26 YORKSHIRE WATER SERVICES LIMITED
Introduction
Yorkshire Water Services Limited supplies on average about 1,257 Ml/d water to about 4.71 million consumers in Yorkshire. 78% of the Company’s water supplies come from river and reservoirs. The remaining 22% comes from boreholes. The Company has 121 treatment works, and distributes water through 30,000 km of pipes and 432 service reservoirs to 214 water supply zones.
Overall water quality
At water treatment works and service reservoirs and in water supply zones, the Company carried out a total of 273,309 determinations in 2000. Of these, 99.9% demonstrated compliance with the relevant PCV, but 306 showed a contravention to have occurred.
Coliforms were not detected at 116 (96%) of the Company's 121water treatment works. At all of the Company's 432 service reservoirs, coliforms were absent from at least 95% of samples. Of the Company's 214 water supply zones in 2000, 203 (95%) complied fully with the relevant water quality standards or had breaches of the standards which were either trivial or were fully covered by undertakings. In the other 11 (5%) of the zones, some breaches are regarded as unlikely to recur, but others could result in enforcement action.
Microbiological quality of water leaving treatment works
The Company complied with the sampling frequencies required by regulation 17 at 120 of its 121 treatment works in 2000. The shortfall at the remaining works is regarded as trivial.
Table 26.1 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences over the last three years in the number of treatment works, and samples from treatment works in which coliforms were detected are not considered significant.
All contraventions of the standards at works are considered trivial or unlikely to recur, or covered by undertakings.
Microbiological quality of water in service reservoirs
The Company complied with the sampling frequencies required by regulation 18 at all of its service reservoirs in 2000.
Table 26.2 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. There have been significant decreases over the last three years in the number of service reservoirs, and samples from service reservoirs, in which total coliforms were detected. All other differences are not considered significant.
Contraventions of the microbiological quality standards at one service reservoir has resulted in the consideration of enforcement action, as shown in table 26.4. All other contraventions of the standards at service reservoirs are considered trivial or unlikely to recur as a result of actions taken by the Company, or covered by undertakings.
Water quality in water supply zones
The Company failed to comply with the required sampling frequencies for nitrite in one zone but this was considered trivial.
Table 26.3 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. There have been significant reductions over the last three years in the number of zones failing to comply with the standard for iron, manganese, turbidity, lead and THMs. Other differences in zones are not considered significant.
Enforcement action is being considered in respect of some contraventions of standards, as shown in tables 26.3 and 26.4. All other contraventions of the standards in zones are considered trivial, or are covered by undertakings.
Inspection
Audit trails of five samples
Mr R M Walls, Consultant, working under the direction of Mr W M Waite, Principal Inspector, carried out an inspection of Yorkshire Water Services Ltd during September 2000. Based on his report Mr Waite concluded that:
There are a few improvements that should be made to sample handling and the AQC, but the laboratory has made some changes since the date of the samples. Water quality has been monitored by appropriate techniques and analytical results, with one exception, should be representative of the water supplies from which they were taken. Where breaches have been detected the Company has investigated. The Public Record has been maintained up to date.
Audit of plumbosolvency treatment and control programmes of work
In December 2000, Consultants WS Atkins, represented by Mr M Kimber, working under the direction of Mr P Halton, Inspector, carried out an audit of the Company as part of the Inspectorate’s work in agreeing with water companies’ their programmes of works to secure compliance with new lead standards. Based on Mr Kimber’s report, Mr Halton concluded that:
the Company’s process of sites/scheme selection for plumbosolvency treatment and/or optimisation measures is sound;
the integrity of the data submitted to the Inspectorate and used for assessing plumbosolvency was confirmed;
the schemes audited are justified on water quality reasons; and
the Company is unlikely to install, commission and optimise all of the plumbosolvency programme of works within the required timeframe.
Follow-up of response to recommendations and audit of arrangements for Cryptosporidium sampling
The Inspectorate audited Yorkshire Water Services Limited on three occasions in February, September and November 2000. The Inspectorate concluded that:
The Company has taken satisfactory action in respect of most of the recommendations made during the 1999 inspection;
The Company has generally implemented satisfactory arrangements for Cryptosporidium sampling, but there is scope for further development of procedures;
There are a few improvements that should be made to sample handling and the AQC, but the laboratory has made some changes since the date of the samples. Water quality has been monitored by appropriate techniques and analytical results, with one exception, should be representative of the water supplies from which they were taken. Where breaches have been detected the Company has investigated; and
The Public Record has been maintained up to date.
Contraventions of regulations 21(2)(c) in respect of storage of samples and 29(1)(f) in respect of the public record were identified. However remedial action was to be taken speedily, so enforcement action was not necessary.
