Chief Inspector's Report 2002
17 South West Water Limited
| Overall Water Quality supplied by South West Water Limited in 2002 | |||||||||||||||||||||||
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Water Quality at Treatment Works, in Service Reservoirs and in Water Supply Zones
To be wholesome, water must comply with the standards for the parameters set out in the Water Supply (Water Quality) Regulations 1989. In 2002, the Company carried out a total of 172,739 tests on samples taken at water treatment works, from service reservoirs and in water supply zones and of these, 99.92% complied with the relevant water quality standards set down in the Regulations. A list of the parameters, the relevant standards and their significance can be found at the beginning of this section.
Water Quality leaving Treatment works
2002 |
2001 |
2000 |
||
| Number of water treatment works | 34 |
35 |
36 |
|
| COLIFORMS | ||||
| Total number of tests | 7,592 |
8,217 |
8,085 |
|
| - | number containing coliforms | 2 |
10 |
10 |
| - | % containing coliforms | 0.03% |
0.12% |
0.12% |
| Treatment works with coliforms detected | 1 |
7 |
10 |
|
| - | % of all works with coliforms detected | 2.94% |
20.00% |
27.78% |
| FAECAL COLIFORMS | ||||
| Total number of tests | 7,593 |
8,221 |
8,086 |
|
| - | number containing faecal coliforms | 0 |
0 |
1 |
| - | % containing faecal coliforms | 0.00% |
0.00% |
0.01% |
| Treatment works with faecal coliforms detected | 0 |
0 |
1 |
|
| - | % of all works with faecal coliforms detected | 0.00% |
0.00% |
2.78% |
The Inspectorate is monitoring the situation at one works where there were failures of the coliform standard. There were no failures of the faecal coliform standard at any works. There has been a significant decrease since 2001 in the number of treatment works and tests taken from treatment works in which total coliforms were detected. All other differences were not considered significant.
In 2002, 4,556 regulatory samples for Cryptosporidium were taken at 14 sites. Very low numbers of oocysts were detected in 22 samples from nine sites. All results were well below the treatment standard and there were no reported outbreaks of cryptosporidiosis.
Water Quality in Service Reservoirs
2002 |
2001 |
2000 |
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| Number of service reservoirs | 336 |
339 |
351 |
|
| COLIFORMS | ||||
| Total number of tests | 17,978 |
18,194 |
18,495 |
|
| - | number containing coliforms | 20 |
44 |
35 |
| - | % containing coliforms | 0.11% |
0.24% |
0.19% |
| Service reservoirs with coliforms detected | 18 |
43 |
30 |
|
| Service reservoirs with coliforms detected | 2 |
0 |
2 |
|
| in more than 5% of tests | ||||
| - | % of all service reservoirs with coliforms detected | 0.60% |
0.00% |
0.57% |
| FAECAL COLIFORMS | ||||
| Total number of tests | 17,986 |
18,218 |
18,510 |
|
| - | number containing faecal coliforms | 1 |
5 |
5 |
| - | % containing faecal coliforms | 0.01% |
0.03% |
0.03% |
| Service reservoirs with faecal coliforms detected | 1 |
5 |
5 |
|
| - | % of all service reservoirs with faecal coliforms detected | 0.30% |
1.47% |
1.42% |
There were failures of the coliform standard at two service reservoirs and the faecal coliform standard at one of these reservoirs. However, the Company has taken action to prevent the failures recurring. There has been a significant decrease since 2001 in the number of services reservoirs and tests taken from service reservoirs in which total coliforms were detected. All other differences were not considered significant.
Water Quality in Water Supply Zones
The table below shows the data for the key parameters and any other parameters where there was a failure of the standard. All other parameters were fully compliant.
| Parameter | Total number of tests |
Tests not meeting the prescribed concentration or value |
Number of failures covered by Undertakings |
Number of zones not complying with the standards |
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No |
% |
2002 |
2001 |
2000 |
|||
Coliforms |
5,003 |
27 |
0.54 |
0 |
0 |
0 |
0 |
Faecal coliforms |
5,005 |
1 |
0.02 |
0 |
1 |
1 |
2 |
Colour |
2,751 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Turbidity |
2,751 |
0 |
0.00 |
0 |
0 |
2 |
1 |
Odour |
920 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Taste |
919 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Hydrogen
ion |
2,751 |
1 |
0.04 |
0 |
1 |
1 |
3 |
Nitrate |
1,143 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Nitrite |
1,143 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Aluminium |
2,751 |
0 |
0.00 |
0 |
0 |
1 |
0 |
Iron |
2,751 |
46 |
1.67 |
42 |
29 |
36 |
37 |
Manganese |
2,751 |
7 |
0.25 |
5 |
4 |
9 |
8 |
Lead |
517 |
3 |
0.58 |
0 |
3 |
2 |
2 |
PAH |
489 |
32 |
6.54 |
20 |
14 |
17 |
11 |
Trihalomethanes |
428 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Total pesticides |
1,534 |
0 |
0.00 |
0 |
0 |
0 |
0 |
2,4-D |
1,457 |
0 |
0.00 |
0 |
0 |
11 |
0 |
Other pesticides |
62,885 |
0 |
0.00 |
0 |
0 |
0 |
0 |
Benzo-3,4-pyrene |
489 |
0 |
0.00 |
0 |
0 |
1 |
0 |
All others |
18,596 |
0 |
0.0 |
0 |
0 |
0 |
0 |
TOTAL |
117,034 |
117 |
0.10% |
67 |
|||
| 81 zones in 2000, 2001 and 2002 | |||||||
The fifth column indicates the number of failures in zones already covered by legally binding undertakings given by the Company. These undertakings require remedial work to be carried out to ensure compliance with the individual standard.
