Microplastics in drinking water: how water filters provide a solution

Micro- and nanoplastics in drinking water represent a growing challenge – particularly for operators of drinking water systems who are responsible for consistently high water quality.

That’s why in the following article, we’ve taken a closer look at the actual risks posed by microplastics, the pathways through which they enter drinking water – and how modern filtration systems, especially hollow fibre membranes with defined pore sizes, can help reduce these risks.

What is microplastic – and how does it enter drinking water?

Microplastics are plastic particles ranging from 1 micrometre (µm) to 5 millimetres (mm) in size.

These particles are formed, for example, through the breakdown of plastic waste, abrasion from clothing and tyres, or industrial processes.

UK research – including studies by the Drinking Water Inspectorate (DWI) – shows that microplastics can enter soils and groundwater and thus drinking water sources.

How do microplastics enter the human body?

Microplastic particles can enter the human body via inhalation, drinking water or food.

They have been detected in various sources of drinking water, including tap and bottled water. Studies suggest that individuals who consume mostly bottled water may ingest significantly more microplastics than those who drink tap water.

Health risks: an invisible threat?

According to the UK Committee on Toxicity (COT), health risks from microplastics are currently considered unlikely – however, robust toxicological data, particularly for smaller particles, is still lacking.

Microplastics as carriers of pollutants

Microplastics may pose a risk not only due to their physical presence, but also because of their ability to adsorb and transport environmental pollutants.

Microplastic particles with a large surface area and hydrophilic properties can, according to a German study, accumulate various environmental toxins on their surface – such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), and flame retardants. These pollutants can adhere to microplastics in the environment and thus enter the food chain.

This means that microplastics may not only be potentially harmful themselves, but can also serve as carriers for other harmful substances.

Why act now – even in the absence of proven health risks?

Although direct evidence of health damage is still lacking, several arguments support the early implementation of protective filtration measures.

Especially for operators of drinking water systems, responsible precaution is better than passive waiting.

Precautionary principle: taking responsibility before it's too late

The European precautionary principle encourages preventative action when potential harm cannot be ruled out – even if full scientific certainty is lacking.

Since micro- and nanoplastics have already been found in human stool, blood and placenta, and potential cellular effects are being investigated, using certified point-of-use filters is a simple and effective risk reduction measure.

Research gaps – and growing concerns

Institutions like the UK Committee on Toxicity (COT) and the World Health Organization (WHO) agree: long-term toxicological data is lacking, particularly for nanoplastics.

At the same time, there is growing evidence of potentially negative effects on the immune system, the gut, and cellular metabolism. While the WHO currently does not identify an acute health risk, it does recommend keeping microplastic levels in drinking water as low as possible as a precautionary measure.

Protecting Sensitive Groups and Hygiene-Critical Areas

In high-risk environments like hospitals, dialysis centres, care homes or nurseries, avoidable risks should be eliminated wherever possible.

Decentralised filters with validated retention capacity (e.g. ≥ 7 log levels at 0.2 µm) effectively prevent microplastics from reaching vulnerable individuals.

Safeguarding reputation and building trust

The topic of microplastics has long since entered public discussion. Operators who invest early in transparent, verifiable filtration solutions not only strengthen user trust, but also position themselves as responsible institutions.

Environmental burden is increasing – filters send a clear message

With rising plastic consumption, water cycle contamination is increasing. Municipal treatment alone is insufficient for microplastic removal.

Hollow fibre membrane filtration – proven in clinical settings – provides a robust supplement to ensure water quality in sensitive environments.

Can water filters remove microplastics?

The extent to which microplastics are removed depends on the filtration technology.

Mechanical membrane filters can effectively retain particles larger than the pore size – high-quality filters can achieve reductions of several log levels.

Activated carbon filters are primarily designed to bind chemicals and odours – their ability to capture solid particles like microplastics is limited, especially at very small sizes.

Filters with defined pore sizes, such as 0.2 µm hollow fibre membranes, are particularly effective because they form a reliable barrier against particles of that size and larger.

Thus, properly selected water filters can make a major contribution to reducing microplastics in drinking water – especially when tailored to specific applications.

What about nanoplastics?

Nanoplastics are even smaller than microplastics – typically defined as smaller than 1 µm, often in the 1 to 100 nm range.

This poses a challenge for traditional mechanical filters, as these particles can pass through standard membranes. However, research is actively developing ways to address this.

However, research is actively working on solutions for removing nanoplastics from water. Studies – for example, this one from 2021 and this one from 2024 – conducted under laboratory conditions show that this is possible through targeted processes such as:

• Agglomeration (binding particles with additives such as magnetic agents)
• Adsorption using high-surface-area filter materials (e.g. charged activated carbon)
• Functionalised membranes that exploit interactions with nanoplastics

Processes such as reverse osmosis do remove large portions of nanoplastics from water, but this comes at the expense of drinking water quality, as essential minerals and salts are also filtered out. In addition, the process is relatively expensive and has a high water consumption.

Why is the topic of microplastics especially relevant for operators?

Hollow fibre membrane water filters not only protect against germs, bacteria, Legionella and Pseudomonas – they also help reduce emerging risks such as microplastics.

Their use is in line with hygiene regulations, particularly in sensitive sectors like healthcare, laboratories, dialysis centres or the pharmaceutical industry.

Conclusion: effectively removing microplastics from drinking water

While municipal systems may not always suffice, 0.2 µm hollow fibre membrane filters can retain particles ≥ 0.2 µm – including most microplastics.

Such filters make a valuable contribution to drinking water safety – especially in areas where hygiene is not optional, but essential.

Do you operate a drinking water system?

Then Aqua free hollow fibre membrane filters are a wise investment – a clear measure against microplastics in drinking water and a safeguard for your users.