Water Composition
How to find out about the composition of your tap water – public water supplies
A
consumer may request information from their water supplier about their
water supply. The supplier must provide information about the
consumer’s supply free of charge and within seven days. Where the
request relates to information outside the consumer’s supply zone, a
reasonable fee may be charged for provision of the information.
Most water suppliers
provide this information online and Water UK publishes a
listing of
website addresses for all water suppliers in England and Wales as well
as the Island Water Authorities (Guernsey Water, Jersey Water, Council
of the Isles of Scilly & Isle of Man). In Scotland, the Drinking
Water Quality Regulator for Scotland provides
information on drinking
water quality while in Northern Ireland,
Northern Ireland Water
provides that information. Many suppliers offer a postcode based search
facility allowing online access to data. Some provide the information
online at the supply zone level and it is necessary for the consumer to
find out in which supply zone their premises are located. A few
suppliers will only provide information about drinking water quality in
response to an E-mail or letter.
How to find out about the composition of your tap water – private water supplies
Local authorities maintain
comprehensive records about the private water supplies in their areas.
Where a consumer receives water from a private water supply, it will be
necessary to contact the local authority to find out what analysis data
is available.
Why information about the composition of water might be required
Consumers may need detailed
information on the quality and composition of water supplied to their
own premises for a number of reasons:
Water heaters and combination boilers
Hard water causes the build up of
scale in kettles, washing machines, boilers and hot water systems. The
deposition of scale can damage heating elements and make the heating
process less efficient. For this reason, Government guidance given in
the
Domestic Heating Compliance Guide requires that “where the mains
water hardness exceeds 200 parts per million (
as CaCO3), provisions should be made
to treat the feed water to water heaters and the hot water circuit of
combination boilers to reduce the rate of accumulation of lime scale”.
Softening and water conditioning equipment
Information about the
hardness of drinking water is important when deciding whether to
install water softening or water conditioning equipment. Hard water
increases the quantity of soap, washing up liquid and washing powders
required for washing and cleaning and also causes staining and deposits
on sanitary ware. There is also anecdotal evidence that softened water
can reduce skin irritation although a
research study at Nottingham University to investigate whether water softeners help
reduce the severity of eczema showed no objective difference in outcomes between the children whose homes were fitted with a water softener and those without.
Maps showing hardness levels in water supplies throughout the UK are
available but some water
hardness maps provide insufficient detail and pockets of relatively soft
water are found within regions shown as hard water areas. A more detailed map
can be viewed on the DWI
website in the Water Hardness Advice Leaflet but the scale is too small to
allow precise location of premises near boundaries of hard/soft water areas. .
For this reason you should ask your water supplier for information specific to
your premises.
Water softening equipment should be installed in accordance with WRAS
Guidance IGN 9-07-01,
which specifies, among other things that a separate supply of un-softened water
should be provided for potable purposes.
Corrosion of household water supply systems – public water supplies
Chemical, physical and biological characteristics of water can influence
corrosion of pipes and fittings. The regulatory requirement on water suppliers
to reduce contamination from pipes has resulted in public water supplies that
are not unduly corrosive towards metals and alloys used in water supply
systems. Nevertheless some public water supplies may cause
dezincification
of brass fittings (See also
WSAA84). In these cases the specification of dezincification
resistant fittings is important when installing or re-furbishing water supply
systems. Other more complex factors can cause accelerated corrosion of copper
pipes and this subject is addressed in the FWR ROCK “Causes of Copper Corrosion
in Plumbing Systems” which is available on
this website.Corrosion of
household water supply systems – private water supplies
The absence, or inadequacy, of suitable treatment results in many
private supplies being corrosive towards the metals and alloys used in water
supply systems. The greatest concern will be the risk to health from lead and
other toxic metals, but corrosion of pipes and fittings, discolouration of
laundry and sanitary ware and taste complaints are all associated with
corrosive attack on plumbing systems. Information about water composition and
implications for corrosion control is given in the “Manual on Treatment for
Small Water Supply Systems”, which can be accessed on the
DWI
website.. A more detailed description of how the chemical composition of
water affects its corrosion potential is available on the
Wilkes University
website
Where
tap water is water is to be used in brewing, the concentration of some
inorganic salts, as well as the pH and alkalinity of the water can have
a significant effect on the fermentation process.
For more information.
Where an aquarium or fishpond is
filled or topped up with tap water the hardness, pH, alkalinity and the
nitrate and ammonium ion levels will be of interest.
For more
information. Note that water used in ponds and aquaria must be
de-chlorinated in order to avoid fish mortalities.