To be wholesome, water must comply with the water quality standards for the parameters set out in the Water Supply (Water Quality) Regulations 1989. In 2003, the Company carried out a total of 75,711 tests on samples of water leaving its 83 water treatment works, from its 137 service reservoirs and from consumers’ taps in its 108 water supply zones. Of these, 99.89% (75,629) complied with the standards set down in the Regulations. However, 0.11% (82) tests did not meet the standards. 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

A comparison of the Company’s performance in 2003 with data for 2002 and 2001, is given below. Differences over the last three years in the number of treatment works, and in the number of tests carried out on samples from treatment works, in which coliforms or faecal coliforms were detected, were not considered significant.

During 2003, the failures of the total coliform standard at four works were considered trivial, or unlikely to recur.

Two failures of the faecal coliform standard occurred at two works. These were regarded as trivial or unlikely to recur.

In 2003, 1,658 regulatory samples for Cryptosporidium were taken at six sites. Very low numbers of oocysts were detected in 39 samples from four sites. All results were well below the treatment standard and there were no reported outbreaks of cryptosporidiosis.

Water quality in service reservoirs

A comparison of the Company’s performance in 2003 with data for 2002 and 2001, is given below. There has been a significant decrease since 2002 in the number of service reservoirs in which total coliforms were detected. All other differences were not considered significant.

During 2003, total coliforms were detected at a single service reservoir. However, there were no failures of the total coliform or faecal coliform standard at any service reservoir.

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. A comparison is also given for parameters failing the standards in 2002 and 2001.

Parameter	Total number of tests	Tests not meeting standard		Number of failures covered by Undertakings	Number of zones not complying with the standards (number of zones in 2003 = 108)*
		No	%		2003	2002	2001
Coliforms	7,695	17	0.22	0	0	0	0
Faecal coliforms	7,695	2	0.03	0	2	4	7
Colour	544	0	0.00	0	0	0	0
Turbidity	1,640	0	0.00	0	0	0	1
Odour	544	0	0.00	0	0	0	0
Taste	544	0	0.00	0	0	0	0
Hydrogen ion	866	0	0.00	0	0	0	0
Nitrate	929	2	0.22	2	1	1	2
Nitrite	955	36	3.77	0	6	11	9
Aluminium	546	1	0.18	0	1	0	0
Iron	1,884	3	0.16	1	3	6	6
Manganese	543	0	0.00	0	0	0	0
Lead	454	1	0.22	0	1	0	1
PAH	271	8	2.95	0	5	7	3
Trihalomethanes	448	1	0.22	0	0	0	0
Total pesticides	342	0	0.00	0	0	0	0
Chlortoluron	223	1	0.45	0	1	0	1
Clopyralid	167	1	0.60	0	1	0	0
Isproturon	215	0	0.00	0	0	1	0
Other pesticides	3,885	0	0.00	0	0	0	0
Nickel	141	1	0.71	0	1	2	0
Oxidizability	122	1	0.82	0	1	0	1
Surfactants	119	0	0.00	0	0	0	1
All others	9,837	0	0.00	0	0	0	0
TOTAL	40,609	75	0.18

*110 zones in 2002 and in 2001

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.

There has been a reduction in the number of zones in which the nitrite standard was exceeded. This has been a result of operational changes to the Company’s distribution network which has improved blending in the affected areas.

The new Regulations

In 2003, the Company carried out monitoring for the six new parametric values set down in the new Water Supply (Water Quality) Regulations 2000. These Regulations came into force on 25 December 2003. The results are shown in the table below.

Parameter	Total number	New standard	Tests not meeting
	of tests		the new standard
Benzene	413	1.0µg/l	0
Bromate	424	10.0µg/l	1
1,2 dichloroethane	417	3.0µg/l	0
Nitrite (exwater treatment works)	587	0.1mg/l	0
Clostridium perfringens	418	0/100ml	1
Enterococci	428	0/100ml	0

Compliance data for 2003 have also been analysed against the revised standards and the results are shown in the following table.

