13 NORTH WEST WATER LIMITED
Introduction
North West Water Limited supplies on average about 1,940 Ml/d of water to about 6.8 million consumers in the Lake District, the western Pennines, Merseyside, Greater Manchester, Lancashire, Cumbria and Cheshire. 92% of the Company’s water supplies come from rivers and reservoirs. The remainder comes from boreholes. The Company has 161 treatment works, and distributes water through 42,200 km of pipes and 387 service reservoirs to 305 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 340,625 determinations in 2000. Of these, 99.73% demonstrated compliance with the relevant PCV, but 921 showed a contravention to have occurred.
Coliforms were not detected at 101 (63%) of the Company's 161 water treatment works. At 386 of the Company's 387 service reservoirs, coliforms were absent from at least 95% of samples. Of the Company's 305 water supply zones in 2000, 293 (96%) complied fully with the relevant water quality standards or had breaches of the standards which were either trivial, unlikely to recur, or were fully covered by undertakings. In the other 12 (4%) of the zones, breaches could result in enforcement action.
Microbiological quality of water leaving treatment works
The Company complied with the sampling frequencies required by regulation 17 at 156 of its treatment works in 2000. Shortfalls at the other five are regarded as trivial or unlikely to recur as a result of remedial action taken by the Company.
Table 13.1 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. There has been a significant increase since 1999 in the number of treatment works, and samples from treatment works, in which total coliforms were detected. All other differences at treatment works are not considered significant.
Contraventions of the standards at 10 treatment works have resulted in the consideration of enforcement action. Failures at the remaining works are considered trivial or are unlikely to recur as a result of actions taken by the Company.
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 13.2 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences the last three years in the number of service reservoirs, and samples from service reservoirs, in which coliforms were detected are not considered significant.
Contraventions of the standards at two service reservoirs resulted in the consideration of enforcement action. Failures at the remaining works are considered trivial or are unlikely to recur as a result of actions taken by the Company.
Water quality in water supply zones
The Company complied with the required sampling frequencies for all parameters in all zones.
Table 13.3 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 standards for iron, lead, turbidity, and pH, but significant increases since 1999 in the number of zones failing to comply with the standards for ammonium 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 13.3 and 13.4. All other contraventions of the standards in zones are considered trivial, unlikely to recur as a result of the Company’s actions, or a covered by undertakings.
Inspection
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.
Follow-up of response to recommendations and audit of arrangements for Cryptosporidium sampling
The Inspectorate audited the Company’s arrangements and follow up to recommendations and 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; and
The analytical results have appeared on the Public Record, but the date when they were placed there is not recorded. There are a number of omissions and minor differences between the values on the record and in the laboratory database.
Contraventions of regulation 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.
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 and analytical arrangements are generally satisfactory. The analytical results have appeared on the Public Record, but the date when they were placed there is not recorded. There are a number of omissions and minor differences between the values on the record and in the laboratory database.
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 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:
to provide adequate responses to those responses to recommendations that are considered inadequate, the company extend its procedures to provide the following:
A formal flushing policy and a comprehensive flushing procedure (Policy for the pre-emptive flushing of mains and its implementation – Recommendation R3.1); and
Guidance on the need for monitoring of valve status by annual pressure zero testing and subsequent actions to be taken (ie the need for valve status to be checked and altered if appropriate) (System for Classifying, Recording, Marking and Monitoring Valve Status – Recommendation R8.4)
Inspection of distribution system improvement programme progress
In September 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, 12 recommendations were conveyed to the Company for formal response, concerning arrangements for Cryptosporidium sampling, operation and maintenance of the distribution network and the public record. The Company is taking action or has already taken action on most 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.
The ongoing distribution system improvement programmes due for completion in 2009, which have been implemented by the Company, have been progressing satisfactorily.
Incidents
16 of the 37 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. 14 of these incidents have been assessed.
Six incidents involved the supply of discoloured water to parts of Lytham St Annes in June; parts of Harwood in October; parts of Thornton Cleveleys in October; parts of Colne in November; parts of Bury in November; and parts of Wigan in December. One incident involved wholesomeness concerns following a loss of disinfection at Bullfell water treatment works in August. Three incidents involved loss of supplies to parts of Accrington in August; to Whiston Hospital, Liverpool, in September; and parts of Bolton in October. Three incidents involved the supply of water with a taste and odour to parts of Wallasey in May; parts of Ormskirk in August; and parts of Chorley in November. One incident involved a failure in treatment at Worsthorne water treatment works in October which resulted in the supply of water with a high pH to parts of Burnley and Pendle. 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.
