In this paper a methodology for the quantitative evaluation of the magnetic performance of the anti-scale magnetic treatment devices is proposed and two model devices with rare-earth permanent magnets wrapped around a pipe are analyzed and proposed for potential application at high water-flow capacity (few hundreds of m(3)/h). These devices are very easy and fast to design and to install and have the merits of no operation costs, therefore, despite the high primary investment needed at the present time compared to normal electromagnet based devices, long term they could be less expensive than these. (C) 2013 Elsevier B.V. All rights reserved.