7 Dŵr Cymru Cyfyngedig
Overall Water Quality supplied by Dŵr Cymru Cyfyngedig in 2001
- A total of 160,873 tests were carried out by Dŵr Cymru Cyfyngedig in 2001.
- Of these tests, 99.76% complied with the Regulations.
Company Information
Amount of Water Supplied: 1,000 Ml/d
Consumers Supplied: 2.8 million
Areas of Supply: Most of Wales and parts of Hereford and Worcester and Gloucestershire
Water Composition: 94% from rivers and reservoirs
6% from boreholes and aquifers
Treatment Works: 104
Service Reservoirs: 558
Km of Mains: 24,900
Water Supply Zones: 177Water Quality in Water Supply Zones, at Treatment Works, and in Service Reservoirs
Water supply zones
- To be wholesome, water must comply with the standards set out in the Regulations. The Company carried out a total of 81,767 tests on samples taken in its 177 water supply zones. The table below includes only the parameters that breached the standard; all other parameters were fully compliant with the standards. A list of these parameters and their significance 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. These undertakings required remedial work to be carried out to ensure compliance with the individual standard.
*Most of these failures did not contravene the new standard for nitrite set down in the new Water Supply (Water Quality) Regulations 2000 (2001 for Wales).
Parameter Total samples taken Samples not meeting the standard Percentage Number of failures already covered by undertakings Total coliforms 8,806 17 0.19 0 Faecal coliforms 8,807 3 0.03 0 Turbidity 3,353 3 0.09 3 Hydrogen ion 1,359 6 0.44 5 Odour 1,138 4 0.35 0 Nitrite 1,808 160* 8.85 0 Aluminium 1,626 4 0.25 2 Iron 4,273 52 1.22 46 Manganese 2,185 8 0.37 6 Lead 1,237 10 0.81 0 PAH 970 35 3.61 29 Trihalomethanes 628 29 4.62 7 Atrazine 723 2 0.28 0 Isoproturon 406 3 0.74 3 Mecoprop 386 1 0.26 0 Benzo-3,4-pyrene 970 3 0.31 0
Treatment works
- Of the Company's 104 treatment works, 99 (95%) complied fully with the relevant standards. Failures of the standards at a total of five works were considered trivial. Differences over the last three years in the number of treatment works, and samples from treatment works, in which coliforms were detected, were not considered significant.
Service reservoirs
- At 557 (99.8%) of the Company's 558 service reservoirs, coliforms were absent from at least 95% of samples. The service reservoir in question has since been removed from supply. Failures of the faecal coliform standard at a further seven service reservoirs were considered trivial. There has been a significant decrease since 2000 in the number of service reservoirs, and samples from service reservoirs, in which total coliforms were detected. All other differences were not considered significant.
Cryptosporidium
- The Company carried out a total of 7,881 tests on samples taken from 25 sites. Very low numbers of oocysts were detected in 576 (7.3%) samples taken from 18 sites. All results were well below the treatment standard and there were no associated outbreaks of cryptosporidiosis.
Company Audit and Inspection
- The Company was inspected or audited by the Inspectorate or its appointed consultants on a number of occasions during 2001. Where relevant, report summaries are available in the 'Business and Technical' section of the web site under 'Audit and Inspection'.
Audit or Inspection Date Audit of incident notification procedures
February Review of plumbosolvency treatment and control programmes of work
October Review of policies and procedures on contaminated land
November Audit of procedures for compliance with Regulation 25
November Inspection of one water treatment works and two service reservoirs
November Review of progress with the distribution system undertaking
November Audit trails of ten samples November/December Audit of each Cryptosporidium sampling site Various dates during the year
- Twenty-one recommendations were made in respect of action required to avoid the risk of a breach of a regulatory duty. These recommendations were mainly in relation to the audit trails and the Company's procedures for incident notification.
- Five recommendations for improvements were made in respect of the distribution undertaking and plumbosolvency treatment for lead.
