EVS-EN 1717:2025+A1:2026

This document specifies an analysing methodology for protecting potable water in potable water installations within and outside buildings but within premises from the risk of pollution by backflow of non-potable water and gives recommendations on the design, risk analysis, backflow prevention devices and their installation methods (see Figure 1 and Figure 2). This methodology is also intended to be used outside premises for all water systems connected to a potable water distribution system up to and including the point of use (see Figure 3). The product standards for the specific backflow prevention devices or arrangements are intended to be used in conjunction with this document. For the development of new devices or systems, this document is intended to be used as a reference to establish the necessary level of backflow protection.