Two further incidents have yet to be assessed and involved increases in the reported number of cases of cryptosporidiosis in Clitheroe in March and in the South Ribble area in May.
No other events regarded as constituting incidents came to the attention of the Inspectorate in 2000.
Also during 2000, assessments were completed of 13 incidents which occurred in 1998 and 10 incidents which occurred in 1999. Thirteen incidents involved the supply of discoloured water to parts of Darwen in January 1998; parts of Rochdale in January 1998; parts of Ormskirk in March 1998; parts of Wallasey in December 1999; parts of Warrington in August and October 1998; parts of St Helens in September 1998; parts of Eccles in October 1998; parts of Rainford in November, December 1998 and February 1999; parts of Macclesfield in January 1999; and parts of Wigan in May 1999.
The assessment was also completed of 8 incidents relating to taste and odour in the water supply to parts of Cheadle Hulme in October 1998; parts of Whitworth in May 1998; parts of Oldham in May 1999; parts of Warrington in July 1999; parts of Widnes in July 1998; parts of Nantwich in January 1999 and parts of Preston and the South Ribble area in January and December 1999.
Two incidents involving an increase in the number of reported cases of cryptosporidiosis in the Chorley and South Ribble area in June 1998; and in some areas supplied in part from the Thirlmere aqueduct in April 1999 were also assessed.
Formal Cautions
As a result of the completion of the assessments of incidents, the Company was formally cautioned on separate occasions for supplying water unfit for human consumption to parts of Rochdale in January 1998; parts of Ormskirk in March 1998; parts of Whitworth in May 1998; and parts of Oldham in May 1999, contrary to Section 70 of the Water Industry Act 1991. The details of the offences will be kept on record and may be referred to, as appropriate, in the future.
Prosecutions
On 6 October 2000 the Company pleaded guilty at Wallasey Magistrates' Court to offences under Section 70 of the Water Industry Act 1991 of supplying water unfit for human consumption during the Wallasey incident in April 1998. The Company asked that three other cases associated with the St Helens (September 1998), the Eccles (October 1998) and the Rainford (February 1999) incidents be taken into consideration. The Company was fined a total of £12,000 with £10,471 costs.
On 13 October 2000 the Company pleaded guilty at Crewe Magistrates' Court to offences under Section 70 of the Water Industry Act 1991 of supplying water unfit for human consumption during the Nantwich incident in January 1999. The Company asked that two other cases associated with the Cheadle Hulme (October 1998) and the Macclesfield (January 1999) incidents be taken into consideration. The Company was fined a total of £20,000 with £7,100 costs.
Discoloured water was supplied during the Wallasey incident following planned work on the distribution system. In the St Helens incident, discoloured water was supplied following planned flushing operations and in the Eccles incident following rezoning to permit a meter installation. Discoloured water was also supplied in the Rainford incident following planned work to repair mains and in the Macclesfield incident following pump trials.
In the Nantwich incident, water supplies were contaminated with hydrocarbons following recycling of contaminated surface water to the wash water recovery system at Hurleston WTW and in the Cheadle Hulme incident, contamination with diesel oil arose following repair to burst main.
