The free diy home improvement guide with answers to your questions on a wide range of do it yourself projects.


Blocked waste pipe

Waste pipe blockages

The water from the waste outlet in sinks and baths etc should drain reasonably quickly and freely. If the flow becomes slow, it indicates a blockage beginning to build somewhere in the pipework.

Since these waste pipes have to deal with everything from leftover bits of food to strands of hair, it is hardly surprising that they block up from time to time.

Drain cleaner or unblocker

You can try using a proprietary drain cleaner to prevent the build up of such blockages. Be sure to follow the instructions and safety precautions carefully as they are caustic. They should not be left to act for an excessive time.

Using a plunger

using a plungerA plunger is a simple device, but very effective if used correctly. There are several types available including pump action ones. . Smear petroleum jelly around the base of the plunger – this helps seal it against the bottom of the bowl. Place the plunger over the outlet and run the water so that there is enough in the bowl to cover the base of it. Now, holding a wet cloth over the overflow, pump the plunger several times. Remove it and see if it’s worked. Repeat as necessary.

Bloked waste trap

removing waste trapAlthough the last method can be very effective, the action can just push the blockage along the pipe a little, but may not release it.

Frequently the blockage will be in the trap beneath the sink. The quickest way to remove it is to clean out the trap. Place a washing-up bowl under the trap to catch the water.

Remember not to switch on the taps again until it’s replaced.
Unscrew the two ends of the trap and ease it out. Clear any debris from it. If this is where the blockage was, you will clearly see it. Reassemble the trap and check the flow of waste water again.

Rod out the blockage

using a rod to clear the wasteIf the blockage has not been removed, it will be necessary to ‘rod’ the pipe out. This can be done from an access cap, which will have been fitted at any sharp junctions in the waste pipe if it was installed by a thoughtful plumber. Failing this, you can remove the trap again and access the pipe run from here. Have a bucket standing by and protect the area beneath. A blocked pipe may be holding a fair bit of dirty water.

If the blockage is near, it is often possible to remove it using a straightened wire coat hanger with a small hook shaped at the end.

Drain rods

More awkward to reach blockages will require the use of a narrow gauge drain rod. This is usually a long length of wire on a reel with a hook set on the end. It is pushed into the pipe until it reaches the obstruction and then twisted to release it.

Once cleared, replace the trap or access cover and test the flow of waste water.


clearing a gulleyThe gulley can easily become blocked with a build up of leaves and other debris.

Remove the grate. If you have use of a rodding auger, this can be used as for rodding a soil pipe by inserting it and turning the handle.

If you do not have one, protect your hands with thick rubber gloves before starting. There is every possibility of coming across sharp objects.
Remove as much water as you can using an old plastic container. Then reach into the gulley, which is like a giant version of the trap under your sink. Fish out the debris until the bend is clear. Flush through with running water before replacing the grate.