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Drinking Water Inspectorate: Information Letter 10/99 - 25 June 1999

To: Board Level Contacts in Water Service Companies and Water Companies in England and Wales

Dear Sir/Madam,

The Water Supply (Water Quality) (Amendment) Regulations 1999 : Cryptosporidium in Water Supplies

Purpose

1. The purpose of this letter is to advise water companies on the implementation of the Water Supply (Water Quality) (Amendment) Regulations 1999 ("the Regulations"), and the associated Guidance on Assessing Risk from Cryptosporidium Oocysts in Treated Water Supplies ("the Guidance") and Standard Operating Protocol for the Monitoring of Cryptosporidium in Water Supplies ("the Protocol").

2. A copy of the Regulations, Guidance and Protocol is attached. The Drinking Water Inspectorate will act for the Secretary of State in respect of all matters assigned to the Secretary of State in the Regulations.

The Regulations

3. The Regulations come into force on 30 June 1999. They require water companies to carry out risk assessments to establish whether there is a significant risk from Cryptosporidium oocysts in water supplied from each of their treatment works. Where it is established that there is such a risk, water companies must use a process for treating the water to ensure that the average number of Cryptosporidium oocysts is less than one per 10 litres of water. To verify compliance with this requirement water companies must ensure that the water leaving the relevant treatment works is continuously sampled and analysed daily for Cryptosporidium oocysts. The Regulations also require water companies to place the results of this monitoring on a publicly accessible record.

4. The Regulations provide that a water company which contravenes the requirement to ensure that the average number of Cryptosporidium oocysts is less than one per 10 litres of water, or which contravenes the monitoring (sampling and analysis) requirements, shall be guilty of an offence and liable to a fine on conviction. A water company will have a defence if it has taken all reasonable steps and exercised all due diligence to avoid the commission of the offence.

Risk Assessment

5. Water companies are required to carry out a risk assessment at each of their treatment works to establish whether there is a significant risk from Cryptosporidium oocysts in water supplied from the works. The attached Guidance provides advice to companies on the carrying out of these risk assessments.

6. The Regulations require water companies by 1 October 1999 to have completed their risk assessments and to have submitted their reports of the assessments to the Drinking Water Inspectorate, who will determine whether the risk assessments have been satisfactorily carried out. The reports should be in the format specified in Annex B of the Guidance. The Inspectorate will accept reports on disk or by e-mail provided they are clearly signed or authenticated on behalf of the water company. The Inspectorate will consider making an enforcement order in respect of any company which fails to submit its reports by 1 October 1999.

7. The Inspectorate will notify water companies by 31 October 1999 whether or not each risk assessment has been satisfactorily carried out. The Inspectorate intends to issue a single notice to each water company covering all the assessments that have been satisfactorily carried out and, when necessary, a further single notice to each water company covering all assessments that have not been satisfactorily carried out.

8. In respect of any assessments that have not been satisfactorily carried out, the notice from the Inspectorate will specify the reasons why and require the water company to carry out a further risk assessment and submit a report of that assessment by a specified date, which will normally be within one month of the date of the notice. The Inspectorate will notify water companies within one month of receiving the report of the further risk assessment whether the risk assessment has been satisfactorily carried out. The Inspectorate will consider making an enforcement order in respect of any company which fails to submit its report of the further risk assessment within the time specified above.

Programme for installation of sampling equipment or treatment

9. Where the Inspectorate is satisfied that the initial risk assessments have been satisfactorily carried out and the water companies have established that there is a significant risk from Cryptosporidium oocysts in the water supplied from one or more of their works, the notice issued by the Inspectorate will require each water company to submit within three months of the receipt of the notice a programme for the installation by the earliest practical date of the sampling equipment or additional treatment processes.

10. This programme should therefore include all the works initially assessed as having a significant risk and the latest date for its submission is 31 January 2000. The Inspectorate will consider making an enforcement order in respect of any company which fails to submit its programme by this date. Where installation is required at more than one works, the programme may be phased with the highest risk works first and in assessing the programme the Inspectorate will check the prioritisation of works and that the total programme is to the earliest practical timescale. The Inspectorate will inform water companies of its agreement or otherwise to the programme by 29 February 2000. If the Inspectorate judges a programme not to be the earliest practical or satisfactorily prioritised it will require the water company to submit a new programme within one month. The Inspectorate will consider making an enforcement order in respect of any company which fails to submit its new programme within this time. The Inspectorate expects each company to complete installation of the sampling equipment at its highest priority works by 31 March 2000 and then within two weekly intervals for the next priority works in sequence. The Inspectorate will take into account any difficulties that water companies may have in obtaining supplies of the sampling equipment in assessing the timescale of the programme.