In the Nantwich and the Cheadle Hulme incidents, consumers rejected the water supplied on the grounds of its taste and odour. In the other incidents, 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 13.4 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 13.1 North West Water Limited
MICROBIOLOGICAL QUALITY OF WATER LEAVING TREATMENT WORKS2000 1999 1998 Number of water treatment works 161 176 180 Works with no sampling shortfall 156 154 180 COLIFORMS Total number of determinations 23,781 24,994 25,535 - number containing coliforms 90 42 70 - % containing coliforms 0.4 0.2 0.3 Treatment works with coliforms detected 60 32 50 - % of all works 37.3 18 28 FAECAL COLIFORMS Total number of determinations 23,781 24,994 25,534 - number containing faecal coliforms 18 8 16 - % containing faecal coliforms <0.1 <0.1 0.1 Treatment works with faecal coliforms detected 17 7 15 - % of all works 10.6 4 8
table 13.2 North West Water Limited
MICROBIOLOGICAL QUALITY OF WATER IN SERVICE RESERVOIRS2000 1999 1998 Number of service reservoirs 387 393 408 Service reservoirs with no sampling shortfall 387 366 408 COLIFORMS Total number of determinations 20,352 19,797 20,936 - number containing coliforms 53 40 58 - % containing coliforms 0.3 0.2 0.3 Service reservoirs with coliforms detected 48 39 50 Service reservoirs with coliforms detected in more than 5% of samples 1 1 1 - % of all service reservoirs 0.3 <1 <1 FAECAL COLIFORMS Total number of determinations 20,352 19,797 20,936 - number containing faecal coliforms 8 2 11 - % containing faecal coliforms <0.1 <0.1 0.1 Service reservoirs with faecal coliforms detected 5 2 10 - % of all service reservoirs 1.3 <1 2
table 13.3 North West Water 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 (305 in 2000)* Total Contravening PCV Non-compliant No. % CBU CBU E Number in: 2000 2000 1999 1998 Coliforms 19,555 127 0.6 6 0 1 3 0 1 Faecal coliforms 19,555 9 <0.1 0 0 1 9 11 7 Colour 6,632 0 0.0 0 0 0 0 0 5 Turbidity 9,284 8 0.1 2 42 0 8 19 25 Odour 3,107 0 0.0 0 0 0 0 1 3 Taste 3,085 0 0.0 0 0 0 0 0 1 Hydrogen ion 7,685 15 0.2 4 0 0 12 7 24 Nitrate 4,759 10 0.2 0 0 0 2 2 0 Nitrite 4,760 3 <0.1 0 0 0 3 5 1 Aluminium 11,215 11 0.1 0 0 0 11 18 15 Iron 11,261 229 2.0 224 257 2 108 142 152 Manganese 11,262 39 0.3 28 130 1 37 37 52 Lead 7,409 149 2.0 0 0 4 99 163 158 PAH 2,176 19 0.9 12 14 0 11 13td> 20 Trihalomethanes 3,669 103 2.8 99 107 1 37 12 46 Total pesticides 2,767 1 <0.1 0 0 0 1 1 0 Dichlorprop 1,905 0 0.0 0 0 0 0 1 0 Gamma-HCH 1,892 0 0.0 0 0 0 0 1 0 MCPA 1,905 1 <0.1 0 0 0 1 0 2 Gamma-HCH 1,892 0 0.0 0 0 0 0 1 0 Other pesticides 25,699 0 0.0 0 0 0 0 0 0 Ammonium 4,761 15 0.3 0 0 1 14 2 2 Cadmium 330 0 0.0 0 0 0 0 0 1 Copper 3921 0 0.0 0 0 0 0 1 1 Oxidizability 629 0 0.0 0 0 0 0 1 1 Phosphorus 11,504 7 <0.1 0 0 0 4 4 5 Potassium 406 0 0.0 0 0 0 0 1 5 Surfactants 342 0 0.0 0 0 0 0 0 1 Temperature 3,303 0 0.0 0 0 0 0 0 2 All others 65,676 0 0.0 0 0 0 0 0 0 TOTAL 252,359 752 0.3 375 - - - - - *308 zones in 1999; 306 zones in 1998.
table 13.4 North West Water Limited
SUMMARY OF ENFORCEMENT ACTION CONSIDERED IN 2000Regulation Reason for enforcement 3(7) Contravention of the total coliform standard at nine treatment works. 3(7) Contravention of the total and faecal coliform standards at one treatment works and one service reservoir. 3(7) Contravention of the faecal coliform standard at one service reservoir. 3(3)(c) Contravention of the standard for total and faecal coliforms in one zone. 3(3)(c) Contravention of the standard for lead in four zones*. 3(3)(c) Contravention of the standard for iron in two zones. 3(3)(c) Contravention of the standard for manganese in one zone. 3(3)(c) Contravention of the standard for ammonium in one zone. 3(3)(e) Contravention of the standard for THM in one zone. *Breaches of the standard for lead in a further 22 zones are already covered by a Regulatory Programme of Work submitted by the Company under Regulation 41 of the 2000 Regulations.
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Published 11 July 2001
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