually connected directly to the waste outlet, but sometimes further along the waste pipe itself.

clear a clogged sinkUnfortunately, traps are also a natural place for waste particles to collect. Better design and the use of plastic have helped to make modern traps smoother — and therefore less likely to block and and get clogged up — than the old metal type. But no amount of good design can eliminate the problem altogether. In the end, it’s up to the user to be careful about what is washed down the drain — and that’s easier said than done.

Even so, it pays to be aware of the kinds of things which cause trap blockages, not least because this knowledge can help you decide how to deal with the problem. The worst offenders, in order, are:

♦ Tea leaves and coffee grounds.

♦ Meat fats washed away with washing-up liquid.

♦ Food particles — rice, peelings.

♦ Household fillers and plaster.

♦ Hair (particularly in baths).

Often, it’s possible to clear a clogged sink trap without resorting to dismantling it (see Shifting Blockages from Clogged Sinks). But stubborn blockages and obstructions further down the waste pipe may call for more drastic action.


Trade Tip

Tell tale signs

"Blocked and clogged sink traps don’t always occur suddenly — often there is a gradual build-up of debris which causes the water to drain away increasingly slowly. This is the time to act, before you have the added problem of getting rid of the waste water."



Plastic ‘U’ bends have an easy flow line, so are less likely to block —though if they do, they are quickly dismantled. The two sections are joined by threaded unions.

Metal ‘U’ bends of lead or copper are difficult to dismantle and so often have a small threaded clearing eye. Lead traps are easily damaged, and there’s a risk of the eye snapping off.

Plastic bottle traps are more compact than ‘U’ bends, making them the natural choice for basins. The lower half unscrews for clearing, or has a push-and-turn bayonet fitting.

Straight-through traps are mostly found behind basin pedestals where space is limited. The tight bends are a natural place for blockages, so there is usually a clearing eye in the top.

Low level bath traps are used where a deeper ‘U’ bend or bottle trap would be impossible to fit, and some models have an integral overflow. The horizontal section is prone to collect hair.

Running traps are mostly found in shower wastes where access beneath the tray is restricted. A common cause of blockages is that the trap is fitted the wrong way round.

24. May 2011 by admin
Categories: Plumbing, Sinks | Tags: , | Comments Off on Clearing a Clogged Sink


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