Blockages almost always form from deposits that build up in the pipe over time. In the bathroom it is usually hair, soap residue and lime; in the kitchen, fat and food scraps that solidify in the pipe; and in the toilet, insoluble items such as wet wipes or hygiene products that do not belong in the sewer. Outdoors, roots can grow into leaking pipes. At first the water drains only sluggishly, until the pipe is finally fully blocked.
Simple blockages in the trap can often be cleared with a plunger or by cleaning the odour trap. Chemical drain cleaners should be treated with caution: they attack seals and pipes and barely help with solid plugs. If the blockage sits deeper, the specialist arrives with professional tools – from the electric drain auger that mechanically breaks up the plug to high-pressure jetting that flushes the pipe clear with water pressure.
For recurring or stubborn blockages, the plumber carries out a drain-camera inspection. It shows exactly where the cause lies – e.g. a pipe offset, ingrown roots or a fat layer – and whether a permanent repair is needed. This avoids working blind and instead targets the cause.
A simple blockage at an easily accessible drain is often cleared in under an hour. As a guide, a simple mechanical drain cleaning costs around CHF 150 to 350, while high-pressure jetting with a camera inspection can cost CHF 300 to 800 and more depending on effort (no guarantee). Emergency call-outs outside business hours carry a surcharge.
What to watch for: don't pour fat or flush wet wipes down the drain, use hair strainers in the shower and basin, and occasionally flush drains with hot water. Tackling a beginning blockage early prevents the plug from growing into a full blockage and, in the worst case, backing up wastewater.