The New Regulations
In 2002, the Company carried out monitoring for the six new parametric values set down in the new Water Supply (Water Quality) Regulations 2000. These Regulations come into force on 25 December 2003. The results are shown in the table below.
| Parameter | Total number of tests |
New standard |
Tests not meeting the new standard |
| Benzene | 229 |
1.0 µg/l |
0 |
| Bromate | 397 |
10.0 µg/l |
0 |
| 1,2 dichloroethane | 229 |
3.0 µg/l |
0 |
| Nitrite (ex-water treatment works) | 331 |
0.1 mg/l |
0 |
| Clostridium perfringens | 190 |
0/100 ml |
0 |
| Enterococci | 399 |
0/100 ml |
0 |
Compliance data for 2002 has also been analysed against the revised standards and the results are shown in the following table.
| Parameter | Total number or tests |
Current Standard |
Number of tests not meeting current standard |
Revised Standard |
Number of tests not meeting revised standard |
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| Antimony | 81 |
10.0 µg/l |
0 |
5.0 µg/l |
0 |
|||
| Arsenic | 81 |
50.0 µg/l |
0 |
10.0 µg/l |
0 |
|||
| Boron | 81 |
2.0 mg/l |
0 |
1.0 mg/l |
0 |
|||
| Copper | 416 |
3.0 mg/l |
0 |
2.0 mg/l |
0 |
|||
| Lead | 517 |
50.0 µg/l |
3 |
25.0 µg/l1 |
7 |
|||
10.0 µg/l2 |
32 |
|||||||
| Nickel | 81 |
50.0 µg/l |
0 |
20.0 µg/l |
0 |
|||
| Nitrite (at consumers' taps) | 1,143 |
0.1 mg/l |
0 |
0.5 mg/l |
0 |
|||
| PAH | 489 |
0.2 µg/l |
32 |
0.1 µg/l |
0 |
|||
| Tetrachloroethene | 428 |
30.0 µg/l |
|
10.0 µg/l
|
0
|
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| Trichloroethene | 428 |
10.0 µg/l |
Details of the new and revised standards, and the reasons for the revised standards where applicable, can be found in chapter J "New Regulations and Associated Programmes of Work".
1 From 25.12.03
2 From 25.12.13
Company Audit and Inspection
The Company was inspected or audited by the Inspectorate or its appointed consultants on a number of occasions during 2002. Where relevant, report summaries are available in the 'Business and Technical' section of the Inspectorate's web site under 'Audit and Inspection'.
| Audit or Inspection | Date |
| Audit of regulatory Cryptosporidium monitoring sites | Various dates throughout the year |
| Review of plumbosolvency treatment and control programmes of work | January 2002 |
| Unannounced inspection of laboratory analysing for Cryptosporidium | March 2002 |
| Audit of regulatory Cryptosporidium sampler | March 2002 |
| Audit of regulatory programmes of work | March 2002 |
| Inspection of one water treatment works and one service reservoir | July 2002 |
| Audit of response to selected consumer complaints | July 2002 |
| Review of the distribution system undertaking | October 2002 |
| Audit trails of ten test results | November 2002 |
| Audit of regulatory sampler | November 2002 |
A number of recommendations were made in respect of action required to avoid the risk of a breach of a regulatory duty. These recommendations were in relation to the audit trails, the treatment works, sampling, distribution audit, plumbosolvency treatment for lead and the Cryptosporidium laboratory.
Incidents
The Inspectorate regarded five of the events notified during 2002 by the Company as incidents. For further details on the classification of incidents, see chapter C "Events affecting Water Quality" in Part 3.
Four of the incidents have been assessed by the Inspectorate. Each was of short duration and the Company has taken appropriate remedial action. A number of recommendations were made regarding notification, liaison and other procedures.
One incident assessment from 2002 remains under consideration.
| Nature of incident | No. of incidents |
Assessment completed |
Area affected |
Population potentially affected |
Supply of discoloured
water |
3 |
Yes No Yes |
Wadebridge (February), Looe (February), Bideford (March) |
9,000 4,000 30,000 |
Visual/Chemical contamination
of supplies (through raw water) |
1 |
Yes |
Wendron (April) |
14,000 |
Microbiological contamination of supplies |
1 |
Yes |
Heamoor (August) |
1,375 |
Enforcement Action
The table below indicates areas where, in 2002, 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 | 3(3)(c) | St Columb Major water supply zone |
Undertaking accepted |
Undertakings and other Improvement Programmes
Water treatment works and service reservoirs
Eleven statements of intent to reduce the risk of Cryptosporidium breaching the treatment standards were due for completion during 2002. Five schemes were completed on schedule. A further three schemes were completed after minor delays during commissioning. Two schemes were delayed due to significant revision of the schemes and the remaining scheme was delayed because of a ground collapse on the site.
No other improvement programmes were due for completion during 2002.
Distribution
The ongoing distribution system undertaking has been progressing satisfactorily. During 2002, 390 km of mains have been renovated. The Company is required to renovate a further 4,789 km of mains by December 2010.
Lead
The Company has a Regulation 41 programme of work to meet the revised standard for lead set down in the new Water Supply (Water Quality) Regulations 2000, which will come into force on 25 December 2003. Progress with the delivery of the programmes is monitored by the Inspectorate and has been satisfactory.
