My tap water smells. Should I worry?


Everyone enjoys quenching thirst with a glass of water. However, many people have experienced salty or metallic water taste or chlorine, mouldy, earthy, or fishy water odour.

Valuing a glass of tap water on the World Water day in 2021, is this year’s theme to raise awareness of this essential resource. Is it simple to produce tasteless and odorless tap water? Pure water is tasteless and odorless, however, on the way from the source to the tap, chemical compounds can enter into water that can change its aesthetic appearance. Drinking water quality is a dynamic concept. It includes standards and presence of chemical and microbiological parameters.

Taste and Odour (T&O) are the two drinking water quality parameters that exist since the dawn of human civilisation. Currently a large number of substances have been identified as causing aesthetic problems to water and the climate change effects seem to amplify the odour problems of water resources.

The presence of T&O in water is usually an early alarm for some problems not necessarily of health significance. However, the World Health Organisation alerts that any unusual aesthetic appearance of water makes consumers worried and prone to use aesthetically more acceptable, but potentially less-safe water. About 100 countries have included T&O in their drinking water standards.

Can we combat the problems of T&O in tap water?

To answer this challenge, the WaterTOP COST Action has set the first European network connecting multi-disciplinary experts and international institutions from 37 countries working in the field of sensory and chemical analyses, water treatment and risk assessment. T&O seems to be a complex effect of a palette of natural and anthropogenic factors – water resources pollution, algae presence, inappropriate water treatment or unsuitable distribution pipes’ material can be just some of the reasons, others are subjects to advanced investigation.

Appropriate detection of T&O and reducing the subjective influence of human sensors is another challenge for which WaterTOP is looking for know-how transfer from the food analyses. Applications of emerging advanced oxidation processes, the identification of bio activity and toxicity of T&O compounds and their transformation products, the determination of T&O markers for early detection of water quality problems are other subjects for ideas exchange, brainstorming discussions, and knowledge dissemination within the WaterTOP framework.

The Action members are dedicated to make WaterTOP have a strong impact in improving protection of public health and water resources, quality of life, use of tap water, consumer’s awareness and involvement in water quality issues and professional development of young researchers in the field.

A number of useful tools will be prepared, such as a novel, open access database and a unique e-tool for T&O compounds for assisting the detection, interpretation, and evaluation of the laboratory results. The WaterTOP members work on suggesting preventive/corrective measures for T&O problems in the Water Safety Plans and development of EU standards for relative methods of T&O testing and for materials in contact with water.

No doubt, the implementation of these activities will contribute to improving people’s confidence in tap water, thus promoting the reduction of plastic bottles utilization, in line with the EU Green Deal targets.

View the Action Website

View the Network website

UN World Water Day website

Photo – courtesy of Dimitar Aleksov for WaterTOP