11. Normally the programme will involve the installation of the continuous sampling equipment at each works at which a significant risk has been established. However a water company may install additional treatment or abandon the works in lieu of installation of the sampling equipment provided it agrees a timetable with the Inspectorate for the installation of the treatment or abandonment of the works and it adheres to that timetable. The Inspectorate may have supported a scheme for the installation of additional treatment in the context of the Periodic Review of Prices (AMP3) and, if so, the Inspectorate expects such a scheme to be completed as soon as practical.

12. Once the Inspectorate has assessed and is satisfied with the programme it will specify by notice to each water company, within one month of receiving the programme, the date from which it is required to comply with the monitoring (sampling and analysis) and treatment requirements of the Regulations for each works. Water companies may operate the sampling equipment and analyse the sample collection devices before that date as part of their operational monitoring.

13. In respect of any further risk assessment (see paragraph 8 above) which has been satisfactorily carried out and has established a significant risk, the latest date for submission of either a further programme or a revised programme is 31 March 2000. The Inspectorate will consider making an enforcement order in respect of any company that fails to submit its revised programme by this date.

Installation of continuous sampling equipment

14. Unless a water company has agreed with the Inspectorate an appropriate timetable for the installation of additional treatment or abandonment of the works, continuous sampling equipment must be installed at each point at which water leaves each works where a significant risk has been established. Part 1 of the Protocol, Sampling and Transportation of Samples, provides advice to water companies on the construction and installation of the sampling equipment. Annex 1 to this letter provides details of a complete commercially available sampling unit which meets the requirements of the Regulations and the Protocol. Water companies may construct their own sampling equipment provided it meets the requirements of the Regulations and the Protocol and it is approved by the Inspectorate. Annex 1 also provides details of suppliers of other approved items of equipment and consumables associated with the sampling equipment and the transport of samples. Annex 1 will be up-dated from time to time.

15. Water companies should note that where water leaves a treatment works at more that one point and the water is subjected to the same treatment processes, it is only necessary for the sampling equipment to be installed at one point. If there are situations where it is not clear whether sampling equipment needs to be installed at more than one point or there is a difficulty in deciding the location of a sampling point, the water company should discuss and agree with the Inspectorate the required sampling points and their locations.

16. All installed sampling equipment must be inspected by the Inspectorate prior to being used for monitoring under the Regulations. Companies must notify the Inspectorate when the equipment is ready for inspection. The notification must include a schematic diagram of the works showing the location of each sampling point. The Inspectorate will inspect the equipment as soon as possible so that water companies can meet the dates specified in the notices (see paragraph 12). Subsequently all sampling equipment may be subject to an annual inspection and in addition equipment may be subjected to unannounced inspections.

Sampling and transportation of samples

17. A continuous sample of water, consisting of at least 40 litres per hour on average during the sampling period, is required to be collected by the sampling device at each sampling point. Water companies are allowed up to one hour each day to change the sample collection device. Sampling is not required when no water is supplied from the sampling point. The sample collection device must be changed at least once each day, unless there are long periods when water is not supplied from the sampling point. Water companies must record the volume of water that has passed through each sample collection device and keep the record for at least one year.

18. At treatment works where water is supplied intermittently so that the volume of water passing through the sample collectiondevice is less than 200 litres per day, water companies are not required to change the sample collection device until the day on which the volume of water that has passed through the device equals or exceeds 200 litres.

19. Water companies are required to ensure that the sample is not contaminated when being taken and that the sample collection device, when removed from the sampling equipment is transported and maintained so that there is no material alteration in the state of the device that could affect the results of the subsequent analysis.

20. Comprehensive advice to water companies on the taking, handling, storage and transportation of samples is given in Part 1 of the Protocol, Sampling and Transportation of Samples.

