24 THREE VALLEYS WATER PLC
Introduction
Three Valleys Water plc supplies on average about 699 Ml/d of water to about 2.4 million consumers in parts of Bedfordshire, Berkshire, Buckinghamshire, Essex, Hertfordshire and several London Boroughs. 67% of the Company’s water supplies come from boreholes. The remainder comes from the River Thames and a bulk supply of treated water from Anglian Water Services Limited. The Company has 77 treatment works, and distributes water through 11,000 km of pipes and 117 service reservoirs to 98 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 82,027 determinations in 2000. Of these, 99.88% demonstrated compliance with the relevant PCV, but 100 showed a contravention to have occurred.
Coliforms were not detected at 69 (90%) of the Company's 77 water treatment works. At all of the Company's 117 service reservoirs, coliforms were absent from at least 95% of samples. Of the Company's 98 water supply zones in 2000, all complied fully with the relevant water quality standards or had breaches of the standards which were either trivial or were fully covered by undertakings.
Microbiological quality of water leaving treatment works
The Company complied with the sampling frequencies required by regulation 17 at 73 of its 77 treatment works in 2000. Shortfalls at the other four are regarded as unlikely to recur as a result of improvements to procedures and systems carried out by the Company.
Table 24.1 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.
Microbiological quality of water in service reservoirs
The Company complied with the sampling frequencies required by regulation 18 at 116 of its 117 service reservoirs in 2000. The shortfall at the one remaining service reservoir is regarded as unlikely to recur as a result of improvements to procedures and systems carried out by the Company.
Table 24.2 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 are considered trivial.
Water quality in water supply zones
The Company failed to comply with the required sampling frequencies for various parameters in nine zones. Shortfalls are either considered trivial or are regarded as unlikely to recur as a result of improvements to procedures and systems carried out by the Company.
Table 24.3 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences over the last three years are not considered statistically significant.All contraventions of the standards in zones are considered trivial or are covered by undertakings.
Inspection
Follow-up of response to recommendations and audit of arrangements for Cryptosporidium sampling
The Inspectorate audited Three Valleys Water plc on three occasions in January, October 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;
The sampling arrangements are generally satisfactory, but there are a number of problems with analytical arrangements and following communication procedures when a result breaches the PCV;
The analytical results may have appeared on the Public Record in time, but the date is not recorded. The printout of the public record does not make it clear that an amendment has been made or that there is more data to follow. The archaic format of the printout is not user-friendly;
Contraventions of regulation 21(2)(c) in respect of storage of samples, 21(2)(d)(iii) in respect of one parameter and 29(1)(f) in respect of the public record. However remedial action was to be taken speedily, so enforcement action was not necessary.
Audit of plumbosolvency treatment and control programmes of work
In November 2000, Consultants WS Atkins, represented by Mr S Ntifo, 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 Ntifo’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’s proposed steps to be taken and the proposed completion dates are generally sound.
Audit trails of five samples
Mr R M Walls, Consultant, working under the direction of Mr W M Waite, Principal Inspector carried out audit trails on five samples chosen at random. Based on Mr Walls report Mr Waite concluded that:
the sampling arrangements are generally satisfactory, but there are a number of problems with analytical arrangements and following communication procedures when a result breaches the PCV. The analytical results may have appeared on the Public Record in time, but the date is not recorded. The printout of the public record does not make it clear that an amendment has been made or that there is more data to follow. The archaic format of the printout is not user-friendly.
Inspection of distribution system improvement programme progress In November 2000, Consultants RPS, represented by Mr J Sim, 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 Sim’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, 13 recommendations were conveyed to the Company for formal response, nearly half of them concerning arrangements for Cryptosporidium sampling. The Company is taking action or has already taken action on a number of the recommendations.
Improvement programmes
No 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.
Relaxations
The Secretary of State had authorised a relaxation of the PCV for potassium in all zones supplied from the Dunmow borehole, subject to review by 31 December 1999. As a result of the review initiated by the Inspectorate in November 1999 the relaxation has been renewed subject to review by 25 December 2003.
Incidents
Nine of the 24 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. All incidents have been assessed.
Three incidents involved the supply of discoloured water to parts of Watford in January; to the villages of Ongar, Moreton, High Laver, Matching Green and Fyfield in March; and to parts of Kings Langley in April. Four incidents involved wholesomeness concerns following low level bacteriological failures in the water supply to part of Watford in June; to parts of Watton at Stone in July; to parts of Wembley in August; and to parts of Whetstone in October. A further incident involved the loss of supplies to parts of Eaton Bray in March. One incident involved contamination of a raw water source at Hatfield in June. 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.
