Chemical engineer's trick to prevent bad smells from drains: 'The most effective method...'

No one wants unpleasant odours to build up in their home, so identifying where they come from is the first step in preventing them. In most cases, the problem originates from the drain trap. This is a curved pipe in which water is retained, preventing gases from the plumbing from escaping. These traps are usually installed in sinks, washbasins and similar fixtures.

However, although the main task of siphons is to act as a water seal and prevent bad smells, according to chemical engineer Diego Fernández (@renovandoconideas on social media), when you have a drain at home that you hardly ever use "that water seal can be lost through evaporation, causing bad smells to seep in".

To prevent this from happening, we can resort to a very simple homemade trick. All you need to do is pour a little water to fill it up again and prevent the passage of gases from the pipe.

Things get a little more complicated in those cases where the siphon accumulates organic matter, which, as Fernández says, "creates a biofilm of bacteria that generates bad odours". In this case, a more thorough cleaning is necessary.

The first thing the expert highlights is that the fix that many people resort to - baking soda and vinegar - does not work, as this mixture "only creates bubbles". The most effective method is to use sodium percarbonate, adding one or two tablespoons to the drain and pouring in a litre of hot water.

In this way, "we chemically break down organic matter and biofilm. In addition, the percarbonate alkalises and helps to emulsify the grease". For best results, leave this mixture for about 20 minutes and then rinse it off using another litre or two of warm water.

In the event that the smell persists, it is most likely due to a problem with the siphon itself, in which case an anti-odour valve can be installed to prevent the return of gases.