The water fittings regulations, bylaws in Scotland apply to all water fittings (both above and below ground) and water using appliances from the point where the mains water enters the property (usually the stop tap at the property boundary) to the point it is used by the consumer. The illustration below shows typical responsibility arrangements.
In addition to specific installation requirements set out in schedule 2, pipework needs to comply with regulation/byelaw 4(1).
The FAQs listed opposite include lots of useful information but some of the key points are:
All pipework, wherever it is installed, must be
Watertight and leak free link
Suitable link and appropriate for the environment in which it is installed link
Correctly labelled link
Protected from freezing and undue warming link
Below ground pipework must be
Installed at the correct depth link
Adequately separated from other utilities link
Ducted and insulated when entering a building link
Above ground pipework must be
Accessible for maintenance and replacement link
Supported link
Capable of being isolated and drained down with minimal waste link
Guidance to relevant requirements includes:
When designing a compliant plumbing system a number of factors need to be considered, including but not limited to:
Avoiding the risk of contamination or damage resulting from the environment in which the system is to be installed or due to the design itself.
The required and attainable supply pressure and other operational parameters
User expectations and whether these are achievable
Suitability of water fittings for use
Providing appropriate, adequate backflow protection.
Water efficiency
Limiting waste.
Useful sources of information include BS EN 806 and BS 8558
The supply pipe to a building should enter at a depth of 750 mm.
Pipework passing through walls and laid at depths of less than 750 mm, including any inside the building should be ducted. This is to prevent damage, and facilitate ease of replacement, the internal surface of the ducting should be smooth bore i.e. any ridging to be external only.
The pipework should be sealed using a method acceptable to the local water undertaker. This is to prevent ingress of gases and vermin. It should also be adequately insulated. Where pipework is installed below a suspended floor if there is an air vent the pipework should be ducted and insulated to the finished floor level.
The acceptability of the methods of protection for pipework is dependent on a number of location specific factors, such as the type and size of water fitting, the likely water supply and air temperatures as well as demand flow. Manufacturers usually provide information about the appropriate thickness and thermal conductivity in their technical specifications. BS EN ISO 12241 and BS 5422 are another source of useful information.
When installed in accordance with the manufacturer’s instructions insulation may delay but not prevent freezing. Examples of pipework entering a building at and below street level are given below.
Firstly, the pipe and fittings, including method of connection, should be suitable for below ground use and the environment in which they are to be installed. Joints should be kept to a minimum. Water fittings which are susceptible to permeation by hydrocarbons should not be laid in ground near installation storing or ground contaminated with petrol or oil unless protected.
Pipework should be laid at a depth of not less than 750 mm (to limit the effect of freezing and mechanical damage) and no greater than 1350 mm deep. It should be embedded in non-abrasive materials. In all circumstances where this cannot be achieved the consent of the local water undertakers must be obtained via notification.
Where the local water undertaker consents to pipework being laid at less than 750 mm it should be installed as deep as possible below ground level and protected against warming, freezing and mechanical damage (for example due to ground movement).
Examples of how to avoid below ground obstructions are given below. Please note the local water undertaker should be consulted before laying pipework over an obstruction.
Pipework should not be installed above ground level without the agreement of the local water undertaker.
Pipework should never be installed in a contaminated environment such as a sewer or cesspool.
Non-metallic (plastic) plumbing fittings are at risk of permeation by diesel or heating fuel, pesticides, insecticides and similar organic substances or fluids, so should never be installed where they could come into direct contact, including contact with soil contaminated with them.
Where this is unavoidable contact the local water undertaker for advice.
Joints on concealed pipework are likely to lose their integrity over time and therefore should only be considered where unavoidable.
To prevent waste there needs to be provision to access any joints or water fittings which require maintenance, such as backflow prevention devices, valves which control the flow and any other operational fitting.
All domestic hot and cold water system pipework concealed within walls should:
Be installed with a minimum number of joints. This is because joints are prone to a loss of integrity over time and therefore should only be considered where unavoidable.
Be installed in a chase/duct or void. Wrapping pipework in insulation is not an acceptable method of ducting or passing through a chimney is not an acceptable method of ducting.
With the agreement of the local water undertaker pipework may be installed alongside other services in a shared duct. An example of what may be considered as acceptable is shown below.
Be appropriately clipped to avoid water hammer and other stresses which would affect the integrity of the installation.
Be insulated with a suitable gap maintained between the cold water, hot water and any other heat source to prevent heat transfer or loss.
Not be embedded or come into contact with other materials such as plaster or cement.
Be accessible to enable inspection and replacement. Further information about accessibility can be found in BS 8558.
Below are images illustrating domestic hot and cold water systems concealed in a wall and a soil pipe duct.
Regulations & Byelaws which apply include but are not limited to:
Relevant guidance includes but is not limited to:
Uncontrolled if downloaded. This is informative, non-statutory guidance and intended for general guidance purposes only; it is subject to change.
Compliance with this information should not be relied upon as guaranteeing no enforcement action will be taken by water undertakers. Water Regs UK accepts no liability for loss, indirect or consequential loss arising from or in connection with this guidance document.
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