21. Water companies are required to change the sample collection device immediately when there is a significant increase in the turbidity of water being supplied and sampled or any other indication that the number of Cryptosporidium oocysts in the water may have increased. The Inspectorate regards immediately as being as soon as practicable and in respect of turbidity water companies should follow the advice in paragraph 5.4.4 of the Third Report of the Group of Experts on Cryptosporidium in Water Supplies.

Analysis of the collection devices

22. The Regulations require that the analysis of the collection devices must be carried out at an approved laboratory using approved equipment and approved analytical systems and methods. Laboratories will have to be licensed to do the analysis by the Inspectorate. Part 2 of the Protocol, Laboratory and Analytical Procedures, specifies what is needed to obtain a licence and details the currently approved analytical systems and methods.

23. Any laboratory wishing to be licensed by the Inspectorate should notify the Inspectorate as soon as possible to arrange an inspection of the laboratory including inspection of its facilities, management systems, analytical systems, analytical methods, method validation, analytical quality control arrangements and arrangements for recording and reporting results. Any recommendations made by the Inspectorate must be satisfied and cleared before a licence will be given. All licensed laboratories may be subjected to an annual inspection and in addition they may be subjected to unannounced inspections at any time. Any licensed laboratory which relocates will be required, as a minimum, to revalidate its methods and to be inspected by the Inspectorate to retain its licence to carry out analysis for Cryptosporidium.

24. The Regulations require water companies to ensure that the sample collection device is analysed for Cryptosporidium oocysts within three days of its removal from the sampling equipment or in the situation covered by paragraph 21 above as quickly as possible and not longer than within one day of its removal from the sampling equipment. Water companies should note that a "day" is defined as the period of 24 hours commencing immediately after midnight.

25. Following the analysis of the collection device, the supervisor of the analysis must certify, within the three days or one day, as the case may be, allowed for the analysis, the results of the analysis and set out the average number of Cryptosporidium oocysts per 10 litres of water sampled calculated from the number of oocysts in the sample collection device. Water companies should note that a copy of this certificate will be admissible as evidence in any proceedings brought against a water company for the offence of supplying water from a treatment works containing an average of one or more Cryptosporidium oocysts in 10 litres of water. The certificate may include more than one result provided all relevant details for each result are given and the specified time limits are met.

Reporting of results

26. The Protocol requires that all results of analysis under the Regulations must be reported by the laboratory to the water company within one day. Any result which indicates that the water supplied contained an average of one or more Cryptosporidium oocysts in 10 litres of water must be reported by the laboratory by telephone and confirmed by facsimile (or e-mail) copy of the draft certificate of analysis to the designated water company person as soon as practical after the completion of the analysis. When this situation applies the designated person in the water company must inform by telephone, and confirm by facsimile (or e-mail) copy of the certificate of analysis to a designated person in the Inspectorate as soon as practical after it receives the information from the laboratory in accordance within normal incident notification procedures.

27. A monthly summary of all results from each sampling point must be sent to the Inspectorate within 15 days of the end of each calendar month. Part 2 of the Protocol specifies the information these summaries must contain. The Inspectorate will issue details for the electronic submission of these data in due course. Water companies should also note that the results of analyses must be placed on the public record within 28 days of the day on which the water company receives the results.

Action on results

28. Water companies should agree procedures with local authorities and health authorities for notifying them of the results of analyses made under these Regulations. As a minimum the Inspectorate recommends that water companies notify the relevant authorities on each occasion that the average number of Cryptosporidium oocysts in a sample is one or more in 10 litres of water. Water companies should also discuss and agree with local authorities and health authorities any action that may need to be taken in these circumstances. Any action will depend on the local circumstances, including history of the water supply and the exposure of the population. The Inspectorate is considering with its medical advisers whether further advice to that given in paragraph 29 below is warranted.

29. Water companies and these authorities should note that the Inspectorate has received the following medical advice:

We do not live in a sterile environment. Our bodies are at constant risk of encountering and being invaded by a variety of viruses, bacteria and parasites. Our immune systems have evolved to overcome such challenges through the co-ordinated action of certain white cells and proteins. There is a built-in immunological memory which ensures that there is rapid and effective reaction to any organisms which have been encountered in the past.

