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Volume 4
Chapter 8 Wholesome Water
8.1. A house meets the tolerable standard if it has an adequate piped supply of wholesome water available within the house.
Introduction
8.2. Every house should have a supply of wholesome water. An unwholesome water supply can cause significant and long-term health problems for occupants.
8.3. The tolerable standard is not the only statutory provision covering water quality in Scotland. Water supply Regulations govern the quality of supplies. We provide information on the Regulations in this chapter of guidance.
8.4. Local authorities have rarely used the wholesome water criterion of the tolerable standard as a basis for taking statutory action. Local and national house condition surveys have not routinely examined water quality. This may be because assessors have focused on more obvious problems in the house, such as dampness or instability. It may also reflect a lack of guidance on water quality issues for assessors or the specialist nature of testing wholesomeness.
8.5. Laboratory analysis is the only way to properly test whether water is wholesome. This is a specialist technical task, and professionals who work with the tolerable standard are unlikely to have the skills to carry it out. Some supplies will need testing, but assessors can draw on a wider range of indicators and information to identify cases where a supply is at greatest risk of not being wholesome. This chapter gives practical advice on how assessors should approach this element of the standard. It:
- explains how to identify houses that are most likely to have water supplies that may not meet the standard; and
- describes how to gather information needed to reach an informed decision.
Legislation
8.6. The wholesome water requirement has been part of the tolerable standard since it was introduced in 1969. The Housing (Scotland) Act 2006 did not change this.
Background
Types of Water Supply
8.7. There are two types of water supply in Scotland: public and private. The vast majority of houses in Scotland (accounting for about 97% of the population) are connected to the public supply. Private water supplies serve approximately 3% of the population of Scotland (around 150,000 people). Nearly every local authority in Scotland has houses connected to a private water supply. The highest proportions of houses with private supplies are in Highland, Argyll & Bute, Aberdeenshire, Perth & Kinross, Borders and Dumfries & Galloway.
'Wholesome' Water
8.8. Scottish Regulations set the standard for wholesomeness that public and private supplies must meet. The Regulations reflect a European Drinking Water Directive. They define wholesomeness with reference to the presence of chemicals and micro-organisms, and set out maximum levels and concentrations which water must comply with. There are separate Regulations for public and private water supplies. There are links to the Directive and the Regulations at the end of this chapter.
8.9. Neither the Scottish Office nor the Scottish Executive has in the past issued specific guidelines on the definition of 'wholesome water' for tolerable standard assessments. The European Directive and the Scottish Regulations now provide a clear frame of reference and an opportunity to establish a consistent approach. For the purpose of this guidance, assessors should use the definitions of wholesomeness set out in the Regulations. These definitions are technical and we have not listed them here, but you can access them via the website address at the end of this chapter.
Public and Private Supplies: Main Issues
8.10. The likelihood of water not being wholesome - and the causes - varies between public and private supplies. We discuss these in turn below.
Public supplies
8.11. Scottish Water monitors and controls the quality of this water and is responsible for ensuring that water is wholesome to the stopcock, located at the curtilage of the property, normally in the pavement just outside the house.
8.12. There are a number of water quality issues that can result from internal plumbing, including copper, lead and microbiological factors. But the main water quality issue with the public supply relates to lead. There is no significant lead in the public water supply; the lead problem is due to plumbing within houses and the impact this has on the lead content of water at the point of use.
8.13. There are clear health risks associated with high levels of lead in drinking water. But the presence of lead piping does not mean that the water is necessarily unwholesome, as the solubility of lead varies with the water chemistry. The Water Supply Regulations set a maximum permitted level of lead in drinking water. This is currently 25 micrograms per litre. Water with a lead content higher than this is unwholesome. This maximum limit will reduce to 10 micrograms per litre in 2013.
8.14. The main cause of high levels of lead in drinking water is lead pipes within the house. This problem happens more often in houses built before 1970 that have not had their pipes, tanks or fittings replaced. Local authorities have provided significant grant-funding to owners for lead pipe replacement. Where Scottish Water is aware that there is a problem with high lead levels in a particular area and where it is practical, it will take action to minimise the uptake of lead from pipes by introducing additives to the water during the treatment stage. This means that even where an assessor identifies lead pipes in a house, it does not necessarily follow that the water is unwholesome.
8.15. However, any lead pipes identified clearly represent a risk to the wholesomeness of the supply and every opportunity should be taken to reduce that risk and remove the lead pipes. Even where Scottish Water introduces additives, the lead standard can still be exceeded making the water unwholesome. The addition of chemicals to minimise the uptake of lead is clearly not sustainable and the only long term solution is the removal of lead pipes.
Private supplies
8.16. Private water supplies are more likely than public supplies to be unwholesome. Like public supplies, they are at risk of having a lead content that is above the acceptable level. They are much more likely than public supplies to have several other possible contaminants (such as chemicals and micro-organisms) that may affect the wholesomeness of the supply and which put at risk the health of those using the supply.
