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Drinking water 2010 July 2011 Private Water Supplies – What it all means to me? Phil Smart Laura Moss Drinking Water Inspectorate
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Drinking water 2010 July 2011 Chief Inspectors Report on Private water supplies (CIR) DWI – Who are we? Technical advisers Assist LA implementing the Regulation for Private Water Supplies. Further information in Chief Inspectors Report (CIR)
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Drinking water 2010 July 2011 Private Water Supplies for England and Wales 2011. All supplies reported.
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Drinking water 2010 July 2011 North East England
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Drinking water 2010 July 2011 North West England
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Drinking water 2010 July 2011 Microbiological compliance
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Drinking water 2010 July 2011 Private water supplies Overview of sample failures 2011 Food Premises AccommodationPublic buildings Milking Parlours ENGLAND Detecting E.Coli or Enterococci 5.3%11.8%5%11.3%
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Drinking water 2010 July 2011 Change of approach for PWS New private water supply Regulations were introduced 2010
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Drinking water 2010 July 2011 Change of approach for PWS Local Authorities need to undertake a risk assessment In 2012 a new risk assessment tool was developed with LA’s to address; – Broader range of hazards and risk ratings – Mitigation – Treatment systems – Distribution systems
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Drinking water 2010 July 2011 Change of approach for PWS Duty of Local Authorities to improve supply where risks identified. – With Regulation18 Notices if actual or potential danger to human health – With Section 80 (Water Industry Act 1991) Unwholesome but not a potential danger too human health or insufficient supply Local authorities will revisit based on the risk to the supply.
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Drinking water 2010 July 2011 LAs will be looking for: Any water quality hazards that present a risk evidence that risks are being controlled. evidence that the supply is being adequately operated and maintained (an assessment of confidence) contingency arrangements and emergency plans What are the LA’s looking for when undertaking a Risk Assessment?
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Drinking water 2010 July 2011 How can you show you are in control of the risks? Self assessment; ―Provide LAs with evidence that risks are being control (mitigated) ―Evidence of maintenance work ―Evidence of improvements made ―Checks and records available and well maintained ―Knowledge of the supply - location of the source, tanks pipes ―An understanding of how the treatment system works and it’s limitation.
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Drinking water 2010 July 2011 Simple Supply plan
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Drinking water 2010 July 2011 Supply plan
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Drinking water 2010 July 2011 Simple questions – Self assessment. Do you know where the source is? Do you have control over the source? Is the source protected from livestock? Is there a protective chamber around the source? Is the chamber watertight and vermin proof?
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Drinking water 2010 July 2011 Do you have control of the source?
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Drinking water 2010 July 2011 Protection of Spring source
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Drinking water 2010 July 2011 Ingress?
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Drinking water 2010 July 2011 Borehole
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Drinking water 2010 July 2011 Is the source protected?
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Drinking water 2010 July 2011 Protecting the source Protection of the Borehole head works from ingress
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Drinking water 2010 July 2011 Protecting the source
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Drinking water 2010 July 2011 Pest proofing.
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Drinking water 2010 July 2011 Maintenance
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Drinking water 2010 July 2011 Sediment from the reservoir
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Drinking water 2010 July 2011 Confidence in management is; – Understanding how it works – Understanding its limitations – Understanding when it is not working and when information need to be shared. Treatment systems
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Drinking water 2010 July 2011 Hygienic systems of works
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Drinking water 2010 July 2011 Example of managing a treatment system on a private supply The borehole PWS - 23 domestic dwellings (19 rented). Previously failed for E. coli Supply was improved - chlorine disinfection Satisfactory sample! Job done? Does one satisfactory sample make a supply safe? Can a risk assessment make it safe? Was there any ongoing management? Fit and forget?
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Drinking water 2010 July 2011 Poor management of treatment system Dosing unit disconnected when errors arose, – with no notification of users – no provision for alternative treatment (i.e. no back up) The Regulation 18 Notice included; – management procedures to be specified – Trigger and action levels to be specified (alarms advisable)
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Drinking water 2010 July 2011 Adequate filters for source water? Validated? Effective disinfection? Maintenance and records
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Drinking water 2010 July 2011 Treatment system schematic Storage tank 10 micron filter 1 micron filter Turbidity monitor and alarm Ultra Violet treatment system Shut down device Storage tankHouses Ultra Violet treatment system
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Drinking water 2010 July 2011 Simple records and documentation Name and make of equipment Certification/ validation/verification paperwork Manufacturers instructions Your instructions Installation date Maintenance - what you do? Checks and records Evidence that equipment WRAS approved or from DWI list of traditionally used products. Plan of treatment ( schematic)
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Drinking water 2010 July 2011 Final Summary Keeping good records helps show how well you manage your supply Information provided demonstrates how well you understand your supply Confidence in management DWI Guidance - Chief Inspector’s Report, Technical notes, treatment systems, specific guidance on www.dwi.defra.gov.uk www.dwi.defra.gov.uk Chief Inspector’s Report – provides case study examples and annual data
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