Chief Inspector's Report 2002
4 Cambridge Water Company
| Overall Water Quality supplied by Cambridge Water Company 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 11,446 tests on samples taken at water treatment works, from service reservoirs and in water supply zones and of these, 99.84% 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 | 22 |
22 |
23 |
|
| COLIFORMS | ||||
| Total number of tests | 1,587 |
1,448 |
1,647 |
|
| - | number containing coliforms | 0 |
0 |
7 |
| - | % containing coliforms | 0.00% |
0.00% |
0.43% |
| Treatment works with coliforms detected | 0 |
0 |
5 |
|
| - | % of all works with coliforms detected | 0.00% |
0.00% |
21.74% |
| FAECAL COLIFORMS | ||||
| Total number of tests | 1,587 |
1,448 |
1,647 |
|
| - | number containing faecal coliforms | 0 |
0 |
0 |
| - | % containing faecal coliforms | 0.00% |
0.00% |
0.00% |
| Treatment works with faecal coliforms detected | 0 |
0 |
0 |
|
| - | % of all works with faecal coliforms detected | 0.00% |
0.00% |
0.00% |
All of the Company's 22 treatment works complied fully with the total coliform and faecal coliform standards. There has been a significance decrease since 2000 in the numbers of treatment works and samples from treatment works in which total coliforms were detected.
The Company has no sites that require regulatory monitoring for Cryptosporidium.
Water Quality in Service Reservoirs
2002 |
2001 |
2000 |
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| Number of service reservoirs | 33 |
33 |
33 |
|
| COLIFORMS | ||||
| Total number of tests | 1,733 |
1,787 |
1,716 |
|
| - | number containing coliforms | 1 |
1 |
5 |
| - | % containing coliforms | 0.06% |
0.06% |
0.29% |
| Service reservoirs with coliforms detected | 1 |
1 |
5 |
|
| Service reservoirs with coliforms detected | 0 |
0 |
0 |
|
| in more than 5% of tests | ||||
| - | % of all service reservoirs with coliforms detected | 0.00% |
0.00% |
0.00% |
| FAECAL COLIFORMS | ||||
| Total number of tests | 1,733 |
1,787 |
1,716 |
|
| - | number containing faecal coliforms | 0 |
0 |
0 |
| - | % containing faecal coliforms | 0.00% |
0.00% |
0.00% |
| Service reservoirs with faecal coliforms detected | 0 |
0 |
0 |
|
| - | % of all service reservoirs with faecal coliforms detected | 0.00% |
0.00% |
0.00% |
At all of the Company's service reservoirs, coliforms were absent from at least 95% of samples. There were no failures of the faecal coliform standard. Differences over the last three years in the number of service reservoirs, and in the number of tests carried out on samples from service reservoirs, in which coliforms were detected 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 |
856 |
4 |
0.47 |
0 |
0 |
0 |
0 |
|
Faecal
coliforms |
856 |
1 |
0.12 |
0 |
1 |
0 |
0 |
|
Colour |
88 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Turbidity |
88 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Odour |
96 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Taste |
96 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Hydrogen
ion |
90 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Nitrate |
328 |
7 |
2.13 |
6 |
3 |
3 |
0 |
|
Nitrite |
88 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Aluminium |
94 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Iron |
154 |
0 |
0.00 |
0 |
0 |
0 |
1 |
|
Manganese |
88 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Lead |
18 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
PAH |
100 |
3 |
3.00 |
0 |
2 |
1 |
1 |
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Trihalomethanes |
41 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Total pesticides |
27 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Other pesticides |
496 |
0 |
0.00 |
0 |
0 |
0 |
0 |
|
Hydrocarbons |
18 |
1 |
5.56 |
0 |
1 |
1 |
0 |
|
Phosphorus |
170 |
1 |
0.59 |
0 |
1 |
1 |
0 |
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Potassium |
40 |
0 |
0.00 |
0 |
1 |
0 |
0 |
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All others |
974 |
0 |
0.00 |
0 |
0 |
0 |
0 |
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TOTAL |
4,806 |
17 |
0.35% |
6 |
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14 zones in 2000,
2001 and 2002 |
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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 | 77 |
1.0 µg/l |
0 |
| Bromate | 86 |
10.0 µg/l |
0 |
| 1,2 dichloroethane | 85 |
3.0 µg/l |
0 |
| Nitrite (ex-water treatment works) | 84 |
0.1 mg/l |
0 |
| Clostridium perfringens | 4 |
0/100 ml |
0 |
| Enterococci | 53 |
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 | 14 |
10.0 µg/l |
0 |
5.0 µg/l |
0 |
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| Arsenic | 14 |
50.0 µg/l |
0 |
10.0 µg/l |
0 |
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| Boron | 14 |
2.0 mg/l |
0 |
1.0 mg/l |
0 |
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| Copper | 14 |
3.0 mg/l |
0 |
2.0 mg/l |
0 |
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| Lead | 18 |
50.0 µg/l |
0 |
25.0 µg/l1 |
0 |
|||
10.0 mg/l2 |
0 |
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| Nickel | 14 |
50.0 µg/l |
0 |
20.0 µg/l |
0 |
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| Nitrite (at consumers' taps) | 88 |
0.1 mg/l |
0 |
0.5 mg/l |
0 |
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| PAH | 100 |
0.2 µg/l |
3 |
0.1 µg/l |
0 |
|||
| Tetrachloroethene | 41 |
30.0 µg/l |
|
10.0 µg/l
|
0
|
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| Trichloroethene | 41 |
10.0 µg/l |
Details of the new and revised standards, and the reasons for the revisions 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 progress with regulatory programmes of work | March 2002 |
| Review of plumbosolvency treatment and control programmes of work for lead | October 2002 |
| Audit of response to selected consumer complaints | October 2002 |
| Audit of analytical requirements for nitrate and nitrite | November 2002 |
| Audit trails of five test results | November 2002 |
| Inspection of one water treatment works and three service reservoirs | December 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 analytical requirements for nitrate and nitrite and plumbosolvency treatment for lead.
Incidents
The Inspectorate regarded the single event notified during 2002 by the Company as an incident. For further details on the classification of incidents, see chapter C "Events affecting Water Quality" in Part 3.
The incident has been assessed by the Inspectorate. It was of short duration and the Company has taken appropriate remedial action. A number of recommendations were made regarding sampling and procedures.
During the 2002 reporting period, assessment was also completed for one incident which occurred in 2001.
| Nature of incident | No. of incidents |
Assessment completed |
Area affected |
Population potentially affected |
| Microbiological contamination
of supplies |
1 |
Yes |
Horseheath (February) |
125 |
Enforcement Action
No enforcement action was considered for the Company as a result of the Inspectorate activities during 2002.
Undertakings and other Improvement Programmes
Water treatment works and service reservoirs
No improvement programmes were due for completion during 2002.
Distribution
The Company had completed its distribution system undertaking by December 2001.
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 programme is monitored by the Inspectorate and has been satisfactory.