Making the assessment
8.17. The three-stage flow-chart below will help guide an assessor through the process of determining whether the water supply to a house is wholesome:
Assessing Wholesomeness: Stage by Stage Approach
8.18. Laboratory analysis is the only way to determine conclusively if a supply of water is wholesome at the point of use, normally the kitchen tap. But it is not practical, or necessary, for an assessor to arrange to test the water supply in every house he or she visits. Laboratory analysis is the final stage in this process. An assessor will normally need to arrange this only where a review of relevant information and a house visit suggest that the water supply may not be wholesome.
Stage One: Information Review
8.19. Scottish Water and local authorities have specific responsibilities around water quality and therefore hold information that might be useful for making assessments against the tolerable standard. A practical first step for an assessor before visiting the house is to check the available information about the quality of the water supply to the house. This could inform an assessor that a supply is unwholesome (for example where there has been a recent analysis of the water). Or an assessor may learn that there is a short-term problem affecting the house related to repair or improvement work. An assessor could take account of any short-term issue during the visit and this would not normally be a reason for a house to fail the tolerable standard.
8.20. An assessor will need to find out whether the water comes from a private supply or the public network. In many cases this will be clear from local knowledge. Where it is not, the occupier may be able to confirm the source. Local authority Environmental Health Departments hold a register of all properties in their area served by a private water supply.
8.21. Constructive working relationships and a good understanding of roles and responsibilities across organisations will be important to the smooth flow of information.
Public supplies
8.22. Compliance with the drinking water quality regulations is measured at the point of use in the house. If Scottish Water discovers the lead content in a sample of water taken from the point of use exceeds the maximum level permitted, it is required to inform the householder and provide them with advice on how to minimise their exposure to lead.
8.23. Scottish Water holds information on areas likely to have lead pipes and whether or not it has treated the supply to an area to reduce the tendency for lead pipes to contaminate the drinking water and make it unwholesome. Scottish Water will make this information available to local authorities 24. If an assessor considers that there may be other contaminants in the public supply, he/she should raise the issue with Scottish Water.
Private supplies
8.24. Each local authority may hold information relating to the quality of the water from private water supplies. Private supplies are categorised according to the number of people they supply:
- 'Type A' are larger supplies and provide water to houses with a total population of 50 or more people or provide on average 10 or more cubic metres of water a day. Local authorities have a duty to regularly monitor type A supplies within their area and, where a supply is not wholesome, take action to ensure the quality is improved.
- 'Type B' supplies provide water to houses with a total population of less than 50 people. The powers relating to type B supplies are more discretionary and local authorities can test any type B supply in their area to determine whether it is wholesome. Local authorities also have a duty to test type B supplies when the owner or consumer of such a supply asks them to do so.
8.25. Many professionals who work with the tolerable standard are local authority environmental health officers. Local authority environmental health services are likely to be the source of information about private water supplies. This should make the sharing of information straightforward in some discussions about private supplies.
Stage Two: House Visit
8.26. The next stage in the assessment process is the house visit. When at the house, an assessor should look for any evidence that suggests the water supply may not be wholesome. Assessors will normally rely on observable indicators to check the water; principally colour and odour. The assessor should turn on the tap and let it flow for around two minutes before examining the water. Unusual colour and odour could indicate that the water may not be wholesome, in which case the assessor would investigate further. Equally, some deviations from clear and odourless water do not necessarily indicate a problem. The assessor should not taste the water if there are concerns over its quality.
8.27. Some flats within tenement and multi-storey blocks receive their cold water supply via a tank located at the top of the building. Water supplied by a storage tank at the top of the building may smell or be discoloured and this may indicate a problem with the tank. An assessor should, where possible, check whether the tank is covered, vented and maintained.
Colour
8.28. Water can be naturally brownish in appearance depending on its source. Many Scottish supplies are derived from upland sources and the colour comes from naturally occurring organic compounds. Water may look white or cloudy; this is normally a result of dissolved air within the system and when left to stand will become clear. Neither of these necessarily indicates that the water is unwholesome.
Odour
8.29. Water will occasionally smell of chlorine; this is a normal effect of the treatment process and not an indicator that the water is not wholesome.
Lead pipes, tanks and fittings
8.30. Assessors should look at visible pipe work within the house to check whether the supply runs through lead pipes. However, the absence of visible lead pipes does not guarantee that the water is not contaminated with lead. Other sources of lead include lead water tanks, lead communication pipes (connecting the house to the stopcock at the curtilage of the property) and lead solder. Assessors should be aware that even in more modern properties with copper pipes, a risk still exists where the plumbing has been installed using lead solder.
