Hong Kong’s

Water Supply
Reducing Lead in Drinking Water

Designed by the Information Services Department

Printed by the Government Logistics Department
Hong Kong Special Administrative Region Government
8/2015
Drinking water supply in Hong Kong
The Water Supplies Department (WSD) is committed
to providing quality drinking water 24 hours a day
to the public. At present, raw water from Dongjiang
and local impounding reservoirs first enters the
water treatment works for a series of stringent and
advanced treatment and disinfection processes.
The treated water fully complies with the World
Health Organization’s (WHO) Guidelines for
Drinking-water Quality. It is delivered via a huge
and enclosed network of pumping stations, service
reservoirs and over 6,000 km of fresh water mains
to the connection point at the lot boundary (i.e. the
boundary between the Government land and the
lot where the customer’s building is located) where
customers reside. It is then routed through the
building’s internal plumbing system which includes
a sump tank, a roof tank, pipes and fittings before
reaching the customer’s tap.

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Maintenance of water
Agent (normally the property
supply system Water Supplies Department management agent or Property Owner/Customer
owners’committees)
Water pipes that join the WSD’s water
mains to the connection point at the lot
boundary are maintained by the WSD.1

The communal service2 including Lot Boundary

the service pipes from the building’s
Roof
lot boundary to the building as well Government Private Tank
as those communal pipes inside the Land Property
building are maintained by the agent
(usually the property management
agent or the owners’ committees).

The inside service of a flat or property

is maintained by the property owner.3

Water
Note 1: Section 4 of the Waterworks Ordinance Pump Meter
(“Ordinance”) stipulates that the duty
of the Water Authority is to supply
water from the waterworks and to
maintain the waterworks. According to Water
Section 2 of the Ordinance, the water Meter
Government Main
pipes that join the WSD’s water mains
to the customers’ connection points at
the lot boundary are the waterworks Sump Water
being the properties maintained by the Tank Meter
Water Authority (i.e. the Director of
Water Supplies).

Note 2: Section 7(2) of the Ordinance stipulates

that the agent of a communal service is
responsible for the maintenance of the Waterworks Communal Service System Inside Service System
communal service.

Note 3: Section 7(1) of the Ordinance stipulates

that the consumer is responsible for
the maintenance of the inside service.

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 How does drinking water get contaminated?
Drinking water can be contaminated in a number of ways after
Conforms to entering the inside service system of a building. Contamination
International
mainly arises from old and worn-out inside service systems, including
Water Standards

aged or rusted pipes, improperly joined pipes, old storage tanks

Quality and faulty water supply pumps. Water can also be contaminated
Conforms to by substandard pipes and fittings installed during construction,
International renovation or replacement of the inside service system.
Standards
Where does lead come from?
Lead is a soft, grey, naturally-occurring heavy metal commonly found
in air, soil, dust, food and water. In daily life, relatively high concentrations
of lead might be found in paint, cosmetics and herbal medicines.

Water quality conforms to international standards Lead pipes were once used extensively in potable water plumbing
systems. In Hong Kong, lead pipes have been banned since the
The quality of drinking water supplied by the WSD fully conforms
1930s whilst other countries such as the United Kingdom (UK)
to the WHO Guidelines. A Water Safety Plan in accordance with
and the United States of America (USA) have banned them since
the WHO Guidelines has been in place since 2007 to further ensure
1970s - 1980s.
a safe water supply to customers.
Galvanized iron (GI) pipes were the most commonly used material
Hong Kong’s water quality monitoring programme is comprehensive
for inside service pipes with a small diametre (100mm and below) in
and stringent. Water quality throughout the supply system is
Hong Kong until they were banned in 1995. From 1995 to the early
systematically and regularly monitored at representative sampling
2000s, lined GI pipes or copper pipes have been widely used as
points for analyses including physical (pH, colour, turbidity, conductivity,
the small-diametre inside service pipes in new buildings. Since the
etc.), chemical (lead, chromium, cadmium, nickel, etc.), radiological,
early 2000s, copper pipes have gradually become the most widely
bacteriological (E.coli, Total Coliform) and biological examinations.
used small-diametre inside service pipe in Hong Kong. They can be
Sampling points cover the water gathering grounds, receiving points joined by soldering or mechanical compression joints. The use of
of Dongjiang water, impounding reservoirs, water treatment works, lead-based soldering to connect copper pipes for potable water use
service reservoirs and distribution mains. The results of the water has been prohibited in Hong Kong since the 1980s.
quality examinations are available on the WSD’s website.
Copper pipes contain less than 0.1% impurities, including lead.
However, copper alloy components with a minor percentage of lead