Incidents
- The Inspectorate regarded 15 of the events notified during 2001 by the Company as drinking water incidents. For further details on the classification of incidents see Chapter C, 'Events affecting Water Quality', in Part 3.
- Thirteen of the incidents have been assessed by the Inspectorate. Each was of short duration and the Company has taken appropriate remedial action. Eight recommendations were made to the Company mainly regarding sampling and notification.
- During the 2001 reporting period, assessment was also completed for two incidents which occurred in 2000. During the audit of incident notification procedures carried out in February 2001, the Inspectorate became aware of a further incident that occurred in October 2000. This has also been assessed and is included in the table below.
- Two incident assessments from 2001 remain under consideration, together with three from 2000.
Nature of incident
No. of incidents Assessment completed by DWI Areas affected Supply of discoloured water
5 Yes Rhonda Valley (January); Tylorstown
(Occurred October 2000, notified February 2001); Pembrokeshire (July); Haverfordwest (August); Treorchy (November)
Vandalism 3 Yes Cefn Mabley (August); Newbridge (November); Mount Libanus (November) Taste and Odour problems 2 No Hereford (May); Swansea and Carmarthen (May) Treatment problems 1 Yes Llyswen (January) Loss of supply 1 Yes Deiniolen (January) High THM levels 1 Yes Llanfairfechan (September) Precautionary adviceto boil water 2 Yes Penyfford (August); St Nicholas (October) Prosecutions
- The Inspectorate initiated one prosecution against Dwˆr Cymru in relation to a discoloured water incident which occurred in 2000 and affected parts of Merthyr Tydfil. The Company pleaded guilty to supplying water unfit for human consumption. Further information can be found in Chapter C, 'Events affecting Water Quality', in Part 3.
Improvement Programmes
Three remedial programmes were due for completion during 2001. These were to install treatment at Garndolbenmaen WaterTreatment Works to remove Cryptosporidium; install treatment at Felindre Water Treatment Works to remove manganese, and the installation of a new raw water main at Capel Curig Water Treatment Works to reduce the risk of Cryptosporidium. Two programmes of work were completed on schedule. The third, at Capel Curig, was delayed by less than a month due to the Foot and Mouth Disease Outbreak restrictions.
The Inspectorate is currently discussing with the Company progress made to date with its ongoing distribution system improvement programme, which is behind schedule due to the impact of the Foot and Mouth Disease Outbreak and, therefore, beyond the control of the Company. During 2000 and 2001, 656 km of mains have been renovated. The Company is required to renovate a further 4,131 km of mains by March 2010.
The Company has agreed programmes of work to meet the new and revised standards set down in the new Water Supply (Water Quality) Regulations 20001, which will come into force on 25 December 2003. These relate to trihalomethanes at two sites, and bromate at one site, plus additional work required to meet the new standard for lead. Progress with delivery of the programmes is monitored by the Inspectorate, and has been satisfactory.
Enforcement Action
- The table below indicates areas where, in 2001, the Inspectorate considered taking enforcement action for regulatory breaches, and where an undertaking was submitted or where the Company took appropriate action.