Review of procedures for operation and maintenance of the distribution network
In December 2000, Consultants Binnie, Black and Veatch working under the direction of Mr W M Waite, Principal Inspector carried out a follow up investigation of the recommendations made during the 1999 audit of the Review of Procedures for Operation and Maintenance of the Distribution Network. Based on their report Mr Waite concluded that:
the company’s responses to all the recommendations, except one, are considered adequate; and
the response to one recommendation was considered inadequate and the Company should extend its procedures to provide 'Guidance on the procedure for monitoring of valve status by monthly downloading of loggers and subsequent analysis of inconsistencies in flows and site visit (System for Classifying, Recording, Marking and Monitoring Valve Status)'.
Inspection of distribution system improvement programme progress
In October 2000, Consultants John Champion Ltd, represented by Mr W Eden, working under the direction of Mr P Halton, Inspector, carried out an audit of the Company’s progress with the mains renovation set out in the distribution Undertaking submitted by the Company. Based on Mr Eden’s report, Mr Halton concluded that:
the objectives of the undertaking remained valid;
the steps to be taken were defined with adequate precision;
a practicable timetable had been set; and
the Company was likely to meet the target renovation length by the date for completion of the work.
As a result of these inspections, 16 recommendations were conveyed to the Company for formal response, the majority of them concerning analytical matters. The Company is taking action or has already taken action on a number of the recommendations.
Improvement programmes
Three undertakings in respect of improvement programmes accepted by the Secretary of State from the Company were due for full completion or the completion of major steps during 2000 and all of these were completed on schedule.
The ongoing distribution system improvement programmes due for completion in 2010, which have been implemented by the Company, have been progressing satisfactorily.
Incidents
Sixteen of the events notified during 2000 by the Company to the Secretary of State under the terms of the Water Undertakers (Information) Direction 1998 were regarded by the Inspectorate as constituting incidents in which drinking water quality demonstrably deteriorated.
Seven incidents have been assessed. Three of these involved the supply of discoloured water to parts of Bradford in January, March and October; one involved the supply of discoloured water to part of Ripon in August; and one the supply of discoloured water to part of Sheffield in January. A further incident involved wholesomeness concerns following low level bacteriological failures in the water leaving Oughtershaw water treatment works in May. The final incident to be assessed involved a reduction in chlorination at Gorpley water treatment works in September. The Company took all reasonable steps to protect consumers during each of the above incidents and has also responded positively to the recommendations made by the Inspectorate.
Nine incidents remain under consideration. Three of these relate to wholesomeness concerns associated with the quality of water leaving water treatment works and the remainder relate to the supply of discoloured water following the disturbance of mains sediments.
No other events regarded as constituting incidents came to the attention of the Inspectorate in 2000.
Also during 2000, assessments were completed of three incidents involving the supply of discoloured water to parts of Barnsley in July 1999, parts of Bradford in August 1999 and parts of Mirfeld in October 1999. The assessment was also completed of the incident relating to taste, odour and discolouration problems following the commissioning of the new Tophill Low water treatment works in June 1999.
Prosecutions
On 5 December 2000 the Company pleaded guilty at Leeds Crown Court to offences under Section 70 of the Water Industry Act 1991 of supplying water unfit for human consumption during four incidents that occurred in 1998. The Company pleaded not guilty to charges relating to three other incidents that occurred in 1997 and 1998 but the trial judge, His Honour Judge Norman Jones QC, ordered that these should remain on the file. The Company was fined a total of £119,000 with £125,598 costs.
All seven incidents involved the supply of discoloured water. The four incidents to which the Company pleaded guilty affected the Sheepscar area of Leeds in May 1998, when planned work on part of the distribution system resulted in historic mains sediments being scoured by a sudden change in flow; parts of Drighlington in June 1998, when problems arose during a series of planned overnight tests on part of the distribution system; parts of the Idle Hill area of Bradford in July 1998, following the planned return to supply of Idle Hill service reservoir after several years out of supply to allow extensive refurbishment; and parts of Marton cum Grafton and Boroughbridge in November 1998, following serious operational problems at Marton water treatment works when planned work on the raw water source scoured deposits in the raw water main.
The three incidents to which Yorkshire Water pleaded not guilty affected parts of West Leeds in March 1997, following structural failure of a new section of main at Headingley water treatment works; the supply of discoloured water to parts of West Sheffield in December 1997 following a treatment failure at Redmires water treatment works; and the supply of discoloured water to parts of Addingham in August 1998 following a treatment failure at Addingham water treatment works.
In all cases consumers rejected the water supplied on the grounds of appearance. There were no bacteriological failures associated with the incidents and there would have been no risk to public health.
The Company has revised many of its procedures following these incidents and has taken appropriate remedial action to minimise the risk of them recurring.