Parameter	Total number of tests		Current Standard	Number of tests not meeting current standard	Revised Standard	Number of tests not meeting revised standard
Antimony		108	10.0µg/l	0	5.0µg/l	0
Arsenic		108	50.0µg/l	0	10.0µg/l	0
Boron		108	2.0mg/l	0	1.0mg/l	0
Copper		156	3.0mg/l	0	2.0mg/l	0
Lead		455	50.0µg/l	1	25.0µg/l	5
					10.0µg/l*	13
Nickel		141	50.0µg/l	1	20.0µg/l	1
Nitrite (at consumers’ taps)		955	0.1mg/l	36	0.5mg/l	0
PAH		271	0.2µg/l	8	0.1µg/l	0
Tetrachloroethene Trichloroethene		440 440	10.0µg/l 30.0µg/l	0 0	} 10.0µg/l	0
* Final standard not applicable until 2013

During 2003, the Company had a number of programmes of work in place to meet the new standards.

Details of the new and revised standards can be found in chapter J ‘New Regulations and Associated Programmes of Work’.

Audit and inspection

The Company was inspected or audited by the Inspectorate or its appointed consultants on a number of occasions during 2003. Where relevant, report summaries are available in the ‘Business and Technical’ section of the Inspectorate’s website under ‘Audit and Inspection’. Details of the subject areas audited or inspected are given in the following paragraphs:

Follow up of recommendations made during the 2002 inspections or in connection with water quality incidents

Steps have been taken to implement all of the recommendations arising from the 2002 audit and inspection process and from assessments of water quality incidents.

Audit of regulatory Cryptosporidium monitoring sites

The monitoring equipment at all regulatory sites visited during the year was found to be satisfactory.

Inspection of laboratory analysing for Cryptosporidium

The announced audit on the Company’s Cryptosporidium laboratory identified three regulatory breaches as well as a number of other minor deficiencies associated with the Standard Operating Protocol. The Company has taken the required remedial action to rectify the deficiencies identified.

Audit of progress with water treatment works improvement programmes

A desktop audit of three schemes associated with improvement programmes at water treatment works was carried out together with one site visit. The schemes were for bromate at Essendon treatment works; chlorinated solvents at Hart Lane/Crescent Road works; and for Cryptosporidium at Batchworth treatment works. Progress with all these schemes was considered satisfactory.

Review of distribution system undertaking

Progress with the programme of mains renovation set out in the Company’s continuing distribution system undertaking was found to be generally satisfactory. However, the Company is being required to take action on one minor matter concerning continued monitoring.

Audit of response to selected consumer complaints

A desktop audit of the Company’s response to 12 consumer complaints about drinking water quality was found to be satisfactory.

Audit trails of selected microbiological test results

Vertical audits were carried out on two test results selected at random for the period November 2002 to June 2003. The Company is being required to take action on deficiencies identified with transportation and storage of a sample.

Audit trails of selected nonmicrobiological test results

Vertical audits were carried out on eight test results selected at random for the period October 2002 to July 2003. The Company is being required to take action on deficiencies identified with the method of analysis for one parameter and also the associated instrument records. The Company and its laboratory were commended for the high standard of work and record keeping associated with the samples audited.

Audit of analytical requirements for nitrate and nitrite

Vertical audits were carried out of nitrate and/or nitrite samples taken in a single water supply zone over a sixmonth period to assess any changes in analytical requirements over time. The Company is being required to take action on deficiencies identified with the level of reporting for the nitrate results.

Audit of compliance with in situ rapid set epoxy lining guidelines

Compliance with the Code of Practice for in sit u rapid set epoxy lining was audited at two sites in January 2003. The Company is being required to take action on deficiencies identified over the extent of delegation to the contractor and with the post lining CCTV inspection.

