Your kitchen sink is used for all sorts of purposes, not just washing up. You likely strain vegetables over it, clean paint brushes in it, and scrub stained clothes in it before putting them into the washing machine. Sometimes, sinks are also used inappropriately for waste disposal. It is often tempting to throw away old paints and cooking fat by simply pouring them into your sink, especially when everything appears to flow away satisfactorily. As any plumber will tell you, the trouble with this is that it can lead to your sink's wastewater pipe blocking up. What can you do if this is the case?
Use a Pipe-Cleaning Gel
One of the most common ways of dealing with a slow-draining sink is to put a liquid or gel into the plughole which will clear a path. The majority of these products use an alkali among their ingredients which eats away at any solidified material which is causing the blockage. The problem with these sorts of products is that they flow over and around partial blockages, so they never really solve the problem entirely. They are quite effective at breaking down matted hair which has got stuck in the sink's pipe—a good tip if you shampoo your pet in your sink.
Cleaning the U-Bend
Your sink does not connect directly to the main drainage outlet because you'd be able to smell any odours from blocked drains coming up through the plughole if you did. Underneath your sink will be a U-bend which traps some water to act like a valve that prevents this. If you have a plumber carefully unscrew the U-bend from the rest of the wastewater pipe, then it can be cleaned properly. Since fat tends to congeal and get stuck in a U-bend, this is a highly effective means of unclogging a blocked sink. It also helps to prevent problems with your drains further down the system.
Use a Sink Plunger
The action of a plunger creates a vacuum which forces any material that is blocking the pipe beneath it back and forth. You create a tight seal over the plughole with your plunger and squeeze up and down. In turn, this should shift the blockage a little. If you keep up the action on your sink plunger for long enough, then this can result in complete clearance of the problem. You tend to notice when you have been successful because you can hear the waste pipe begin to drain properly with a gurgling sound.
Call a plumber if you need additional assistance with your blocked drains.