The Drinking Water Directive (DWD) and Pre-products
What you need to know about voluntary pre-product certification
The implementation of the European Union’s (EU) recast Drinking Water Directive (DWD) on 1 January 2027 marks important changes for manufacturers in the drinking water sector. Any new products you place on the EU market as a manufacturer will have to comply with new requirements. And while the Directive does not explicitly address pre-products, they are in many cases the best place to start. In this article, we explain why, while also discussing how your company can prepare for the changes ahead.
Where do pre-products fit into the Drinking Water Directive?
The Drinking Water Directive introduces harmonized hygiene requirements for materials and products that come into contact with drinking water across the European Union. “By introducing a single European framework, the new DWD replaces the different national approval schemes manufacturers had to navigate before, depending on where they wanted to sell their products,” explains Kiwa’s Dietmar Altemeier, Business Development Manager, Business Sector Water Germany.
The DWD applies to all finished materials and products that come into contact with drinking water, such as taps, fittings, hoses and cartridges. It does not directly cover the materials used to manufacture those products. These upstream materials are often supplied by manufacturers to be further processed into components or finished products that ultimately come into contact with drinking water. One category of these upstream materials is pre-products, such as plastics, coatings, metals or other materials used in the production process. "More and more manufacturers are discovering that certifying these pre-products can reduce testing, shorten certification timelines, and simplify compliance across the supply chain," says Dietmar.
How to prepare for the DWD
For a broader introduction to the DWD, read our whitepaper "How to prepare for the DWD".
What are pre-products?
A pre‑product is a material with a defined formulation that is supplied in a ready‑to‑use form before it is transformed into a finished product. Common examples include polymer pellets, granules and additives used during manufacturing.
As Dietmar explains, “A granule is called a pre-product because you can't go to a store and buy some granules to fix a tap. You need to engineer a physical transformation or chemical reaction to make the final material.”
Although these materials are outside the legal scope of the DWD, manufacturers can obtain voluntary certification for them. This voluntary certification is based on the same testing principles used for finished products. It can make compliance further down the supply chain a lot easier.
Why voluntary certification?
If pre-products fall outside the scope of the DWD, why invest in certification? Dietmar’s rationale is clear: “It saves time and money.”
He continues, “Imagine three manufacturers all using the same polymer granules to produce different drinking water products. Without pre‑product certification, each manufacturer must assess and test that material as part of its own certification process. The same material can end up being tested repeatedly by different companies. With the voluntary certification of pre-products, that work only needs to be done once. The pre-product certificate can be used by everyone. The company that has obtained certification can simply say to others in the supply chain, ‘I'm using that material, here is the certificate. Done.’ Manufacturers using certified materials can rely on the existing assessment when demonstrating compliance for their own products.”
Depending on the product’s risk group, this approach can significantly reduce the amount of testing required, Dietmar explains. Beyond that, voluntarily certifying a pre-product creates a commercial advantage for its producer: a certified pre-product becomes more attractive, because it helps customers achieve compliance more efficiently.
How does pre-product certification reduce testing?
The time and cost savings of the voluntary certification of pre-products for the manufacturers buying those products depends on the product's risk group.
Under the DWD, products are assigned to different risk groups. A product’s risk level is based on various factors, such as how much of the product comes into contact with drinking water. Higher-risk products require more extensive testing than lower-risk products.
If you are using a certified pre-product in a lower risk group, you're done. You do not have to do anything. You can use that certificate obtained by your granule manufacturer, and manufacture your products immediately, without further testing.
Higher-risk products do require further assessment. However, there, much of the groundwork has already been completed. This is because product certification already covers important aspects, such as formulation review, substance assessment, screening for unexpected substances, and enhanced microbial growth testing. Only a smaller number of additional requirements remain.
The potential savings can be significant, Dietmar emphasizes. Where a certified pre-product is already available, manufacturers can save up to 60% on certification costs. Because the same material is often used across multiple products, these savings can quickly add up across an entire portfolio.
How does pre-product certification impact formulation reviews?
Voluntary pre-product certification also affects the formulation reviews manufacturers face under the DWD. These reviews are one of the most time-consuming stages of DWD certification.
They take place before any laboratory testing begins. This is because certification bodies must first understand exactly what every material contains. To this end, materials must be broken down into their individual substances, and each of those substances has to be checked against the European Positive List.
If a pre-product is made of materials from a range of different suppliers, the formulation review can be a lengthy process. “To begin with, every supplier we contact needs a Non-Disclosure Agreement, or NDA,” Dietmar says, “because the formulation information we’re asking for is confidential. That takes time. It can take one month or it can take two years, depending on the supply chain.”
By contrast, the process can become more efficient if the pre-product supplier has already completed that formulation review. And every customer using the material benefits. “Instead of repeating months of supplier discussions and endlessly resharing and reviewing documentation, they can build on an existing, approved formulation.”
How does pre-product certification work?
Voluntary pre-product certification follows the same technical principles used for DWD certification of finished products.
The process begins with an application and a bill of materials. The certifier, Kiwa, then reviews the product, determines the relevant risk group, and carries out a formulation review before testing begins. Depending on the product and risk category, this process also includes production site inspection, and a final evaluation before certification is issued. The duration of this process can vary a lot, and is influenced by factors such as the complexity of the formulation, and how readily supplier information can be obtained.
As Kiwa is accredited for both pre-product and intermediate product certification, as well as the full scope of the DWD, we can support manufacturers at every stage of the supply chain.
How can manufacturers prepare for 2027 and beyond?
The advantages of voluntary pre-product certification are becoming more widely recognized across the industry. “More and more raw material manufacturers understand that this can deliver real added value for the complete supply chain. They are applying for certification of their granules, as well as for listing in the Fit for Drinking Water database, a searchable register of certified materials that manufacturers can consult when selecting upstream suppliers.”
Dietmar's advice to manufacturers is straightforward: begin with your materials, not your finished products. “First, look at all the materials you are using across your products. Don't look at a single product. Look first at your materials. Then make a risk-based assessment, and choose how to start with DWD certification.”
He also recommends engaging with an accredited certification body as early as possible. “If you make a mistake and test a material in the wrong risk group, you have to do it all over again. Talk to an accredited certification body at the beginning of the process to save time and money further on."
Voluntary, pre-product certification is a practical, highly effective way to reduce duplicated testing, shorten certification timelines and simplify compliance across the supply chain. Whether you manufacture pre-products or finished products, understanding your materials now can make the transition to DWD compliance as of January 2027 considerably smoother.
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