Wessex Water Services Limited
Overall Water Quality supplied by Wessex Water in 2000
A total of 152,149 tests were carried out by Wessex Water in 2000. Of these tests, 99.93% complied with the Regulations.
Company Information Amount of Water Supplied: 385 Ml/d Consumers Supplied: 1.2 million Areas of Supply: Dorset, Somerset, and parts of Wiltshire, and Hampshire and Devon Water Composition: 20% from rivers and reservoirs
80% from boreholes and aquifersTreatment Works: 93 Service Reservoirs: 325 Km of Mains: 10,800 Water Supply Zones: 103 Water Quality in Water Supply Zones, at Treatment Works, and in Service Reservoirs
Water supply zones
- In general, to be wholesome, water must comply with the standards set out in the Regulations. The Company carried out a total of 96,408 tests on samples taken in its 103 water supply zones. The table below includes only the parameters that breached the standard. All other parameters fully complied with the standards. Parameter meanings can be found at the beginning of this section.
- The last column indicates the number of failures in zones already covered by legally binding undertakings given by the Company to carry out remedial works to overcome the difficulty in meeting the individual standard.
Parameter
Total samples taken
Samples not meeting the standard
Percentage
Number of failures already covered by undertakings
Total coliforms
4,689
21
0.45
-
Faecal coliforms
4,691
1
0.02
-
Turbidity
4,679
1
0.02
-
Nitrate
4,356
2
0.05
-
Iron
1,826
15
0.82
12
Manganese
2,195
4
0.18
-
PAH
651
19
2.92
11
Benz3,4 pyrene
647
2
0.31
-
Treatment works
Of the Company's 93 treatment works, 86 (92%) complied fully with the relevant standards. Failures of the standards for total coliforms at one works have resulted in consideration of enforcement action. All other failures at treatment works were considered trivial and unlikely to recur. There has been a significant decrease since 1999 in the number of treatment works, and samples from treatment works, in which total and faecal coliforms were detected. Service reservoirs
At 323 (99%) of the Company's 325 service reservoirs, coliforms were absent from at least 95% of samples. Failures of the standard for total coliforms at one of the remaining service reservoirs, and for faecal coliforms at five service reservoirs, were considered trivial and unlikely to recur. Enforcement action is being considered for breaches of the total coliform standards at one service reservoir. Differences in the last three years in the number of service reservoirs, and samples from service reservoirs, in which coliforms were detected are not considered significant.Company Audit and Inspection Link to expanded information (web site version)
- The Company was inspected or audited by DWI or its appointed consultants on five occasions in 2000. Where relevant, report summaries are available in the ‘Business and Technical’ section of DWI’s web site under ‘Audit and Inspection’.
Audit or Inspection
Date
Annual assessment of 1999 compliance data
April/May
Audit of plumbosolvency treatment and control programs of work
November
Audit trails of five samples
November
Review of procedures for operation and maintenance of the distribution network
November
Inspection of distribution system improvement programme progress.
Ongoing
No major deficiencies were identified but a number of recommendations were made. Incidents
- The Inspectorate regarded four of the events notified by the Company during 2000 as incidents in which drinking water quality demonstrably deteriorated.
- All of the incidents have been assessed by DWI. Each was of relatively short duration and in all cases the Company took appropriate remedial action. Nine recommendations were made to the Company, mainly regarding operations.
- During 2000 assessment was also completed for one incident that occurred in 1999 for which the Company received a formal caution. For further information please see ‘Events affecting Water Quality’ in Part 3.
Nature of Incident
No. of Incidents
Assessment by DWI Completed
Areas Affected
Supply of discoloured water
1
Yes
Sherford, Taunton (August)
Supply of water with taste and odour
1
Yes
Swanage and parts of Purbeck (February)
Failure of disinfection system
1
Yes
Batheaston Water Treatment Works (March)
Microbiological contamination
1
Yes
Churchingford (August)
Improvement Programmes
Carried Out by the Company
- No remedial programmes were due for full completion during 2000.
- The ongoing distribution system improvement programmes due for completion in 2005, which have been implemented by the Company, have been progressing satisfactorily.
Enforcement Action
- The table below indicates areas where DWI is considering, or has taken enforcement action for, breaches of regulations.
Parameter/Area
Number
Regulation Breached
Total coliforms
1 works, 1 service reservoir
Regulation 3(7)
Manganese
1 zone
Regulation 3(3)(c)
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Drinking Water Inspectorate,
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Telephone : 020 7944 5956 - Facsimile : 020 7944 5969
E-mail: dwi_enquiries@detr.gov.uk
Published 11 July 2001
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