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 ?
such as valves, taps and other fittings can still Concerted efforts to deal with lead in water
comply with the British Standards or other
accepted standards and are commonly Concerted efforts are needed to minimise the level of lead in drinking
used in the inside service systems of water. It entails the co-operation and participation of all stakeholders
buildings in Hong Kong and worldwide. including the Government, property developers, building contractors,
Authorised Persons, licensed plumbers, plumbing workers, pipes
and fittings suppliers, property owners, property management agents
How does lead get into the and customers.
drinking water?
All materials that come into contact with drinking water (including
Since some pipes or fittings, including pipes, joints, soldering materials, valves, taps and other fittings) shall
valves and taps, may contain a small comply with the relevant British Standards for potable water use.
amount of lead, particularly those made
of copper alloy materials, a small amount Except for works of a minor nature and works which do not involve
of lead can leach into drinking water due connection of copper pipes by soldering, licensed plumbers shall be
to corrosion. employed for the construction, installation, maintenance, repair, etc.
of the inside service system.
Based on the experience of other countries,
excessive lead in water can be caused by the inadvertent or illegal In response to the discovery of excessive lead levels in drinking
use of substandard pipes and fittings. water in some public rental housing (PRH) estates in July 2015,
the WSD has taken a number of measures since July 13 to minimise
the potential risk of contamination by heavy metals from the inside
Factors affecting amount of lead in water service system of new buildings:

Dissolved lead in water is caused by the corrosion of inside service • For all applications for new water supply, if soldering is used in
system components (such as fittings containing lead or lead-based connecting water pipes, a supporting document of lead-free
solders) resulting from chemical reactions between water and the soldering materials is required;
components. The corrosion rate and the amount of lead dissolved into
• Four additional test parameters (Lead, Cadmium, Chromium
water depends on many factors including the water temperature, pH
and Nickel) were added for testing of water samples during
and alkalinity, water hardness, the presence of chloride and dissolved
the final inspection of newly installed fresh water inside service
oxygen, the type of disinfectant applied, the lead content of the
systems in buildings.
components and the duration of contact with water.

In Hong Kong, hydrated lime is added to water leaving the treatment

works to regulate the pH value of the water to 8.2 to 8.8. This will International standards for drinking water supply
effectively reduce the corrosiveness of water and the leaching of lead The WHO produces international norms on water quality and
from components. human health in the form of guidelines that are used as the basis for

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regulation and standard setting For heavy metals, the current international standards are:
in developing and developed
countries worldwide. The WHO’s Parametres New Hong
WHO EU USA

Cadmium
(µg/l) Zealand Kong
guidelines are not the only
international standard.

Nickel
Lead 10# 10 15 10 10
In Hong Kong, the WSD has Cadmium 3 5 5 4 3
pledged to supply fresh water
Chromium 50 50 100 50 50
of quality that totally complies

Lead
with the WHO Guidelines. Nickel 70 20 - 80 70

According to the WHO, # 10 µg/l is approximately equivalent to one drop of water in 40 standard-sized
the guideline values represent swimming pools.

