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Which plastics are approved for drinking water? Everything about approvals, test procedures and applications of PE, PP, PVC-U & Co.
The use of plastics in contact with drinking water is indispensable in modern supply networks. They are used in pipes, seals, fittings, tanks and in a wide variety of domestic technical devices. Their advantage lies in their high resistance, ease of processing and cost savings compared with metallic materials. At the same time, strict requirements apply to ensure that the materials do not impair water quality and do not give rise to any health risks.
The subject is complex because different national and international requirements interlock and a large number of testing institutions are involved. For manufacturers this means a high organisational and technical effort, but at the same time also a great responsibility: the quality of drinking water must not be jeopardised by any component of the piping system.
This article examines the legal foundations, approval procedures, test methods, areas of application as well as health-related and future-oriented aspects in a comprehensive manner and shows why plastics play a central role despite all the challenges.
Requirements and legal framework
In Europe, drinking water is regarded as the most closely monitored foodstuff. This means that the requirements for all materials that come into contact with it are particularly high. In Germany, the Drinking Water Ordinance (TrinkwV) governs the basic requirements. In addition, the UBA guideline paper on plastics in contact with drinking water provides the practical basis for manufacturers and testing institutes.
These guidelines contain positive lists for approved monomers, additives and auxiliary substances. At European level, work is under way with the EU Drinking Water Directive (Directive (EU) 2020/2184) on a harmonised standard that is intended to reduce national differences in future. This harmonisation is of central importance, since manufacturers offer their products throughout Europe and a uniform legal framework creates planning certainty.
In addition to European and German requirements, there are also industry-specific standards and recommendations. These include, for example, DIN EN 16421 for testing sensory properties or DVGW worksheets, which define specific requirements for piping systems. International organisations such as the WHO also issue recommendations on materials in the drinking water sector.
Approvals for plastics in the drinking water sector
An approval is mandatory before plastics may be used in drinking water applications. In Germany, responsibility lies with the Federal Environment Agency (UBA), which publishes positive lists for approved materials. Manufacturers must submit detailed test reports demonstrating migration, sensory properties and hygienic suitability.
In addition, industry-specific certifications such as DVGW approval for piping systems or fittings play an important role. These certificates give planners and installers the assurance that the products used meet the high requirements. At international level, further standards are added, such as NSF/ANSI 61 in the USA or WRAS approval in the United Kingdom. For globally operating manufacturers, this means that they often have to have their products tested in parallel according to different standards.
Some countries also have their own national lists or approval procedures. It is therefore important for exporters to develop an international approval strategy at an early stage.
Test methods for assessing suitability
The suitability of a plastic for contact with drinking water is demonstrated in extensive test series. These include:
- Migration tests: These check whether constituents pass from the material into the water. The tests are carried out with defined test media and over specific periods in order to simulate long-term effects as well.
- Sensory tests: Here it is checked whether the water is impaired by the plastic in terms of taste, odour or appearance. Even minimal changes can lead to exclusion.
- Mechanical tests: These examine the resistance of the material to pressure, temperature changes and mechanical stress. Particularly in hot water systems, plastics must demonstrate high stability.
- Hygienic suitability: These tests check whether the material surfaces promote the proliferation of microorganisms. Microbiological neutrality is a basic prerequisite.
In addition, ageing and long-term tests are often carried out to ensure that the materials remain stable over many years. Simulations and accelerated ageing tests can also provide information on how plastics behave over decades in practical operation.
Typical areas of application
The range of applications for plastics in the drinking water sector is wide:
- Pipes: Polyethylene (PE-HD), polypropylene (PP) and polyvinyl chloride (PVC-U) are standard materials in cold and hot water supply. They impress with their freedom from corrosion and long service life.
- Seals and fittings: Elastomers such as EPDM or PTFE as well as plastics such as POM are used in valves, taps and couplings. They guarantee tightness and functional reliability.
- Storage and container systems: Plastic tanks for hot water or intermediate storage are light, hygienic and chemically resistant.
- Domestic technical equipment and devices: Coffee machines, water filters, drinking water carbonators and similar devices also rely on tested plastics to ensure hygiene and safety.
The same principles also apply in the food and beverage industry when plastics come into contact with water or water-based products. In addition, plastics play a growing role in decentralised treatment systems, such as small filter systems in private households or modular systems in emergency supply.
Health aspects and risk assessment
A central point in the use of plastics in the drinking water sector is the health risk assessment. Additives, plasticisers or stabilisers must not enter the water in health-relevant quantities. Furthermore, materials must be designed in such a way that they do not provide a breeding ground for germs. This is a critical factor, particularly in stagnating pipe sections.
Studies show that with properly tested plastics the risk of releasing harmful substances is minimal. Nevertheless, approval procedures are continuously being developed further in order to detect even the smallest quantities of potentially problematic substances.
Future and developments
Future development will be strongly shaped by the European harmonisation process. The planned Europe-wide positive list is intended to simplify the testing and approval process and reduce the effort required by manufacturers. At the same time, the pressure to use sustainable materials is increasing. Recycled plastics are a particular focus here, but they come up against tight limits in the drinking water sector, since absolute purity is decisive. Research projects are concerned with the development of new, environmentally friendly additives as well as with bio-based plastics that nevertheless meet the high requirements for migration and hygiene.
Another trend is the digitalisation of approval processes. Databases are intended to enable faster access to approved materials in future, so that manufacturers and planners can easily trace which plastics may be used in which areas of application.
In addition, research is being carried out into innovative functionalities: antimicrobial surfaces that inhibit bacterial growth, or self-healing plastics that can close cracks on their own, could play a role in future.
In conclusion
Plastics are indispensable for a safe drinking water supply and have established themselves as versatile and long-lasting materials. In order for them to be used, they must undergo a complex approval procedure and meet the highest requirements. Only through the combination of migration tests, sensory tests, mechanical load-bearing capacity and hygienic suitability is it ensured that drinking water quality and consumer protection remain secured at the highest level.
At the same time, the materials are caught between growing demand, increasing sustainability requirements and internationally inconsistent approval standards. Manufacturers, planners and operators are therefore called upon to continuously engage with new developments and to adapt their own systems to the requirements applicable in each case.
The future will bring further harmonisation, new material developments and possibly also more sustainable solutions that meet the high hygiene standards while at the same time satisfying ecological requirements. Those who rely on innovations at an early stage gain long-term advantages in a sensitive and safety-relevant market.
FAQ
Which plastics are approved for drinking water? Typical plastics are PE, PP, PVC-U, POM and certain elastomers such as EPDM. However, the decisive factor is official listing in the positive lists of the UBA or other international bodies.
How long does the approval of a plastic take? Depending on the material and the intended area of application, approval can take several months to over a year. Extensive tests and expert reports are mandatory.
What role does the Federal Environment Agency (UBA) play? The UBA assesses the hygienic suitability of plastics, draws up positive lists and is therefore the central authority for approvals in Germany.
Are there international differences in approvals? Yes. While the EU Drinking Water Directive is decisive in Europe, NSF/ANSI standards apply in the USA and WRAS requirements in the United Kingdom. Harmonisation is under way.
Which developments are shaping the future? In addition to European harmonisation, sustainable plastics, digital approval systems, innovative surfaces and new test methods are important drivers for the coming years.
