Skip to content
Certified to ISO 9001:2015

Technical article

9 July 2026

The New KTW-BWGL Has Been in Force Since 1 July 2026

An overview of the key changes

Black elastomer seal in water, seals for drinking water applications to KTW-BWGL

The new KTW-BWGL (the German Environment Agency’s (UBA) evaluation criteria for plastics and other organic materials in contact with drinking water) came into force on 1 July 2026 and brings changes above all for elastomers (rubber) and TPE.

From this date, the annexes for elastomers and TPE are legally binding.

1) Previously valid on the basis of the old ELL

New since 1 July

New evaluations, divided into

  • Elastomers to KTW-BWGL Annex D
  • TPE to KTW-BWGL Annex E

2) Stricter positive lists for compounds and formulations

A blanket statement such as the previous “EPDM is suitable for drinking water applications” is no longer sufficient in this form.

A more detailed breakdown now applies:

The substances used must be included in the currently approved lists.

3) New, fixed test requirements

Elastomers / compounds

  • Migration of organic substances
  • Classification of odour and taste and how they are affected
  • Formulation review
  • Microbial growth

Component testing

  • Migration testing to DIN EN 12873-1
  • Odour / taste to DIN EN 1420
  • Microbial growth to DIN EN 16421 (formerly DVGW W270)

4) New rules and requirements for seals in drinking water applications

  • New material tests and releases
  • Proof of conformity
  • Complete traceability of the compound

5) Clear designation of materials and compounds

Example: elastomers

  • Previously: “EPDM 70 KTW black”
  • New: “EPDM 70° Shore black according to positive list KTW-BWGL Annex D”

Example: TPE

  • Previously: “TPE-S 70 black KTW”
  • New: “TPE-S Dryflex 70° Shore black according to positive list KTW-BWGL Annex E”

The new KTW-BWGL turns a simple material approval into a stricter, formulation- and product-related drinking water assessment. For elastomer and TPE seals, manufacturers must update their compounds and supporting evidence.

Feel free to ask us: we will advise you on the possible designs.

More knowledge

More articles

Which Materials Are Suitable for Heat-Resistant Flat Seals?

Heat-resistant flat seals are used in a wide range of industries, including chemicals, oil and gas, automotive and heavy industry. They are essential for ensuring the tightness, safety, efficiency and service life of systems operated under extreme thermal loads. But which materials are suitable for such applications? In this article, we look at the properties and possible uses of materials such as graphite, PTFE (polytetrafluoroethylene) and metal-reinforced seals. With this analysis, you can make the best choice of material for your specific requirements.

Read more

Differences Between Graphite and EPDM Flat Seals

Flat seals play a central role in sealing technology, as they are used in a wide variety of industries and installation situations. Two of the most different materials for flat seals are graphite and EPDM (ethylene propylene diene rubber). Both materials have specific properties that predestine them for different applications. In this article, we look at the chemical, mechanical and thermal differences to help you make an informed decision.

Read more

Why EPDM Flat Seals Are Suitable for Sanitary Applications

EPDM (ethylene propylene diene monomer) has established itself as an outstanding material for flat seals in sanitary applications. With its combination of chemical resistance, thermal stability and flexibility, it meets the high requirements of this industry. In this article, we examine the technical properties of EPDM and show why it is predestined for use in sanitary installations.

Read more

Cooperation

Questions about your seal?

Are you planning a specific application? Talk to us, we will advise you on material, standard and the right manufacturing process.

Get in touch To the flat seals