the concentration of constituents

in drinking water that will not
result in any significant health risk
Chromium Brief history of development of
to a person weighing 60kg over limiting value for lead
a lifetime consumption of 2 litres per day The current lead limiting value of 10 µg/litre
for 70 years. As a result, any short-term has evolved by stages over a long
deviation of individual parameters is unlikely to period of time. Before 1984, the
impair health or cause an immediate health risk. The key point is to WHO, the UK and many European
identify the causes of non-compliance and take appropriate remedial countries adopted a standard of
action to rectify the situation. 100 µg/litre. The WHO lowered
Many developed economies such as the European Union, the USA the limit to 50 µg/litre and
and New Zealand have set their own national water quality standards 10 µg/litre in 1984 and 1993 Lead
based on the WHO Guidelines. respectively whilst the UK
and European countries
Due to local variations, there are differences in the limiting values also tightened the limit
of some parameters (e.g. heavy metals) in different countries. to 50 µg/litre and
The acceptable compliance rate, which is normally in the range from 25 µg/litre in 1988 and litre
90% to 99%, also varies from one country to another. In the USA,
for example, if the lead concentration in more than 10% of tap water
2003 respectively. Since
the end of 2013, the EU has
10µg
samples exceeds the action level of 15 µg/litre, the water authority/ formally adopted the WHO
supplier is legally required to collect additional samples, enhance standard of 10 µg/litre.
corrosion control measures and implement an extensive public
education campaign.

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Precautionary measures Use of drinking water
1. If water has not been used overnight, run water taps for one to
In early July 2015, the lead content of some water samples from two minutes each morning before taking any water for drinking or
PRH estates were found to exceed the guideline value set by the cooking. To avoid wastage, you may use a container to collect the
WHO. Subsequently, lead was found in the solder used on the water for non-drinking purposes.
water pipe joints of these estates. The Government has attached
great importance to this matter. An inter-departmental meeting 2. As it is easier for lead in pipes and fittings to leach into hot water,
chaired by the Chief Secretary for Administration was held on only consume water from cold water taps.
July 11 during which decisions were made on crucial follow-up
3. Lead in water cannot be removed by boiling.
work and measures. The Development Bureau has established
a Task Force to determine the cause of the incidents whilst
the Hong Kong Housing Authority (HA) has formed a More easily affected groups
Review Committee on Quality Assurance Issues Relating 4. Alternative source of drinking water such as distilled water
to Fresh Water Supply of Public Housing Estates. should be used for drinking by and cooking for infants, children
The Review Committee is tasked to comprehensively under six, pregnant women and lactating women.4
review the present arrangements for quality control
and monitoring in relation to the fresh water
Water filtration devices
supply systems in PRH estates.
The Chief Executive in Council 5. Not all water filters can remove lead in water. Water filters certified
has approved the setting up of by the U.S. National Sanitation Foundation (NSF) 53 standard are
a Commission of Inquiry under among those recognised to be capable of reducing lead content
the Commissions of Inquiry in water. Most water filters do not have this function.
Ordinance to inquire into
the incidents of excess lead 6. Strictly follow the manufacturer’s instructions on the use and
found in drinking water. maintenance of water filters to achieve the performance claimed
by the manufacturer, including the frequency of replacement
of major parts. Without proper maintenance, water filters may
Before the excess lead
become an ideal breeding ground for bacterial growth.
content issue can be
fully resolved, residents
Note 4: The Government immediately provided bottled water and deployed water
of affected estates can
wagons for tenants of affected housing estates. Tenants can also collect
take the following water from temporary water tanks on the ground floors of the estates and
precautionary measures: temporary water supply systems on respective floors. The Government has
also arranged briefings and provided health information for the tenants and
requested the contractors to conduct investigation and take follow-up action.

In addition, the Government has arranged whole blood lead level tests for
more easily affected people and followed up as appropriate.

