Sewers for Adoption - water

1 Sewers for Adoption A Design and Construction Guide for Developers Eighth edition August 2018. Published by water UK. th 2018 water UK/WRc plc Sewers for Adoption 8 edition Copyright The contents of this document are subject to copyright and all rights are reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted, in any form or by any means electronic, mechanical, photocopying, recording or otherwise, without the prior written consent of the copyright owner. This document has been produced by WRc plc. August 2018 water UK/WRc plc th 2018 water UK/WRc plc Sewers for Adoption 8 edition FOREWORD. This work to produce this new, 8th, edition of Sewers for Adoption was undertaken in order to give guidance, for the first time, on the design and construction of Sustainable Drainage Systems (SuDS) that may be considered for Adoption under Section 104 of the water Industry Act 1991.

2 This edition of ' Sewers for Adoption ' has been produced following significant contributions from a wide range of interested parties. An initial stakeholder workshop was held in January 2017 and the drafting work has been overseen by a stakeholder group with representatives of developers, local authorities, designers and SuDS specialists. We are grateful to all those who have contributed time and effort to the production of this edition and in particular to Professor David Balmforth who has chaired the stakeholder group. Prior to full implementation, which is expected in mid-2019, this version of Sewers for Adoption will exist alongside versions 6 and 7 of the guide. In that period, while some companies may be in a position to enter into agreements for the Adoption of assets under this new guide, most adoptions will be undertaken on the basis of one of the earlier editions.

3 The legislation in Wales and for Welsh water companies differs from those applicable for English companies and consequently, the arrangements for sewer Adoption in England and Wales are now different. For companies wholly or mainly in England, a new regime is being implemented by Ofwat for the Adoption of Sewers and lateral drains from mid-2019. The new regime is set out in the November 2017 Code for Adoption Agreements. It has been implemented using powers conferred by the water Act 2014. When the new regime comes into effect, there will be a single form of technical guidance for sewer Adoption as well as a single form of Adoption agreement. It is anticipated that Sewers for Adoption 8th edition will form the basis of that technical guidance. The new regime will be implemented through collaboration between water and sewerage companies and those offering sewerage assets for Adoption .

4 This current document may therefore be subject to change as part of the implementation process. Until the new regime comes into effect, the guidance in ' Sewers for Adoption ' does not necessarily preclude alternative requirements on the part of individual water and sewerage companies. These variations are expected to reduce substantially once the new regime is in force as any deviation will need to be agreed with the customer. For companies wholly or mainly in Wales, Adoption agreements are regulated through the arrangements introduced in 2012 by Section 42 of the Flood and water Management Act 2010. Under this legislation, where a connection to an existing public sewer is required, an Adoption agreement must be in place prior to any connection being made to the public sewer . The legislation also provides that the standards in the Adoption agreement must be in accordance with those published by the Welsh Minsters.

5 The agreement may only depart from those standards by agreement of all parties. Welsh Ministers have published standards for gravity foul Sewers and lateral drains but not for surface water Sewers and drains or for pumping stations. 2018 water UK/WRc plc th Sewers for Adoption 8 edition i The standards for gravity foul Sewers in Part B of SfA8 are consistent with the standards published for consultation by the Welsh Government. The Welsh Minsters have also announced their intention to implement Schedule 3 of the Flood and water Management Act 2010 for sustainable drainage systems (SuDS) in Wales in 2018. Schedule 3 of the Act requires the Welsh Government to publish standards for sustainable drainage systems (SuDS) to drain surface water from any new developments that fall within the scope of these provisions. SuDS approved by the SuDS Approval Bodies (SAB) in accordance with these provisions will be adopted by them.

6 The SuDS Approval Body is expected to be the local authority. 2018 water UK/WRc plc th Sewers for Adoption 8 edition ii 2018 water UK/WRc plc th Sewers for Adoption 8 edition iii CONTENTS. FOREWORD I. PART A GENERAL 1. A1 INTRODUCTION 1. A2 APPLICATION 1. A3 STRUCTURE OF Sewers FOR Adoption 3. A4 DRAINAGE STRATEGY 3. A5 DESIGN PRINCIPLES 4. A6 DEFINITIONS 5. A7 SPECIFIC water COMPANY VARIATIONS 7. A8 STATUTORY CONSENTS AND OTHER PERMISSIONS 7. A9 DRAINAGE OF STREETS 8. A10 LAND DRAINAGE 8. A11 CONTROL OF POLLUTION 8. A12 EXISTING PUBLIC sewer AND LATERAL DRAINS WITHIN THE SITE 9. PART B DESIGN AND CONSTRUCTION OF NEW FOUL Sewers AND. LATERAL DRAINS 10. B1 INTRODUCTION 10. B2 SCOPE 10. B3 SEPARATE SYSTEMS 10. B4 HYDRAULIC DESIGN 11. B5 LAYOUT PRINCIPLES 11. B6 LAYOUT AND ACCESS 12. B7 RELIABILITY 45. B8 STRUCTURAL DESIGN AND INTEGRITY 46. B9 MATERIALS 46. B10 CONSTRUCTION 47.

