When the Drinking Water Inspectorate (DWI) is processing applications for approval of products or treatment chemicals for use in contact with drinking water under the requirements of Regulation 31 of the Water Supply (Water Quality) Regulations 2016 the main causes of delays relate to inadequate Instructions for Use and failures to provide full formulation details of the product and it’s components ingredients, or to provide adequate MSDSs. This FAQ covers product formulation and the associated MSDSs – see also section 3.7 of Advice Sheet 1 “Overview of the Application Process”.
Why are full formulation details required?
Approval of products for use with water intended for human consumption under the relevant regulations, is based upon consideration of the constituent chemicals within the product, how the product will be used, and usually, on the results obtained in a range of laboratory tests. Final approvals granted are given on the basis that there will be no undeclared changes in product ingredients, methods of manufacture etc. Procedures for changes in products or their manufacture are covered in Advice Sheet 4 “Changes to Approved Products”.
Most countries that have established regulatory requirements for the approval of products for use in contact with drinking water include a review of the full formulation of the product (often including reference to a “positive list” of acceptable ingredients) taking into account possible ingredients that might pose a risk to human health. Although we do not currently use a positive list of acceptable ingredients for thermoplastic materials we cannot process applications for approval of products containing non-metallic materials without a FULL declaration of the formulations of these materials.
What formulation details are required?
We need the following information, as a minimum –
- the full chemical name of each ingredient
- the CAS number of each ingredient
- the percentage concentration of each ingredient (adding up to total of 100%)
Note: there is no standard format for this information, provided that it covers the points listed above.
Normally this information would be supplied in the appropriate Application Form available from our website. We are unable to progress the approval process for any product if this information is not supplied either by the applicant, or in many cases, by one or more of his suppliers when this includes “company confidential” information.
In a similar way we will need a full declaration of the formulation details for each of the ingredients used in the final product – often this information will not be available to the applicant for approval, but will have to be supplied directly to the DWI, in confidence, by the ingredient supplier(s). Again the same level of information is required as set out earlier.
Why do we need the material safety data sheets (MSDS)?
These sheets will be available for each ingredient, and often for the final product being considered for approval. They provide us with essential information on all ingredients present in products, and in their components, together with notification of potential compounds of concern to human health.
MSDS of the product
MSDS are issued for many approved products to provide relevant information to the end user, e.g. polymeric coatings. In cases where MSDS are issued for a product being considered for approval, they are assumed to be controlled documents and are treated with equal importance to the Instruction for Use document(s). This MSDS, that accompanies the product to the site of use or installation, does NOT need to contain a full declaration of the product formulation, provided that this information has been provided in another format to us.
If an approval holder updates the MSDS for their product, it is their responsibility to ensure that we have a copy of this up-dated MSDS on file 
MSDS for product ingredients
MSDSs for each ingredient of your product will be considered during the approval application process. If these MSDSs do not list ALL component chemicals used in the ingredient, we will have to receive these directly from the appropriate supplier(s). The basic information required is set in “3a to c” on the previous page. If the MSDS refers to “confidential” or “proprietary” chemicals/ingredients we cannot accept it; we will have to receive a full declaration of these ingredients from the relevant supplier(s).
Approval of each material or component in the final approved product is given on the basis of the particular grade of the ingredient and the particular supplier of it – normally generic approval of a particular ingredient is not given. If you need to change the supplier of one of your ingredients, then you will need to follow the procedure set out in Section 2 of our Advice Sheet 4 .
Provided you do not change your supplier we would not expect to be provided with updated MSDS for the individual ingredients UNLESS changes have been made to them by your supplier.
Often some or most of the information required will be commercially confidential – please see our FAQ 3 for further information. If you or your suppliers are unable to provide such information, in confidence, then we will be unable to progress your application or request any further.
 We can also accept formulations based entirely upon 100 parts of the base polymer used (i.e. parts per hundred polymer ), provided ALL ingredients and their concentrations are declared, but not mixed units
 We have a similar requirement for revisions/updates to the Instructions for Use documents (IFU) of approval products, but unlike changes to the IFU, we do not normally issue new approval letters for revised MSDS unless they are an integral part of the IFU.