Parameter/Area Regulation breached Location Outcome Iron, manganese, aluminium and turbidity Reg 3(3)(c) Tynywaun district zone To be included in the distribution undertaking Odour Reg 3(3)(c) Eithinfynydd Outcome pending
table 7.1 Dŵr Cymru Cyfyngedig
MICROBIOLOGICAL QUALITY OF WATER LEAVING TREATMENT WORKS2001 2000 1999 Number of water treatment works 104 109 111 Works with no sampling shortfall 104 103 111 COLIFORMS Total number of determinations 11,114 12,973 14,647 - number containing coliforms 5 7 10 - % containing coliforms <0.1 <0.1 <0.1 Treatment works with coliforms detected 5 6 8 - % of all works 4.8 5.5 7.2 FAECAL COLIFORMS Total number of determinations 11,114 12,973 14,647 - number containing faecal coliforms 0 2 0 - % containing faecal coliforms <0.1 <0.1 <0.1 Treatment works with faecal coliforms detected 0 2 0 - % of all works 0.00 1.83 0.00
table 7.2 Dŵr Cymru Cyfyngedig
MICROBIOLOGICAL QUALITY OF WATER IN SERVICE RESERVOIRS2001 2000 1999 Number of service reservoirs 558 564 572 Service reservoirs with no sampling shortfall 553 552 572 COLIFORMS Total number of determinations 28,441 29,412 30,461 - number containing coliforms 38 66 59 - % containing coliforms 0.1 0.2 0.2 Service reservoirs with coliforms detected 34 56 53 Service reservoirs with coliforms detected in more than 5% of samples 1 2 1 - % of all service reservoirs 0.2 0.4 0.2 FAECAL COLIFORMS Total number of determinations 28,437 29,410 30,461 - number containing faecal coliforms 7 12 17 - % containing faecal coliforms <0.1 <0.1 0.1 Service reservoirs with faecal coliforms detected 7 11 15 - % of all service reservoirs 1.3 2 3
table 7.3 Dŵr Cymru Cyfyngedig
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 2001. Column 'E' shows the number of zones for which new enforcement action is under consideration as a result of contraventions of the PCV in 2001. PARAMETER DETERMINATIONS in 2001 ZONES (177 in 2001)* Total Contravening PCV Non-compliant No. % CBU CBU E Number in: 2001 2001 2000 1999 Coliforms 8,806 17 0.2 0 0 0 0 0 0 Faecal coliforms 8,807 3 <0.1 0 0 0 3 3 2 Colour 844 0 0.0 0 0 0 0 0 0 Turbidity 3,353 3 <0.1 3 3 0 3 0 1 Odour 1,138 4 0.4 0 0 1 3 1 3 Taste 965 0 <0.1 0 0 0 0 1 1 Hydrogen ion 1,359 6 0.4 5 2 0 3 2 3 Nitrate 1,792 0 0.0 0 0 0 0 0 0 Nitrite 1,808 160 8.9 0 0 0 26 29 30 Aluminium 1,626 4 0.3 2 1 0 3 3 3 Iron 4,273 52 1.2 46 34 0 40 37 37 Manganese 2,185 8 0.4 6 5 0 7 8 8 Lead 1,237 10 0.8 0 0 0 10 3 3 PAH 970 35 3.6 29 16 0 21 24 33 Trihalomethanes 628 29 4.6 7 3 0 9 2 6 Total pesticides 1,164 0 0.0 0 0 0 0 0 2 Altrazine 723 2 0.3 0 0 0 2 0 2 2,4-D 386 0 0.0 0 0 0 0 0 1 Carbendazim 318 0 0.0 0 0 0 0 0 1 Isoproturon 406 3 0.7 3 3 0 3 0 0 Linuron 406 0 0.0 0 0 0 0 0 1 Mancozeb 24 0 0.0 0 0 0 0 0 1 MCPA 376 4 0.0 0 0 0 0 3 1 Mecoprop 386 1 0.3 0 0 0 1 0 1 Simazine 722 0 0.0 0 0 0 0 1 0 Other pesticides 16,102 0 0.0 0 0 0 0 0 0 Benzo 3,4 Pyrene 970 3 0.3 0 0 0 1 1 0 Oxidizability 202 0 0.0 0 0 0 0 0 1 Surfactants 186 0 0.0 0 0 0 0 1 0 All others 19,605 0 0.0 0 0 0 0 0 0 TOTAL 81,767 340 0.4 101 - - - - - *183 zones in 2000; 184 zones in 1999.
1 The new Water Supply (Water Quality) Regulations 2001 in Wales. GO BACK TO PARAGRAPH
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Drinking Water Inspectorate,
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Telephone : 020 7944 5956 - Facsimile : 020 7944 5969
E-mail: dwi.enquiries@defra.gsi.gov.uk
Published 10 July 2002
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