Drinking water 2020 The Chief Inspector’s report for drinking water in England www.dwi.gov.uk Published by Drinking Water Inspectorate Nobel House 17 Smith Square London SW1P 3JR Tel: 0300 068 6400 Website: www.dwi.gov.uk © Crown Copyright 2021 ISBN 978-1-911087-33-5 Copyright in the typographical arrangement and design rests with the Crown. This publication (excluding the logo) may be reproduced free of charge in any format or medium provided that it is reproduced accurately and not used in a misleading context. The material must be acknowledged as Crown copyright with the title and source of the publication specified. Drinking water 2020 The Chief Inspector’s report for drinking water in England www.dwi.gov.uk Drinking water 2020 The Chief Inspector’s report for drinking water in England Contents Executive Summary 5 Drinking water 2020 11 The Chief Inspector’s report for England 11 Drinking water quality testing 14 Influence of CoViD-19 on Water Industry Performance 17 Regulation 7 and Zonal Sampling 19 Analysis of Sampling Response 19 E. coli analysis 22 Conclusions 28 Compliance with Standards 30 Compliance Risk Index 30 Learning from compliance failures 33 Microbiological parameters 34 Chemical and physical parameters 44 Isles of Scilly Water 60 Events 63 Regulation 31 and Supervision of Contractors 67 Hardham Treatment Works (SRN) 67 Rill Chillerton Service Reservoir (SRN) 68 Testwood UV Blockage (SRN) 69 Taste and Odour (SVT) 71 Misconnection (SES) 72 Do Not Drink Advice (WSX) 73 1 Drinking water 2020 The Chief Inspector’s report for drinking water in England Discolouration Events 76 Ingleby Barwick (NES) 80 Manchester (UUT) 80 Rownhams (SRN) 81 Tees Cross Valve (NES) 81 Media Interest in Sussex and Kent (SEW) 82 Loss of Supply (TMS) 83 Cryptosporidium Detections at Surface Water Treatment Works 84 Littlehempston Cryptosporidium, Devon (SWB) 84 Eccup Cryptosporidium, West Yorkshire (YKS) 86 Ashford Common Cryptosporidium, London (TMS) 87 E. coli Detections at Surface Water Treatment Works 89 Whittle Dene E. coli detection, Tyneside (NES) 89 Frankley E. coli detection, Birmingham (SVT) 92 Burst Main (TMS) 93 Cautions and Prosecutions 95 Acceptability, Consumer Contacts and Discolouration Review 96 Discolouration Review 99 Materials in Contact with Drinking Water 104 Audits 106 Quarter 1 – Enforcement Notices 106 Quarter 2 – Disinfection 107 Quarter 3 – Service Reservoirs 108 Quarter 3 – Supply Zones 108 Quarter 4 – Groundwater works 109 2 Drinking water 2020 The Chief Inspector’s report for drinking water in England Enforcement 111 New Legal Instruments Issued 111 Completion Reports 113 Change Applications 115 Milestones 115 Radioactivity Notices 117 Monitoring Variations 117 Regulation 15 Applications 118 Recommendations 119 Transformation Programmes 124 Severn Trent Water 125 United Utilities 127 Southern Water 130 Thames Water 132 Northumbrian, Essex and Suffolk Water 134 South West and Bournemouth Water 137 National Risk Assessment 138 Risk Assessment Risk Index 139 Industry top hazards 142 Regulators’ Alliance for Progressing Infrastructure Development (Water) – RAPID 144 Annex 1 146 3 Drinking water 2020 The Chief Inspector’s report for drinking water in England 4 Drinking water 2020 The Chief Inspector’s report for drinking water in England Executive Summary Drinking water 2020 is the 31st published by the Drinking Water Inspectorate (DWI). This report covers public water supplies in England. The provision of safe and clean water direct to the taps of 99% of all homes in England remains vital to health and wellbeing. This was none so more the case than in 2020 when on 23 March the Prime Minister asked people to stay at home. This resulted in a steep rise in demand for water to around 30% above base usage by late May in 2020, equivalent to peak levels seen during the hot summer of July 2018. Whilst this was an obvious outcome as people stayed at home and used water more for personal hygiene, less obvious was the effect on the direct customer interfacing operations of companies such as entry into homes for sampling, events resulting from complications due to restrictions and the added combination of hot weather with usage. This report describes instances where all these were impacted together with the strategies to enable the collection, analysis, inspection and delivery by companies and the Inspectorate to demonstrate confidence in the water supply of England. During 2020 water was abstracted, treated, sampled, analysed and delivered to a high standard by staff who had to work through the pandemic without interruption and unseen. All those involved should rightly be commended on this. Faced with government social distancing restrictions impacting the ability to collect drinking water samples in consumers’ homes, companies initiated innovative approaches to maintain sampling. This included but was not limited to contacting thousands of commercial businesses and company staff to be sample points. This was carried out within a regulatory framework outlined within