Water world
Changes to Part G regulations on water supply in buildings have been
delayed until April – which gives readers more time to digest their
implications. Brian Whorlow analyses what’s in store
Water quality user controls (usually consisting of a two-position lever,
As rainwater harvesting systems and recycled ‘grey’ where the first position provides the user with a low
waste water systems grow in popularity, it is only flow option), shower heads and tap nozzles with an
sensible that the new requirement G1 of Part G of aerating design (which deliver an air/water mixture)
the Building Regulations should clarify that only giving the impression of a plentiful supply. Where
‘wholesome’ water (that is, safe to drink) is supplied high-use water fittings are required by the customer,
to washbasin, bidet, shower or bath used for washing, this can be offset by the use of recycled rainwater or
and any sink used for food preparation. treated grey waste water.
Recycled rainwater or treated grey waste water will The requirements will mean that ‘contract quality’
now be allowed only as an alternative supply for WCs, brassware will no longer be adequate in basic housing
urinals (sanitary conveniences), washing machines projects, and specifiers will need to add terminal flow
and irrigation systems. restrictors to projects or select alternative reduced
The new Part G classifies water in simplistic terms as flow taps in order to meet the regulations. The new
being ‘wholesome’ or ‘non-wholesome’. However, as the guidance to support requirement G2 states that a
Building Regulations will now encompass water safety record and statement about the water efficiency of the
aspects, it might seem odd to some people that there is installed sanitary appliances should be provided for the
no mention of the need to ensure that artificially softened householder, so that users are encouraged to maintain
water does not supply sink taps used for culinary purposes, the performance of the installation.
drinking fountains, ice machines and other terminals The water conservation legislation is only applicable
where the water is used specifically for ingestion. to new dwellings or existing buildings where one or
more dwellings are created by a change of use (such as
Conservation the conversion of a warehouse into apartments). In a
A new requirement to be introduced will impose a situation applicable to an existing dwelling, where the
maximum average daily demand of 125 litres per person sanitary appliances and the domestic water services are
for new dwellings based on an assessment method. being totally replaced, there is no legal requirement
This will require the careful selection of fittings with to apply water conservation measures, even though
emphasis being placed on aspects such as: the work will need to comply with all other current
• Taps and mixers which incorporate water-saving Building Regulations and Water Regulations.
features;
• Baths which do not have excessive water volumes; Bathroom safety
and The provision of thermostatic protection for baths
• Washing machines and dishwashers having a good is only required in new dwellings, or for existing
water-efficiency rating. buildings where one or more dwellings are created by
The performance of the proposed water fittings a change of use.
will need to be documented on a water calculator Therefore, where an existing bathroom in a house
that can be downloaded from the Department for is being totally stripped-out and replaced with new
Communities and Local Government (CLG) website. sanitary appliances, there is no legal requirement for
New Part G This is essentially a form designed to assess whether the replacement bath to be provided with thermostatic
classifies water
the installation meets the target water consumption protection.
value. The original calculation process, issued in Maintenance, or lack of it, could become an issue. In a
in simplistic
May, has been superseded by a version released in domestic application, thermostatic mixing valves should
terms as September. be inspected and tested annually, but standard plastic
being either
The water calculator will steer industry towards bath panels are not designed for regular removal.
the selection of terminal fittings that have one, or a Education will also affect the maintenance aspect,
wholesome
combination, of water-saving features such as flow as householders may not be aware that they have an
or not limitation (preventing excessive flow rates), click stop important safety device installed under their bath.
30 CIBSE Journal November 2009 www.cibsejournal.com
CIBSEnov09 pp30-32 PartG.indd 30 22/10/09 16:52:21
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