Events Affecting Water Quality
Describing the Inspectorate’s role in respect of investigation of events, which have affected drinking water quality adversely, and any consequent prosecutions of water companies where water has been supplied that has been deemed unfit for human consumption.
Water Quality Events
The Water Undertakers (Information) Direction 1998 (the "Information Direction") specifies information that companies must provide to the Inspectorate on their water supply systems, water quality and lead in their water supplies, and in respect of incidents and emergencies likely to affect or be related to water quality.
The conditions under which companies are to notify the Secretary of State are detailed in the Information Direction page of this DWI website. DWI Information Letter 13/99, also available on the website, gives further guidance. Companies are required to notify the Inspectorate as soon as maybe of events that, in their opinion, meet any of the criteria prescribed in the Information Direction. Notified events must be confirmed in writing within 72 hours and a full report provided within one month. Companies are also encouraged to notify the Inspectorate informally of events not meeting the prescribed criteria but potentially affecting water quality or consumers.
As a result of differences between companies in the interpretation of the notification requirements, and inconsistency in informal reporting, the Inspectorate set out new guidelines in Information Letter 13/99 to clarify the requirements. The Inspectorate may be notified of an occurrence as a potential incident which does then not develop; conversely an occurrence which does not appear to constitute a notifiable event may be informally notified to the Inspectorate and subsequently develop into an incident. Thus, the following terms have now been adopted as defined below and are used in this report.
Event
Any occurrence which by its nature is required to be notified under the Direction. It is not possible to provide an exhaustive list of situations that are regarded as events. Water companies have to use their judgement in any particular set of circumstances.Incident
A sub-set of events defined by the Inspectorate to include:
- a non trivial and unexpected breach of Part II of the Regulations; or
- a breach of Part VI of the Regulations; or
- an unusual deterioration in water quality; or
- a significant risk to the health of consumers; or
- significant consumer perceived adverse water quality changes.
Non incidents
All other event notifications not classified as incidents.The Assessment of Incidents flow diagram illustrates the process and timescale in which incidents and non-incidents are managed by Water Companies and the DWI respectively.
One hundred and thirty nine incidents, brief descriptions of which are given in the relevant individual company sections, which affected the quality of water supplied to approximately 2.6 million consumers, were notified to the Inspectorate in 2000. The period during which water quality was actually or potentially compromised ranged from a few hours to several days. A breakdown and a four-year comparison of categories of these incidents are graphically represented in the Breakdown of Incidents Reported.
Breakdown of Incidents Reported
In addition to the 139 incidents, a further 290 events were notified. A four-year comparison of the number of events (incidents and non-incidents) notified is illustrated in the Events Notified graph. It should be noted that following completion of assessment by the Inspectorate, events notified as incidents might be re-classified as non-incidents, and vice versa.
Events Notified
All phases of incident assessment should be completed by the targeted timeframe as detailed in the Assessment of Incidents flow diagram. The total number of assessments completed, as at 31 March 2001 is given in the Event Assessments Completed table.
Event Assessments Completed
Incidents Notified in 2000:
139
Non-Incidents Notified in 2000:
290
Total Number of Events in 2000
429
2000 Events Assessed:
392
No action required:
335
Recommendations:
53
Enforcement Action:
3
Caution:
1
Prosecutions:
0
Pre - 2000 Events Assessed in 2000:
54
No action required:
8
Recommendations:
32
Enforcement Action:
0
Caution:
7
Prosecutions:
7
Total Number of Assessments Completed in 2000
446
2000 Assessments Outstanding:
37
Pre - 2000 Assessments Outstanding:
21
Total Number of Assessments Outstanding
58
Enforcement Action
The Inspectorate's purpose in assessing incidents is to secure as far as possible that incidents are avoided in future. When assessing an incident, it must consider whether any enforceable regulation has been breached, whether the breach is likely to happen again, and whether water was supplied that was unfit for human consumption.
As a result of three incident assessments completed in 2000, enforcement action is, or has been, under consideration for two companies in respect of breaches of regulations.
Prosecutions
When considering whether water has been supplied that was unfit for human consumption, the Inspectorate takes into account many factors including data on the quality of water supplied during the incident and information on whether any illness or discomfort arose amongst consumers as a result of ingestion of or contact with the water.
Prosecution proceedings remain under consideration for 30 incidents (17 reported in 2000 and 13 reported in 1998 or 1999) for which assessments have not yet been completed. If prosecution proceedings are to be initiated, the assessment of an incident will not be completed until the prosecution proceedings have been concluded, whether or not the prosecution is successful. Of the 30 outstanding, one case (Yorkshire Water) is currently pending court.
The Inspectorate initiated successful prosecutions against three water companies during 2000 relating to seven incidents occurring in 1998 and 1999.
North West Water was prosecuted in October 2000 on account of two incidents occurring in 1998 and 1999.
Discoloured water was supplied following planned work on the distribution system in the Wallasey area. The Company was fined £12,000, with £10,471 costs. Three other cases involving the supply of discoloured water to: St Helens (September 1998); Eccles (October 1998); and Rainford (February 1999) were taken into consideration by the Court.
Water supplies were contaminated with hydrocarbons following recycling of contaminated surface water to the wash water recovery system at Hurleston treatment works. The Company was fined £20,000, with £7,100 costs. Two other cases: Cheadle Hulme (October 1998); and the Macclesfield (January 1999) taken into consideration by the Court.
Yorkshire Water was prosecuted in December 2000 on account of four discolouration incidents occurring in 1998.
