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 541,902 tests on samples of water leaving its 101 water treatment works, from its 368 service reservoirs and from consumers’ taps in its 244 water supply zones. Of these, 99.91% (541,411) complied with the standards set down in the Regulations. However, 0.09% (491) tests did not meet the required water quality 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, failures of the total coliform standard at eight works were considered trivial, or unlikely to recur.

One failure of the faecal coliform standard occurred at one works. This was regarded as trivial.

In 2003, 5,309 regulatory samples for Cryptosporidium were taken at 15 sites. Very low numbers of oocysts were detected in 71 samples from ten 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. 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 or faecal coliforms were detected, were not considered significant.

During 2003, total coliforms were occasionally detected at a number of service reservoirs. However, there were no failures of the microbiological standards 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 = 244)*
		No	%		2003	2002	2001
Coliforms	20,790	242	1.16	0	2	3	2
Faecal coliforms	20,791	11	0.05	0	10	11	12
Colour	2,680	0	0.00	0	0	0	0
Turbidity	2,757	1	0.04	0	1	0	0
Odour	1,146	1	0.09	0	1	1	1
Taste	1,119	0	0.00	0	0	0	0
Hydrogen ion	2,680	0	0.00	0	0	0	0
Nitrate	3,079	11	0.36	0	5	4	3
Nitrite	3,655	140	3.83	0	39	31	24
Aluminium	2,888	3	0.10	0	3	2	1
Iron	9,356	17	0.18	1	17	4	9
Manganese	2,744	1	0.04	0	1	0	1
Lead	1,194	0	0.00	0	0	6	6
PAH	1,175	25	2.13	0	18	19	8
Trihalomethanes	1,052	0	0.00	0	0	0	0
Total pesticides	14,724	0	0.00	0	0	0	0
Atrazine	13,766	1	0.01	0	1	0	0
Chlortoluron	13,766	6	0.04	0	2	0	0
2,4D	8,316	4	0.05	0	4	0	0
Diuron	13,772	0	0.00	0	0	0	6
Other pesticides	283,251	0	0.00	0	0	0	0
Benzo 3.4 Pyrene	1,178	1	0.08	0	0	1	0
Phosphorus	253	0	0.00	0	0	0	1
Temperature	20,806	4	0.02	0	4	0	0
Zinc	1,099	0	0.00	0	0	1	0
All others	20,698	0	0.00	0	0	0	0
TOTAL	468,735	468	0.10
*244 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.

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	447	1.0µg/l	0
Bromate	447	10.0µg/l	0
1,2 dichloroethane	434	3.0µg/l	0
Nitrite (exwater treatment works)	460	0.1mg/l	0
Clostridium perfringens	109	0/100ml	0
Enterococci	1,163	0/100ml	4

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	276		10.0µg/l	0	5.0µg/l	2
Arsenic	339		50.0µg/l	0	10.0µg/l	0
Boron	302		2.0mg/l	0	1.0mg/l	0
Copper	1,092		3.0mg/l	0	2.0mg/l	0
Lead	1,194		50.0µg/l	0	25.0µg/l	3
					10.0µg/l*	39
Nickel	300		50.0µg/l	0	20.0µg/l	1
Nitrite (at consumers’ taps)		3,655	0.1mg/l	140	0.5mg/l	1
PAH		1,175	0.2µg/l	25	0.1µg/l	0
Tetrachloroethene Trichloroethene		1,059 1,050	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 and revised 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 most of the recommendations arising from the 2002 audit and inspection process and from assessments of water quality incidents. Action is to be completed in respect of three recommendations.

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 two regulatory breaches as well as one minor deficiency associated with the secondary concentration and the IMS of 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

An overview of progress with improvement programmes at water treatment works was carried out. This was found to be satisfactory.

Review of distribution system undertaking

Work for the programme of mains renovation set out in the Company’s distribution system undertaking, which is now complete, was found to be satisfactory.

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 of January 2003. The Company is being required to take action on deficiencies identified with follow up actions, records and methodology.

