(FAQ11) Use of metallic products with brackish water intended for treatment for human consumption.

Introduction

In desalination plants metallic components will be in contact with brackish water before the water is treated for human consumption.

Metallic products and brackish water

The Drinking Water Inspectorate (DWI) does not have any direct concerns over the use of metallic products with brackish water. DWI assumes that water suppliers who intend to use metallic components with brackish water will have taken the necessary steps to ensure that they are satisfied about the compatibility/fitness for purpose of the chosen metal for use with the worst-case water type envisaged.

Where the chosen metal is in contact with brackish water which will be treated for drinking water purposes, it is the user’s responsibility, together with the plant supplier/designer to ensure that any chemical reaction between the metal and the brackish water will not contribute to deterioration in the final quality of treated water.

Compatibility of approved grades of stainless steel

Currently certain grades of stainless steel have been assessed and recognised for use with water intended for human consumption (see Stainless steel grades in Annex 3 of the approved products list). These recognised grades are used in several approved products listed in the List of Approved Products .

If you intend to use one of these grades in contact with brackish water it is important that you establish that the chosen grade is compatible with brackish water.