Medicines, paint and hydrochloric acid: where they should actually go
The drain feels like the easiest bin in the house. For three categories it is the most expensive route there is.
Whatever disappears down the drain is out of sight — and therefore feels dealt with. That feeling is wrong: the water goes to a treatment plant built for household wastewater, and the pipe leading there is yours until past the property boundary.
Dutch consumer authority Milieu Centraal is explicit about three categories. Old medicines go back to your pharmacy and are not flushed down the toilet. Paint, turpentine, hydrochloric acid and other chemicals do not belong in the sewer. And oil and frying fat do not go down the toilet or the sink, but are handed in separately.
That hydrochloric acid appears on that list deserves attention, because it is also sold as a drain opener. A chemical unblocker poured into a pipe that is already closed simply sits there — on the debris, against the pipe wall, and shortly afterwards in the bucket of whoever unscrews the trap. So say so if you have used something: that is not a confession but safety information for the technician who arrives.
The practical route is short. Medicines to the pharmacy, chemical waste and leftover paint to your municipality's recycling or hazardous-waste point, cooled fat into a bottle or jar for the residual waste. If the drain is still slow after that, something mechanical is going on rather than something chemical: having a blockage cleared costs € 125-350 and a camera inspection € 85-175 when the cause refuses to be guessed. Every rate is in the price index.