information letters and notices providing guidance upon which companies based their response. During April to August, at the start of the pandemic the majority of zonal samples were collected upstream of customer properties before recovery began from September when the majority of samples were taken at zonal taps as sample points became available. Maintaining confidence in our water supply is through robust regulation. Companies are required to take a standard number of samples. Statistical analysis between the required regulatory number of samples (2019 dataset) and the number actually taken in 2020 for E. coli (as a primary indicator for 5 Drinking water 2020 The Chief Inspector’s report for drinking water in England the absence of faecal contamination) showed no significant difference with 95% certainty. As such, the industry should be commended on their performance in assuring the quality of the water supply at a most challenging time. The Compliance Risk Index is a performance measure designed to illustrate the risk arising from failures to meet drinking water standards for the parameters specified within the regulations throughout the supply system from source to tap. Since the measure relies solely on the contribution of each failure rather than the overall number of samples, any fluctuation in sample numbers and where they are taken does not affect the measure. This conclusion could not similarly be made for Mean Zonal Compliance (MZC) during the pandemic which would rely on the average value from zonal samples. The CRI for England was 2.64 demonstrating continuing improvement since 2016 when it was developed for use alongside MZC as a measure beyond the ability of MZC to drive measurable improvement. From 2020 it is now the primary measure as companies have an individual outcome CRI of 2 as a common performance commitment agreed with the economic regulator, Ofwat. This value was based upon an estimated median that companies should reasonably achieve by 2020. The median in England for 2020 was 1.61 and so over half of companies are now achieving this demonstrating the high quality of water. Considering company performance, there was significant improvement by Cambridge Water, South Staffs Water and Yorkshire Water. But highly noteworthy is the year on year improvement by Severn Trent Water demonstrating strategic commitment to drinking water quality. Whilst the CRI for Southern Water improved in the last year, the company failed to improve sufficiently for their score to fall below the industry CRI of 2.70. There was also a deterioration in the CRI score for Northumbrian Water noteworthy with the highest individual score. In 2020, the Isles of Scilly (ISC) became part of South West and Bournemouth Water’s supply area, bringing the islands within the responsibility of a licensed water undertaker under the Water Industry Act 1991 for the first time. During this initial period of evaluation and mitigation, results from the Isles of Scilly have been excluded when calculating the company CRI score. When considering specific aspects of sample location, such as those taken at commercial premises and companies own sites as a result of the pandemic, there were particular outcomes of note. Taste and Odour and Iron were among the largest contributors to the CRI scores. Taste and odours are commonly due to consumer plumbing, but the alternative sampling strategy during the year resulted in a 17% reduction in the number of compliance breaches. Nonetheless, at Anglian Water there were 11 taste and odour breaches due to black alkathene supply pipes. One of these failures occurred at Anglian Water’s own offices. Companies should set the standard at their own sites. 6 Drinking water 2020 The Chief Inspector’s report for drinking water in England Whilst the number of lead failures reduced, again due to a reduction in sampling at houses, Bristol Water whose policy of sampling from outside taps predominantly at churches meant that whilst they maintained a zonal sampling programme it also resulted in a 500% increase in the lead failure detections during 2020. This serves as a reminder of the prevalence of lead in older buildings not identified during routine monitoring but highlighted by the change in sampling strategy of Bristol Water. In a further example of not setting standards by example, Thames Water discovered a lead communication pipe on one of their own sites. Similar to lead, iron also had reduced numbers of failures in 2020, but with some unexpected results. Wessex Water recorded an iron failure at their own offices. The location of the samples was from an industrial estate and these failures represent some of the first evidenced outcomes from a significant reduction in water usage in industrial areas, as workers were either furloughed or began to work from home in response to CoViD-19. Many samples were collected from service reservoirs due to restrictions whereupon iron sediment was found within the sample lines as well as sediment accumulating on the reservoir floors.