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HR Wallingford has produced a document setting out the general principles that should be considered when repairing or rehabilitating sewers. This work supports the European Standard on Drain and sewer systems outside buildings – Part 5: Rehabilitation (EN752-5) and has involved specialists from 10 organisations across 5 European countries. At present there is a range of national methods for measuring the structural, environmental and hydraulic performance of drain and sewerage systems. Individual countries often have their own rehabilitation criteria, but there was a need for generic guidance providing best practice advice that can be used across Europe. This should be flexible and take account of local issues. The new document allows users to select the most appropriate criteria, applicable to their own country. The structure of the new document is closely related to that of EN 752-5. In each case the rehabilitation procedure is split into four phases: - initial planning - diagnostic study - development of solutions and -implementation/monitoring. The new guidelines cover current methods for measuring the structural, hydraulic and environmental performance of sewers. They look at assessing and prioritising the need for rehabilitation and the section on ‘developing solutions’ has been expanded to include a method for finding the most cost- effective solutions for rehabilitating sewers. Standards for testing rehabilitated networks and certifying renovation products are also addressed. In each section of the new guide, users are referred to relevant parts of EN 752-5. It should be stressed that the Guidelines set out a generic approach that can be modified according to national needs. They are not intended to replace existing national procedures, but will be particularly valuable in countries where there is currently no national procedure. They should also help to achieve convergence of rehabilitation practices across Europe in the longer term. A final draft version of the entire guide can be viewed at www.hi.ihe.nl/srguide. CD and paper versions of the document are scheduled for April 2002.