Consultation on shake-up of water supply rules

Special rules on cryptosporidium will be removed from water supply regulations, according to a consultation issued by the Environment Department (DEFRA) on 29 December.1 Regulations will instead increase raw water monitoring and place more emphasis on risk-based management of water supplies.

The proposals address several developments which make the current regulations covering England and Wales obsolete: a recent change in emphasis in the management of water supplies, implementation of the EU water framework Directive and increasing evidence that strict rules on cryptosporidium are out of date.

The new approach to protecting supplies was advocated by the World Health Organization in its 2004 guidelines on drinking water quality (ENDS Report 359, p 59 ). Based on "water safety plans" for each catchment, it urges risk-based management of water supplies from source to consumer, with less emphasis on monitoring at the tap and in the supply system.

The water framework Directive will also affect UK drinking water legislation by repealing the 1975 Directive on surface waters intended for the abstraction of water supplies at the end of 2007. The framework Directive will also introduce requirements for monitoring ground and surface waters.

Tougher rules for risk assessment and monitoring of the parasite cryptosporidium are also needed. The rules were established in 2000 to enable companies to be prosecuted if they fail to protect consumers, but need to be revised to allow technologies other than filtration to be used to counter the organism (ENDS Report 383, pp 22-23 ).

The water industry is likely to welcome the consultation’s proposal to abolish 24-hour monitoring of cryptosporidium levels in water supplies with a high contamination risk.

Key changes proposed in the consultation are:

  • Quality monitoring at abstraction points: Article 7 of the framework Directive requires the chemical and microbiological quality of surface and groundwaters used for water supplies to be monitored. The aim is to prevent deterioration and improve quality to reduce the need to treat drinking water.

    The Environment Agency is responsible for implementing the Directive, but it has long relied on water company data on groundwater quality to flesh out its own limited monitoring.

    DEFRA argues that the most cost effective way to meet the new monitoring requirements is for water companies to monitor their water sources and share the data with the Agency. Although water quality monitoring at intakes and boreholes is regarded as best practice, the consultation notes that industry practices are "likely to be variable", necessitating a uniform approach.

    Water companies also need to monitor water quality to satisfy the water safety plan approach to meeting quality requirements. Such data are needed to inform companies’ risk assessments of the potential risks associated with each water source and to optimise the treatment process.

    The consultation paper proposes a statutory monitoring programme for raw waters. This would cover all priority substances except dichloromethane, which is not a risk because of its high volatility. A system of relaxations would prevent unnecessary repeated monitoring for contaminants which have been shown not to be a risk.

    The draft regulations also require each water supplier to monitor and analyse "such properties, elements, organisms and substances as it considers necessary" to achieve compliance.

  • Risk assessment:
    The existing requirement for suppliers to risk assess water sources for cryptosporidium contamination is in effect extended to cover all health risks.

    Cryptosporidium - a parasite which is resistant to chlorine disinfection and causes severe gastrointestinal illness - has posed particular problems for the industry over the past 20 years. In 2000, the Drinking Water Inspectorate made it compulsory for all water supplies to be risk assessed and for those at risk to be monitored. The measures have reduced waterborne outbreaks of the disease (ENDS Report 382, p 20 ).

    The intention now is to enable water suppliers "to undertake and document a single comprehensive risk assessment for each water supply chain embracing all hazards."

    DEFRA hopes to amend the regulations in the first half of 2007 and, apparently, apply the new risk assessment requirements in 2008, giving water companies about a year to update their existing risk assessments.

    Another change is that the DWI will no longer have to respond to suppliers’ risk assessments but will have the power to issue enforcement notices - or even prohibition notices - where treatment works are judged to pose a significant risk.

  • Cryptosporidium: The requirement for 24-hour monitoring under forensic conditions of cryptosporidium levels in treated supplies judged at risk of contamination would be abolished.

    The controversial "treatment limit" of one oocyst in ten litres of water which was designed to indicate an adequate filtration level would also be removed. The limit was intended to make it possible to prosecute companies who managed filtration systems poorly or who by-passed them to increase capacity.

    The abolition will please the industry as the measures proved expensive and difficult to implement. Furthermore, no prosecutions have been brought using the data collected.

    However, the regulations have improved knowledge of the organism’s levels in raw and treated waters. It also made companies improve treatment processes by installing extra filtration.

    But the abolition of the treatment limit should be welcomed because it was widely misunderstood by the industry and health professionals. It was sometimes interpreted as conferring an acceptability threshold for cryptosporidium contamination and incorrectly supposed to provide a degree of health protection.

    A recent example occurred in North Wales, where the issuing of a boil water notice appears to have been delayed because the cryptosporidium levels in treated supplies were much lower than the treatment limit (ENDS Report 383, pp 22-23 ).

    Another benefit of changing the legislation would be to open the way for ultra-violet or ozone disinfection to be used to counter the organism. The technologies are accepted in the US and cheaper and quicker to install than filtration.

    None of the changes would reduce protection against the organism, the proposals emphasise. Cryptosporidium would remain a major element in risk assessments and validation monitoring would still be required to show the organism is being removed effectively or that an effective dose of disinfection has been continuously applied.

    The offences of supplying unwholesome water and failing to observe treatment and monitoring requirements for cryptosporidium would also be abolished. Instead, a more general offence of failing to comply with regulatory requirements to make the necessary improvements in treatment processes would be extended to cover all risks.

  • Publicity for authorisations: The requirement to advertise in the local press would be removed where suppliers obtain authorisations to deviate from water quality standards for operational reasons. Instead the supplier will be able to advertise the change on its website, but must do so 14 days in advance.
  • Cost savings: The accompanying regulatory impact assessment estimates that the changes in raw water monitoring would have little impact on a firm’s costs. There may be savings of up to £634,000 per year or an increase of up to £139,000 on a programme currently estimated to cost around £1 million annually. But companies would probably continue with current practice where this exceeds the minimum requirements.

    Cryptosporidium monitoring in surface waters currently costs the industry up to £6.4 million per year, with a further £1.5 million for groundwater. Although monitoring will still be required for at-risk sites, the frequency may be reduced at low-risks sites and a relaxation of security requirements would lead to savings.

    The assessment puts the potential savings from cryptosporidium monitoring at up to £5.4 million and £1.3 million per year for surface and groundwaters respectively.

    At new works where extra treatment for cryptosporidium is required, the annual cost savings from using UV disinfection instead of membrane filtration would be up to £16.5 million.

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