Types:
This Evaluation Guideline includes the following types:

  • Family E, type A, controllable check valve with verification connection
  • Family E, type B, non-controllable check valve, including check valve cartridge
  • Family E, type C, controllable double check valve with verification connection
  • Family E, type D, non-controllable double check valve, including check valve cartridge


Scope of application:
The types of check valves mentioned in point 1.2.1 are meant as backflow protection device.
Check valves with a nominal diameter smaller than or equal to 50 mm are meant for application in domestic water supply systems with a maximum constant water temperature of 65°C and with a maximum water temperature of 90°C for up to maximum one hour. Check valves with a nominal diameter of more than 50 mm are only meant for water temperatures up to 65°C. Check valves are meant for application in domestic water supply systems with a work pressure of up to 100kPa.

The Kiwa Water Mark is needed when you, as a producer or supplier, want to profile yourself on the market with products that meet all requirements: all functional requirements as well as all legal hygienic requirements specified in the “Materials and chemicals in the supply of drinking water and warm tap water Regulation” of the Dutch government.

Steps to obtain a certificate with the Kiwa Water Mark are:

  1. Fill in an application form and send it to Kiwa (application form is located on the right side);
  2. Kiwa sends a quotation, which is at the same time a concept-agreement, drawn up according to the requirements of the guideline;
  3. After mutual signing of the quotation, the agreement is definitive and the initial audit can start;
  4. After positive results of the initial audit, the certificate will be issued;
  5. The certificate is valid indefinitely;
  6. A part of the agreement is periodic audits.

Important aspects of the initial audit (steps 3 and 4) include:

a) Testing with regard to the product and/or performance requirements. Testing, often carried out in our own laboratories, demonstrates that the product meets the certification requirements for functional and hygienic aspects, such as durability, dimensions, composition of materials, etc.;

b) Assessment of the production process, quality system and internal quality control (IQC) scheme. To ascertain that the producer is continually able to manufacture products that meet the certification requirements.

The periodic audits aim at the maintenance of the management system, in order to maintain confidence that the producer is still able to manufacture products that meet the certification requirements. The periodic audits include functional and hygienic tests of the certified products.

The audit frequency varies from product group to product group: in general, 2 to 4 times per year.

Conditions for the certification process are stated in the Kiwa Regulations for Certification and the General Terms and Conditions of Kiwa for the performance of orders.