8.31. Residents of the house may be a useful source of information on the quality of water. Relevant questions might include:
- have you noticed any significant changes in the quality of the water?;
- do you or your family regularly suffer from health problems such as sickness or diarrhoea?;
- is the water supply ever broken or at low pressure?;
- when was the tank last cleaned (for houses supplied by tanks at the top of the building)?; and
- (if private supply) do you know the location of the source of their supply?
8.32. The assessor should ask whether there are fluctuations in the supply. Low flow during dry periods will concentrate any contaminants and may take them above acceptable levels. If there appear to be such problems the assessor should arrange to revisit in a dry period.
8.33. If the assessor has any doubts about the quality of a private supply he/she should consider, where feasible, inspecting the source of the supply and the pipes connecting it to the house to check for the possibility of contamination from external sources such as animals or slurry overflow. But even where there is no visible evidence at the source indicating the supply is contaminated, the water may still be unwholesome.
Stage Three: Laboratory Analysis
8.34. If, at the end of stage two, the assessor is still uncertain about the wholesomeness of the water supply, he/she can request that the water is tested. If the test concludes that the water is not wholesome, then the house does not meet the tolerable standard.
Adequate supply
8.35. For a house to meet the tolerable standard, its water supply must be 'adequate' as well as wholesome. Assessors should consider whether the supply is adequate according to three factors: availability, pressure and continuity. Assessors should follow the first two of the three stages set out above ( i.e. information review and house visit).
Availability
8.36. Wholesome water should be available to the occupants of the house from at least one tap inside the house. This will normally be located at the sink, but a house will not fail the tolerable standard if it is available elsewhere in the house. As a point of good practice, assessors should tell the occupants of the house where the source of wholesome water is in the house if he/she thinks the occupants do not know.
Pressure
8.37. An assessor should visually examine the pressure of the water at the tap. Scottish Water is responsible for ensuring that public supplies meet the pressure specified in Regulations. In some cases, such as within flats in tenements or high-rise buildings, the pressure may appear slightly lower than normal due to the routing of supply through tanks. Significant pressure difficulties are most likely in private supplies, particularly during long periods of dry weather. A house will normally be below tolerable standard where an assessor observes very low pressure at the time of the visit and then confirms from the relevant body that this is an ongoing or regular problem rather than an isolated incident.
Continuity
8.38. Occasionally, maintenance or repair works will interrupt the public water supply. This is not relevant for the tolerable standard. Breaks in supply are most often an issue for private supplies. Dry periods in the summer can leave houses without water because the source has dried up. Where an assessor is aware that the supply is regularly interrupted for significant periods - for example several days at a time - the house is likely to be below the tolerable standard. Again, the assessor should discuss supply issues with the relevant body before finalising the assessment.
Immediate action
8.39. If an assessor suspects that the water supply to a house is unwholesome and poses an immediate danger to the health of the occupants of the house, he/she should inform the occupants immediately and arrange for the supply to be tested. This will normally only be on occasions where an assessor observes a significant unusual discolouration, or odour, or where he/she suspects there is a problem with a storage tank.
Enforcement
8.40. An assessor should be aware that there are two distinct routes available to local authorities for dealing with houses that are below tolerable standard on water quality. The first is under the Water (Scotland) Act 1980, using also the Private Water Supplies (Notices) (Scotland) Regulations 2006. The second is under the Housing (Scotland) Act 2006. Our Housing renewal areas & repair, improvement and demolition guidance explains how authorities can use enforcement powers to take action against below tolerable standard houses. Each local authority should decide which set of legislation it intends to use to deal with water quality issues and develop an appropriate procedure for this.
Further Information
8.41. The Drinking Water Quality Regulator ensures that Scottish Water achieves the specified standards for water quality. For more information on the public water supply, Scottish Water and the Drinking Water Quality Regulator, see: http://www.scottishwater.co.uk and http://www.dwqr.org.uk
8.42. For the European Directive see http://ec.europa.eu/environment/water/water-drink/index_en.html
8.43. The Water Supply (Water Quality) (Scotland) Regulations 2001 govern the quality of public water supplies in Scotland. Regulation 4 sets the standard for wholesomeness that the public supply must meet. See http://www.opsi.gov.uk/legislation/scotland/ssi2001/20010207.htm
8.44. The Private Water Supplies (Scotland) Regulations 2006 govern the quality of private water supplies in Scotland. Regulation 7 specifies the standard that such supplies should meet. The regulations distinguish between Type A and Type B supplies for the prescribed concentrations and values. See http://www.opsi.gov.uk/legislation/scotland/ssi2006/20060209.htm
8.45. Grants: if an assessor determines that a private water supply is unwholesome and below tolerable standard, he/she may wish to advise the owner or occupier that there are grants available through the local authority to make improvements to the water supply. More information on this is available through the local council, and at http://www.opsi.gov.uk/legislation/scotland/ssi2006/20060210.htm
8.46. Additional guidance on assessing water quality is available at http://www.scottishwater.co.uk and http://www.privatewatersupplies.gov.uk.
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