Inspection of one water treatment works and three service reservoir sites

Inspections were carried out at Egham water treatment works, and at Onslow, Park Barn, Sunninghill No.1 & No.2 service reservoir sites. The operation and management of all the treatment works and service reservoirs were satisfactory. However, the Company is being required to take action on a number of minor deficiencies associated with manual water quality tests at Egham water treatment works, and operational arrangements at Onslow and Sunninghill service reservoir sites.

Audit of Company policies for the supervision of contractors working on the distribution system

A desktop audit found that the Company’s policy for the supervision of contractors working on the distribution system was satisfactory. The Company was commended for its supervisory arrangements.

Audit of Company policies for drilling and tapping activities on the distribution system

A desk top audit found that the Company’s policy for drilling and tapping activities on the distribution system was satisfactory.

Audit of plumbosolvency treatment and control programmes

Progress with the programme of work for plumbosolvency treatment and control measures for lead was found to be satisfactory.

Incidents

The Inspectorate regarded five events notified during 2003 as incidents. Further details of these incidents are given in the table below.

Three of the incidents were fully investigated and assessed by the Inspectorate during 2003. Each was of relatively short duration and, where applicable, the Company took appropriate action to protect public health. The Company was required to take action on a small number of deficiencies identified in respect of carrying out risk assessments and their sampling procedures. The remaining two incidents from 2003 are under consideration.

During 2003, investigations were also completed for one incident that occurred in 2002.

Nature of incident	Assessment completed during 2003
Discolouration of water supplies
Discolouration of supplies to 2,000 properties in the Ickenham area during February 2003, following work to reconfigure the distribution system after a burst main. The discoloured water was caused by water backfeeding through an open valve originally thought to be in the closed position.	Yes
Discolouration of supplies to 650 properties in the Therfield area (near Royston, Herts) during February 2003 following the drain down of Therfield water tower as a result of a telemetry cable failure.	No
Discolouration of supplies to 12,000 properties in Arkley and Barnet in May 2003 following the draindown of Arkley water tower as a result of a telemetry cable failure.	Yes
Discolouration of supplies to 7,500 properties in Great Dunmow in May 2003 following a trial shutdown of a trunk main. Supply of water with an unusual odour	Yes
Supply of water with an unusual odour to 6,000 properties in Ashford, Middlesex between February and April 2003. The odour resulted from mains rehabilitation work carried out on a ten inch trunk main.	No

Enforcement action

No enforcement action was considered for the Company as a result of the Inspectorate’s activities during 2003.

Improvement programmes

Water treatment works/service reservoirs

One undertaking associated with treatment works was due for completion during 2003. This was to install treatment at Slip End treatment works to remove nitrate. The undertaking was not completed by the due date of 25 December 2003 due to circumstances beyond the Company’s control. However, the undertaking was completed in February 2004.

Two Regulation 41 programmes of work to meet the new and revised standards set down in the new Water Supply (Water Quality) Regulations 2000 were due for completion in 2003. These were to install treatment at Hart Lane and Clay Lane treatment works to remove solvents. The programmes were completed on schedule.

Four statements of intent to reduce the risk of Cryptosporidium breaching the treatment standards were due for completion during 2003. The programmes at Batchworth and Egham treatment works were completed on schedule. Delays with the programmes at Mill End and West Hyde were not within the control of the Company. New completion dates have been agreed for 30 June 2004.

No other programmes of work at water treatment works and service reservoirs were due for completion during 2003.

Distribution

Progress for the distribution system undertaking was generally satisfactory. However, investigations showed that much less renovation was required than anticipated. During 2003, 39 km of mains were renovated. The Company is now required to renovate a further 237 km of mains by 31 December 2004.

Lead

The Company’s Regulation 41 programme of work to meet the revised standard for lead set down in the new Water Supply (Water Quality) Regulations 2000 has been progressing satisfactorily. Plumbosolvency treatment measures were installed at all sites specified in the programme by 25 December 2003.