Enforcement action
Table 26.4 summarises enforcement action under consideration for the Company as a result of the Inspectorate's work in, or pertaining to, the calendar year 2000.
table 26.1 Yorkshire Water Services Limited
MICROBIOLOGICAL QUALITY OF WATER LEAVING TREATMENT WORKS2000 1999 1998 Number of water treatment works 121 127 121 Works with no sampling shortfall 120 127 121 COLIFORMS Total number of determinations 12,024 14,061 14,553 - number containing coliforms 6 11 14 - % containing coliforms <0.1 0.1 0.1 Treatment works with coliforms detected 5 10 12 - % of all works 4 8 10 FAECAL COLIFORMS Total number of determinations 12,024 14,062 14,553 - number containing faecal coliforms 3 3 6 - % containing faecal coliforms <0.1 <0.1 <0.1 Treatment works with faecal coliforms detected 2 3 6 - % of all works 2 2 5
table 26.2 Yorkshire Water Services Limited
MICROBIOLOGICAL QUALITY OF WATER IN SERVICE RESERVOIRS2000 1999 1998 Number of service reservoirs 432 421 420 Service reservoirs with no sampling shortfall 432 419 420 COLIFORMS Total number of determinations 21,162 20,862 20,955 - number containing coliforms 27 37 87 - % containing coliforms 0.1 0.2 0.4 Service reservoirs with coliforms detected 25 31 68 Service reservoirs with coliforms detected in more than 5% of samples 0 2 6 - % of all service reservoirs 0 <1 1 FAECAL COLIFORMS Total number of determinations 21,162 20,826 20,955 - number containing faecal coliforms 10 6 13 - % containing faecal coliforms <0.1 <0.1 0.1 Service reservoirs with faecal coliforms detected 9 6 12 - % of all service reservoirs 2 1 3
table 26.3 Yorkshire Water Services Limited
WATER QUALITY IN SUPPLY ZONESColumns 'CBU' show, for determinations, contraventions covered by undertakings and, for zones, the total number of zones covered by undertakings in 2000. Column 'E' shows the number of zones for which new enforcement action is under consideration as a result of contraventions of the PCV in 2000. Please refer to the Introduction to Part 2 for more detailed explanation of this table. PARAMETER DETERMINATIONS in 2000 ZONES (214 in 2000)* Total Contravening PCV Non-compliant No. % CBU CBU E Number in: 2000 2000 1999 1998 Coliforms 12,490 34 0.3 0 0 0 1 1 0 Faecal coliforms 12,490 8 0.1 0 0 0 8 11 4 Colour 12,391 3 <0.1 1 1 0 3 1 1 Turbidity 12,487 8 0.1 6 27 0 5 20 31 Odour 1,661 0 0.0 0 0 0 0 0 0 Taste 1,659 0 0.0 0 0 0 0 0 0 Hydrogen ion 12,487 17 0.1 3 6 3 10 7 13 Nitrate 1,904 0 0.0 0 0 0 0 3 2 Nitrite 1,983 42 2.1 0 0 0 8 7 3 Aluminium 6,495 14 0.2 6 32 2 11 13 13 Iron 6,533 84 1.3 82 163 0 58 54 75 Manganese 6,496 20 0.3 18 79 0 19 32 23 Lead 990 3 0.3 0 1 0 3 7 18 PAH 957 11 1.1 6 28 0 9 8 11 Trihalomethanes 1,159 8 0.7 0 19 1 3 3 12 Total pesticides 1,122 0 0.0 0 4 0 0 0 0 Diuron 1,093 0 0.0 0 4 0 0 0 1 Imazapyr 1,074 0 0.0 0 4 0 0 0 1 Isoproturon 1,093 4 0.4 4 4 0 4 4 4 MCPA 1,073 0 0.0 0 4 0 0 0 1 Mecoprop 1,093 0 0.0 0 4 0 0 4 1 Other Pesticides 81,068 0 0.0 0 4 0 0 0 0 Tetrachloroethane 1,158 0 0.0 0 0 0 0 0 0 Benzo 3,4 pyrene 967 4 0.4 0 0 0 0 0 0 Oxidizability 226 0 0.0 0 0 0 0 1 0 All others 24,788 0 0.0 0 0 0 0 0 0 TOTAL 206,937 260 0.1 126 - - - - - *209 zones in 1999; 205 zones in 1998
table 26.4 Yorkshire Water Services Limited
SUMMARY OF ENFORCEMENT ACTION CONSIDERED IN 2000Regulation reason for enforcement 3(3)(c) Contravention of the standard for hydrogen ion in three zones. 3(3)(c) Contravention of the standard for aluminium in two zones. 3(3)(e) Contravention of trihalomethanes standard in one zone. 3(7) Contravention of the faecal coliform standard at one service reservoir.
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Published 11 July 2001
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