Audit trails of selected nonmicrobiological test results

Vertical audits were carried out on 13 test results selected at random for the period January 2002 to April 2003. The Company is being required to take action on deficiencies identified with scheduling and taking samples at regular intervals in respect of one parameter; the method of analysis in respect of six parameters; the record of analysis and the reporting of the results in respect of one sample; and the instrument records in respect of one parameter. The Inspectorate accepts that the Company has introduced new methods for several of the parameters audited. It has also introduced new procedures for reviewing control charts and identifying bias. The Inspectorate will follow these points up in the next audit.

Audit of analytical requirements for nitrate and nitrite

Vertical audits were carried out on 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 instrument records, analytical quality control and the corrective action taken when an out of control condition has occurred.

Inspection of seven water treatment works and four service reservoirs.

Inspections were carried out at Dorney/Taplow, Hambleden, Hampton, Orpington, Playhatch, Southfleet and Westerham Hill water treatment works; and at Betsoms Hill, Southfleet, Juniper Hill Tower and Yew Tree Tower service reservoir sites. The operation and management of the treatment works/service reservoirs were satisfactory. However, the Company is being required to take action on a number of minor deficiencies associated with maintenance identified at Dorney/Taplow works and Yew Tree Tower service reservoir; procedures for the return to supply of slow sand filters at Hampton works; the inspection and maintenance of boreholes at Orpington works; chemical delivery arrangements at all works; and sampling arrangements at Juniper Hill Tower service reservoir.

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.

Audit of procedures relating to mains operations by company and contract staff

Audits of Company procedures were found to be satisfactory. However, the Company is being required to take action on a number of minor deficiencies associated with operation and maintenance of the distribution system and the management of contract staff.

Incidents

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

Four 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 is being required to take action on a number of deficiencies identified in respect of accuracy of records, dissemination of information and operation of automatic shutdown on loss of disinfection. The remaining three incidents from 2003 are under consideration.

Nature of incident	Assessment completed during 2003
Discolouration of water supplies
Discolouration of supplies to 15,000 properties in Eltham, South East London in May 2003 following work to modify the distribution system. Advice to boil water	No
Microbiological contamination of supplies to 500 properties in the Deddington area of Oxfordshire in July 2003 as a result of an illegal cross connection to a private water supply Loss of disinfection	No
Failure of disinfection at Childrey Warren WTW, near Wantage, due to failure of the automatic changeover of a chlorine cylinder affected a population of 10,900 in the Wantage area of Oxfordshire in January 2003	Yes
In February 2003, a power blip caused the chlorine dosing equipment at Leckhampstead WTW to malfunction resulting in loss of disinfection of supplies to 4,400 people in the Newbury area. The works continued to supply water following the malfunction because of inadequacies in the automatic shutdown arrangements. Taste and odour	Yes
Diesel contamination of supplies to two properties in Aldbourne, near Swindon in January 2003	Yes
Solvent odour in supplies to eight flats in Sussex Close, London N19 in June 2003 as a result of contamination of a storage tank in the building caused by the use of an inappropriate paint in a confined space by a third party.	Yes
Chemical taste in supplies to 9,000 properties in Enfield due to elevated levels of polycyclic aromatic hydrocarbons, caused by changes to supply arrangements to alleviate low pressure problems.	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 a treatment works was due for completion during 2003. This was to install treatment at Sheeplands treatment works to remove nitrate. This undertaking was completed on schedule.

Three 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 Grimsbury treatment works to remove nitrate, and to amend operational procedures associated with treatment at Wilmington and Orpington treatment works to remove solvents. The programmes were completed on schedule.

One statement of intent to reduce the risk of Cryptosporidium breaching the treatment standard at Dorney/ Taplow treatment works was due for completion during 2003. The programme was completed on schedule.

No other improvement programmes associated with water treatment works and service reservoirs were due for completion during 2003.

Distribution

Work for the Company’s distribution system undertaking is now complete. No mains were renovated during 2003.

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.