A small number of Cryptosporidium oocysts below the level in these Regulations is easily dealt with by the normal immune system because in a healthy person the immune system is primed to respond rapidly. However the situation for the immunocompromised is very different. See attached draft advice in Annex 2.

Other laboratory and analytical matters

30. All laboratories licensed by the Inspectorate to carry out analysis for Cryptosporidium under these Regulations must participate in an approved scheme for the external assessment of their performance in analysing for Cryptosporidium. Part 4 of the Protocol, Requirements for Interlaboratory Proficiency Schemes, provides details of the operation of a Scheme and the laboratories that are eligible for operating a Scheme.

31. The Inspectorate expects that there will be further developments in sampling and analytical procedures for Cryptosporidium which will improve the efficiency of the monitoring process. It is necessary to have a system for testing and approval of such developments because the Regulations require approval by the Inspectorate before they can be used. Part 3 of the Protocol, Validation of New Methods or parts of Methods for Sampling and Analysis, sets out what needs to be done, who needs to do it and criteria that have to be satisfied before approval can be considered by the Inspectorate.

32. Occasionally the Inspectorate may wish to remove without prior notice samples at any stage of the sampling or analysis for independent analysis. The results of such analysis will be reported by the laboratory carrying out the analysis to the Inspectorate and by the Inspectorate to the relevant water company within the timescales set out in paragraph 26 above.

Review of risk assessments

33. Where a water undertaker has carried out a risk assessment which has established a significant risk and has installed or is installing continuous sampling equipment , it may at any time carry out a further risk assessment to establish whether there continues to be a significant risk and submit a report of the assessment to the Inspectorate. Clearly the Inspectorate would only expect a water company to carry out a further risk assessment if there was a material change in circumstances or new information. If that assessment establishes that there is no significant risk and the Inspectorate is satisfied that the risk assessment has been satisfactorily carried out, the Inspectorate within one month of the receipt of the assessment will notify the water company that it need no longer monitor for Cryptosporidium oocysts under the Regulations.

34. Where a water company has established that there is no significant risk, the Inspectorate may by notice require a water company to carry out a further risk assessment by a specified date, normally within three months of the notice. The Inspectorate will follow this procedure when a water company notifies the Inspectorate, as it is required to do under the Regulations, of any factors that it becomes aware of which make it likely that there is a significant risk. The Inspectorate will follow this procedure to initiate a periodic review of all assessments that showed no significant risk. It is unlikely that such a periodic review will be carried out within three years.

Revisions to this Information Letter, the Guidance and the Protocol

35. The Information Letter, Guidance and Protocol are on the Inspectorate's Website, http:/www.dwi.detr.gov.uk. They will be reviewed and revised periodically in the light of experience and new developments. Water companies will be informed by a new Information Letter which will include any revised version of the Guidance or the Protocol and these will be immediately put on the Website. The versions of the Information Letter, Guidance and Protocol on the Website will be the official documents to be used for regulatory purposes.

36. Water companies should inform the Inspectorate if they have constructive suggestions for improving the Information Letter, the Guidance and the Protocol.

Submission of information to the Inspectorate

37. The various submissions required by this Information Letter and enquiries on it should be sent to the following designated persons:

Enquiries

38. Any general enquiries about this letter should be sent to Owen Hydes, Deputy Chief Inspector, Zone 2/E4, telephone 020 7944 5960. specific enquiries should be addressed to the relevant person mentioned in paragraph 37 above.

39. Please acknowledge receipt of this letter using the attached slip and reply paid envelope.

40. Copies of this letter and the attachments are being sent to Pamela Taylor, Chief Executive, Water UK; Bob Dinwiddy, Water Supply and Regulation Division, Department of the Environment, Transport and Regions; Bob Macey, Environment Division, Welsh Office; Tim Hooton, Scottish Office Agriculture, Environment and Fisheries Department; Randal Scott, Drinking Water Inspectorate for Northern Ireland, Rowena Tye, Office of Water Services; and Ailsa Wight, Department of Health. Copies of the letter only are being sent to each local authority and health authority in England and Wales.

Yours faithfully


Michael Rouse
Chief Inspector
Drinking Water Inspectorate

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Updated 11 July 2001
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