Discoloured water was supplied following planned work on the distribution system in the Sheepscar area of Leeds. The discolouration arose due to the disturbance of sediment caused by changes in flow within the mains. The Company was fined £21,000.
Discoloured water was supplied following overnight tests carried out by the Company on the distribution system in the Drighlington area. The Company was fined £28,000.
Discolouration of supplies followed the return to supply of Idle Hill service reservoir that had been out of supply for several years. Consumers in the Idle Hill area of Bradford were affected. The Company was fined £20,000.
Discoloured water was supplied following operational problems at Marton treatment works following planned work on the raw water main. The incident affected consumers in Marton cum Grafton and Boroughbridge The Company was fined £50,000.
The Company pleaded not guilty to charges relating to three other incidents that occurred in 1997 and 1998 but the trial judge ordered that these should remain on the file. Combined costs of £125,599 were awarded in relation to the four prosecutions.
Mid Kent Water was prosecuted on account of an incident which occurred in 1998. Discoloured water was supplied to consumers in the Hadlow area. The incident occurred as a result of poor supervision of a mains refurbishing scheme being carried out as part of the Company’s distribution system undertaking. The Company was fined £12,000, with £43,077 costs.
Formal Cautions
In some circumstances evidence may be available to demonstrate that water unfit for human consumption was supplied, but the quality of the Company’s response or other mitigating circumstances mean that prosecution may not be the most appropriate approach. In such cases the Inspectorate may issue a formal Caution to the Company involved, which remains on file.
In 2000 the Inspectorate issued formal cautions to four companies relating to seven incidents which occurred between 1997 and 2000.
Sutton and East Surrey Water was formally cautioned in April 2000 following an incident occurring in 1997. Discoloured (chalky) water was supplied to parts of Morden following planned work on the distribution system.
North West Water was cautioned in May 2000 following an incident occurring in 1999. Supplies were contaminated with diesel oil during a planned operation which was affected by adverse weather conditions.
Wessex Water was cautioned in May 2000 following an incident in 1999. Discoloured water was supplied to Market Lavington following operational problems at the water treatment works.
North West Water was cautioned in June 2000 following an incident occurring in 1998. Supplies to Whitworth were contaminated with PAHs during planned refurbishment of the local distribution system.
Three Valleys Water was cautioned in August 2000 following an incident occurring in 2000. Supplies to parts of rural Essex received discoloured water following planned valving operations in the area.
North West Water was cautioned in August 2000 following an incident occurring in 1998. Parts of Rochdale received discoloured water following repairs to a burst main.
North West Water was cautioned in September 2000 following an incident occurring in 1998. Discoloured water was supplied to the Ormskirk area after a service reservoir was allowed to empty.
The Water Company Incidents and Prosecutions table gives the number of prosecutions, which have taken place following DWI's investigation of incidents, which occurred from, 1997 to 2000. It also shows the number of cases pending court and the number of incidents that are still under consideration as at 31 March 2001. In studying the numbers it is important to take into account the following:
- The number of incidents occurring can be expected to be proportional to the size of the water company and particularly the length of the distribution system
- Most of the incidents are minor events affecting a small number of consumers
- Many of the incidents occur for reasons outside the control of water companies. e.g. A burst main caused by ground movement.
- Prosecution cases take at least a year to get to Court so they do not necessarily reflect the position today.
Water Company Incidents and Prosecutions
Water Company Incidents and Prosecutions 1997 - 2000
Water Company
Population Supplied
KM of Mains
No of Incidents notified in year
Prosecutions (Cautions)Completed between 1997 and 2000
Cases Pending Court at 31/03/01
Incidents still under investigation as at 31/03/01
1997
1998
1999
2000
1997
1998
1999
2000
Anglian 4,000,000
34,641
9
13
16
18
2
3
Bournemouth and W Hants
430,000
2,800
0
1
0
0
Dee Valley
257,100
1,913
1
1
1
0
Dwr Cymru
2,800,000
24,900
13
10
9
11
3
3
5
Essex & Suffolk
1,700,000
8,406
4
2
5
4
2
Folkestone & Dover
160,000
1,068
0
0
0
2
Hartlepool
90,000
481
0
0
0
1
Mid Kent
563,300
4,220
0
2
4
0
1
2
North Surrey
473,000
2,492
1
0
0
0
North West
6,800,000
40,000
12
34
27
16
1
2
3(4)
3
Northumbrian
2,600,000
16,515
14
13
12
11
1
(1)
1
Portsmouth
647,000
3,200
1
1
4
1
2
Severn Trent
7,200,000
41,000
5
9
20
19
1
1
4
South East
1,358000
9,078
3
3
4
7
1
2
South Staffs
1,200,000
5,725
2
0
1
3
1
South West
1,500,000
15,000
8
3
4
7
1*
2
1
Southern
2,250,000
13,214
1
2
2
3
Sutton & East Surrey
630,000
3,300
2
1
2
0
1
(1)
Tendering
140,000
915
1
1
1
0
Thames
7,600,000
31,000
4
9
13
7
1
6
Three Valleys
2,300,000
11,000
2
1
10
9
(1)
Wessex
1,200,000
10,800
4
3
4
4
(1)
(1)
York
174,300
962
0
0
1
-
Yorkshire
4,500,000
29,000
15
15
26
16
1(1)
4
1
18
TOTAL
51,907,700
320,218
102
124
166
139
4 (0)
9 (2)
10 (0)
8(8)
1
48
Assessment of Incidents Flow Diagram
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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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