12 Jun 2026
A kitchen sink rarely chokes in one moment. It slows down first. The water takes longer to clear after you wash up, then it sits in the basin while you finish the pan, and then one evening it does not go down at all. What you are looking at is almost never a single object stuck in the pipe. It is weeks of cooking, poured away a bit at a time.
Grease and oil are the real problem
Oil goes down the sink as a liquid and does not stay one. It leaves the pan hot and thin, meets a cooler pipe a metre along, and sets on the pipe wall like candle wax. Nothing about that looks dramatic on the day. The trouble is that it happens after every fry, every wok and every tin drained into the sink, and each layer narrows the pipe a little more.
Once there is a greasy film inside the pipe, everything else that goes down sticks to it. The oil does not block the sink on its own. It builds the surface that catches everything that follows.
What food waste adds
- Rice and noodles, which swell once they are through the strainer
- Coffee grounds, which do not dissolve and pack down into a sludge
- Vegetable peel and eggshell, small enough to slip past a strainer
- Flour, batter and the water from a floury bowl, which set into a paste
- Milk, gravy and soup bases, which add more fat to the same film
None of these will choke a clean pipe on their own. All of them stick to a pipe that already has grease in it.
What is actually in the bottle trap
Under most kitchen sinks in Singapore is a bottle trap, the fat cylinder that unscrews at the bottom. It holds a little water on purpose, so that drain smells cannot come back up through the sink. It is also the first wide, slow part of the pipe run, which makes it the place where the heavy things settle out.
Open one that has not been touched in years and you rarely find water. You find a grey, packed layer of fat and food solids. Clearing the trap often gets a slow sink moving again, but it tells you nothing about the pipe beyond it. If the sink slows again within weeks, that pipe is your answer.
Why boiling water and drain chemicals do not fix it
Boiling water melts fat, but only where it reaches and only while it stays hot. In a sink that is already holding water it does not flow anywhere. It sits in the basin, cools on the way down and arrives weak. On a fully blocked sink it usually does nothing at all, and poured into a plastic waste pipe it can do harm.
Supermarket drain cleaner has the same problem. It has to reach the blockage to work on it, and in a standing sink it dilutes in the water already sitting there. What you are left with is caustic water in your basin, which makes the job more dangerous for whoever opens the trap next and is hard on older pipework and seals. If you have already poured some in, say so when you call.
What to stop pouring away
- Cooking oil and pan fat. Let it cool, pour it into a container and bin it.
- The rinse water from an oily wok or pan. Wipe the pan out with kitchen towel first.
- Coffee grounds and tea leaves.
- Rice, noodles and anything starchy left in the pot. Scrape it out first.
- Flour, batter and cornflour water.
- Soup, gravy and curry, which are mostly fat once they cool.
Then fit a basket strainer over the sink outlet if there is not one already, and empty it into the bin rather than back into the basin. That is most of the job done, and it costs nothing.
When it is not the sink
If the sink slows at the same time as other outlets in the flat, the blockage is further along than the sink waste and it is a different problem with a different fix. Why a floor trap keeps choking covers that side of it.
When to call a plumber
Call when the sink has stopped draining and clearing the trap has not brought it back, when it chokes again within weeks of being cleared, or when more than one outlet is slow at the same time. Any of those means the blockage sits in the pipe run rather than in the trap, and it has to be cleared from the pipe rather than from the basin.
We clear kitchen chokes islandwide and we answer around the clock, our plumbers are qualified and insured, and we supply the hardware if a trap or a waste kit needs replacing. Our drain choke clearing page explains how we approach the job, our pricing page sets out how we charge, and our FAQ page answers most of what people ask before booking.
Keep the grease and the food waste out and the pipe stays clear for years. Once the inside of it is coated, no amount of hot water will undo that, and it is time to call somebody.