7 B11 TESTING 47. B12 pumping STATIONS 47. PART C DESIGN AND CONSTRUCTION OF NEW SURFACE water . DRAINAGE SYSTEMS 50. C1 INTRODUCTION 50. C2 SCOPE 52. C3 GENERAL 52. C4 SEPARATE SYSTEMS 54. 2018 water UK/WRc plc th Sewers for Adoption 8 edition iv C5 LAYOUT PRINCIPLES 54. C6 HYDRAULIC DESIGN 55. C7 DETAILED DESIGN OF COMPONENTS 58. C8 MATERIALS 0. C9 CONSTRUCTION 1. C10 TESTING 1. C11 MAINTENANCE 1. PART D pumping STATIONS 3. D1 SCOPE 3. D2 DEFINITIONS 3. D3 GENERAL 3. D4 PROVISION OF pumping STATIONS 4. D5 RISING MAINS 11. D6 DESIGN OF pumping STATIONS 14. E1 GENERAL 24. E2 MATERIALS 25. E3 EXCAVATION AND BACKFILLING 40. E4 FORMWORK AND concrete 43. E5 CONSTRUCTION OF GRAVITY Sewers AND RISING MAINS 48. E6 CONSTRUCTION OF MANHOLES, CHAMBERS (INCLUDING NON-MAN INSPECTION. CHAMBERS) AND WET WELL 52. E7 CLEANSING AND TESTING 54. PART F MECHANICAL AND ELECTRICAL SPECIFICATION FOR SMALL.

8 pumping STATIONS 58. F1 GENERAL 58. F2 PUMP UNIT SPECIFICATION 58. F3 ELECTRICAL SPECIFICATION 68. F4 VALVE SPECIFICATION 104. APPENDIX I TYPICAL CONTENTS OF THE CDM HEALTH AND SAFETY. FILE 108. APPENDIX II - PUBLICATIONS RELEVANT TO THE DESIGN OF Sewers , MANHOLES, RISING MAINS AND pumping STATIONS 110. APPENDIX III - BRITISH STANDARDS INCLUDING EUROPEAN. STANDARDS AND CODES OF PRACTICE 111. 2018 water UK/WRc plc th Sewers for Adoption 8 edition v APPENDIX IV - water INDUSTRY SPECIFICATIONS/INFORMATION AND. GUIDANCE NOTES (TO WHICH REFERENCE IS MADE IN THIS. GUIDE) 121. APPENDIX V - PARLIAMENTARY ACTS AND REGULATIONS (TO WHICH. REFERENCE IS MADE IN THIS GUIDE) 122. APPENDIX VI - MISCELLANEOUS PUBLICATIONS (TO WHICH REFERENCE. IS MADE IN THIS GUIDE) 123. APPENDIX VII - STANDARD SYMBOLS FOR USE ON THE DRAWINGS 126. 2018 water UK/WRc plc th Sewers for Adoption 8 edition vi PART A GENERAL.

9 App endix A. A1 INTRODUCTION. 1. This Guide is for use by Developers when planning, designing and constructing foul and surface water drainage systems (including pumping stations and rising mains) intended for Adoption under an Agreement made in accordance with Section 104 of the water Industry Act 1991. 2. The principal changes in this edition of Sewers for Adoption are to Part C, which has been extended to give guidance on the design and construction of Sustainable Drainage Systems (SuDS). and the criteria to be met for SuDS components to be considered for Adoption under a Section 104. Agreement. 3. Any reference to an Act of Parliament or other statutory provision shall include reference to any amendment, consolidation, modification, extension, re-enactment or replacement of that Act or provision. 4. At various places in this document guidance is given on some of the legal terms used.

10 This is without prejudice, as the true meaning of these terms can only be established by the courts. A2 APPLICATION. General 1. Section 104 of the water Industry Act 1991 only applies to the Adoption of assets predominantly used for drainage from buildings or paved areas belonging to buildings. water companies do not have a statutory duty to adopt or maintain assets the main purpose of which is to deal with highway drainage (see A9), land drainage runoff, or flows from watercourses or groundwater (see A10). 2. Where the proposal includes significant technical challenges ( a bespoke in-situ reinforced concrete structure or a novel design), specialist technical vetting may be necessary by the water company. In these cases, the designer is advised to consult with the water company at the earliest opportunity. 3. This document covers new Sewers and lateral drains only, and should not be used as a definitive design manual for all sewerage-related construction such as rehabilitation, etc.