A blocked kitchen sink, and what we do when someone rings with one.
The photograph shows the metal underside of a kitchen sink bowl and its waste outlet, with a white plastic waste pipe dropping through a junction towards the trap, which sits below the frame.
There is no blockage in this photograph. It was taken under a kitchen sink on one of our jobs, when we fitted a water filter there, and it shows the parts this post is about. The white shape at the right edge is the side of that unit and the red tube into the black clamp is its drain. The brass tee and blue-handled valve are on the supply, not the waste.
The signs
The bowl empties slowly at first, then the water stands in it.
It can gurgle or bubble as it empties, or when the washing machine pumps out, and there can be a smell under the sink.
Fat and grease
What usually blocks a kitchen sink is fat and grease. They set as they cool, and food scraps and coffee grounds catch in them, building up in the trap and the waste pipe after it.
Three places
Where the blockage sits decides the job, and it is usually in one of three places. It can be in the trap, just under the bowl. It can be further along the waste pipe, where it runs behind the units and out through the wall. Or it can be outside, where the kitchen waste goes into the drain. The rest of the house gives a clue to which. When the washing machine or dishwasher waste joins the sink’s waste and that water backs up into the sink as well, the blockage is past the point where the two join. When the other sinks, the bath and the toilet are slow too, it is further down the drain, and that is a drains job rather than a sink job. So what else is slow, and what else backs up into the sink, is the first thing we want to know, because it tells us where to start looking.
The call
On the call, we find where the blockage is and clear it there.
Then we look at why that run blocked, because a waste run that keeps blocking usually says something about the pipe: it is laid too flat, it has more bends than it needs, or a joint along it has sagged. Sometimes the answer is to re-run that section of pipe, which our drainage and pipework page covers.
Ring 07546 185778 and say how the sink is draining and whether anything else is slow too.