No other events regarded as constituting incidents came to the attention of the Inspectorate in 2000.
Also during 2000, assessments were completed of six incidents which occurred the previous year. Three incidents involved wholesomeness concerns following low level bacteriological failures in the water supply to parts of Ongar in August 1999; parts of Toothill and Greensted in August 1999; and parts of Digswell in September 1999. One incident involved the supply of discoloured water to parts of Sheering in November 1999. The assessment was also completed of two incidents relating to taste and odour in the water supply to parts of Stapleford in June 1999 and to parts of Stanstead in November 1999.
Cautions
The Company was formally cautioned for supplying water unfit for human consumption to the villages of Ongar, Moreton, High Laver, Matching Green and Fyfield in March 2000, contrary to Section 70 of the Water Industry Act 1991. The details of the offence will be kept on record and may be referred to, as appropriate, in the future.
Enforcement action
No enforcement action needed to be considered for the Company as a result of the Inspectorate's work in, or pertaining to, the calendar year 2000.
table 24.1 Three Valleys Water plc
MICROBIOLOGICAL QUALITY OF WATER LEAVING TREATMENT WORKS2000 1999 1998 Number of water treatment works 77 76 76 Works with no sampling shortfall 73 72 73 COLIFORMS Total number of determinations 7,857 7,351 6,723 - number containing coliforms 10 5 5 - % containing coliforms 0.1 0.1 0.1 Treatment works with coliforms detected 8 5 5 - % of all works 10 7 7 FAECAL COLIFORMS Total number of determinations 7,857 7,351 6,723 - number containing faecal coliforms 2 0 1 - % containing faecal coliforms <0.1 0.0 <0.1 Treatment works with faecal coliforms detected 2 0 1 - % of all works 2.6 0 1
table 24.2 Three Valleys Water plc
MICROBIOLOGICAL QUALITY OF WATER IN SERVICE RESERVOIRS2000 1999 1998 Number of service reservoirs 117 117 120 Service reservoirs with no sampling shortfall 116 114 117 COLIFORMS Total number of determinations 5,928 6,069 6,106 - number containing coliforms 10 4 17 - % containing coliforms 0.2 0.1 0.3 Service reservoirs with coliforms detected 9 3 15 Service reservoirs with coliforms detected in more than 5% of samples 0 0 0 - % of all service reservoirs 0 0 0 FAECAL COLIFORMS Total number of determinations 5,928 6,069 6,106 - number containing faecal coliforms 1 1 3 - % containing faecal coliforms <0.1 <0.1 <0.1 Service reservoirs with faecal coliforms detected 1 1 3 - % of all service reservoirs 0.85 1 2
table 24.3 Three Valleys Water plc
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 (98 in 2000)* Total Contravening PCV Non-compliant No. % CBU CBU E Number in: 2000 2000 1999 1998 Coliforms 6,798 34 0.5 0 0 0 0 0 0 Faecal coliforms 6,798 1 <0.1 0 0 0 1 2 3 Colour 447 0 0.0 0 0 0 0 0 0 Turbidity 5,888 3 <0.1 2 26 0 3 2 1 Odour 541 0 0.0 0 0 0 0 0 0 Taste 540 0 0.0 0 0 0 0 0 0 Hydrogen ion 5,881 0 0.0 0 0 0 0 0 0 Nitrate 1,016 0 0.0 0 0 0 0 0 0 Nitrite 787 22 2.8 0 0 0 7 11 16 Aluminium 501 0 0.0 0 0 0 0 0 0 Iron 1,726 5 0.3 3 26 0 5 5 4 Manganese 479 0 0.0 0 0 0 0 0 0 Lead 520 5 1.0 0 0 0 5 4 2 PAH 246 4 1.6 0 0 0 3 9 10 Trihalomethanes 349 0 0.0 0 0 0 0 0 0 Total pesticides 609 0 0.0 0 0 0 0 0 0 Atrazine 409 3 0.7 0 0 0 3 0 1 Dichlobenil 52 0 0.0 0 0 0 0 1 0 Simazine 409 0 0.0 0 0 0 0 0 1 Other Pesticides 3,324 0 0.0 0 0 0 0 0 0 Copper 171 0 0.0 0 0 0 0 1 0 Temperature 6,656 0 0.0 0 0 0 0 1 0 All others 10,310 0 0.0 0 0 0 0 0 0 TOTAL 54,457 77 0.1 5 - - - - -
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Published 11 July 2001
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