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7. As the activated carbon in water filters may reduce the level of involve the connection of
residual chlorine in water, filtered water should be boiled to kill copper pipes by soldering,
the germs before consumption. employ a licensed plumber
to carry out the work and
Inspection of water supply system make sure all materials
that come into contact
8. You may engage an accredited laboratory to take water samples with drinking water
for testing. The list of accredited laboratories is available at the (including all pipes,
website of the Innovation and Technology Commission: joints, soldering
www.itc.gov.hk/en/quality/hkas/doc/Testing_of_lead_and_other_ materials, valves,
heavy_metals_in_water.pdf taps and other
fittings) comply with
9. If the test results show that the level of lead in drinking water the relevant British
does not comply with the WHO standard, you should act Standards for potable
immediately according to the health advice given by the water use.
Centre for Health Protection. For details, please refer to
the website: For information on licensed
www.chp.gov.hk/en/view_content/40398.html plumbers and the approved
water supply pipes and fittings,
10. You should discuss with your estate/building management
water heaters and materials,
office, flat owner or the owners’ committee to engage relevant
please visit the WSD’s website:
professionals, including licensed plumbers, building services
engineers or building surveyors, etc., to inspect the inside service
Licensed Plumber Directory
system to identify the source of excessive lead content and take
www.wsd.gov.hk/en/plumbing_and_engineering/licensed_plumber/
appropriate remedial measures. For the inspection, you can also
index.html
check the completion year of the building and the materials of the
water pipes and fittings. If you suspect that soldering materials
Water Supply Pipes and Fittings, Water Heaters and Materials
with excessive lead content were used to connect pipes, you can
Directory
arrange testing of the lead level of the joint to confirm whether this
www.wsd.gov.hk/en/plumbing_and_engineering/fittings_to_be_
is the source.
installed_or_use/pipes_and_fittings_water_heaters_and_materials/
11. When planning renovation or replacement of pipes and fittings, index.html
except for works of a minor nature and works which do not

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Government action to deal with the The contractors concerned will provide these water filters
lead-in-water issue with NSF 53 certification to households affected by the
lead-in-water issue.
• Testing water samples at public housing estates
• Blood tests
Given public concern over the incident, the Chairman
of the HA announced on July 24, 2015 that the Whole blood lead level is recognised internationally as the most
scope of water sampling for PRH estates would accurate and reliable method for screening and diagnosis when
be extended. The Housing Department and assessing the risk of lead on health. Using hair and urine samples
the WSD are now systematically taking water for screening and diagnosis for lead exposure is not reliable.
samples from over 100 blocks from Such tests are therefore not advisable.
PRH estates completed between Infants and young children aged under six, pregnant women and
2005 and 2010 by batches for lactating women are more easily affected by lead. When the same
testing. The testing work is amount of lead in drinking water is consumed, young children
expected to be completed absorb 4-5 times as much ingested lead when compared with
in September 2015. The next an adult. Children are at a rapid stage of growth, and their
step forward will be planned developing organs and tissues are more susceptible to the toxic
taking into consideration the effects of lead. Moreover, lead absorbed by pregnant women and
experience gained and the lactating women indirectly reaches the fetus and young children.
data collected. As a precautionary measure, these
individuals may make appointments
• Alternative water supply
for blood testing for lead at
As it will take a comparatively longer period of time to draw up a Hospital Authority hospital
a plan to resolve the incident completely, during the transition through the DH. In light
period, the HA has asked the main contractors concerned to take of public concern,
actions to remedy the situation, including extending connection the scope of blood
pipes from the roof-top water tanks to each floor of the building, testing has been
and installing lead-reducing water filters with U.S. NSF 53 expanded at
certification for affected tenants. The HA will consider adjusting discretion to
the arrangements depending on the circumstances. cover children
under eight living
• Providing water filters for affected PRH tenants
in affected estates.
Not all water filters can remove lead from water. Those with
U.S. NSF 53 certification is one type of filters verified to be
lead-reducing. Most water filters do not perform this task.

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• What the blood tests mean
Whole blood
In everyday life, lead is found everywhere and some kind of lead level Actions in different
Health risks
exposure is inevitable. Lead can enter the human body through (microgram/ health care setting
inhalation and ingestion. Notwithstanding this, it is always good decilitre)
for health to achieve the lowest possible lead level in the body.
Taking reference from medical literature as well as local and Normal No significant • DH will inform
overseas experience, the Hospital Authority and the DH health risk individuals about the
have derived the reference values of blood lead level and (Persons below results
18-year-old, No follow-up
corresponding actions to be taken in various health care settings. pregnant women required
For children, pregnant women and lactating women, a blood lead and lactating
level less than 5 microgram/decilitre is considered normal with women: < 5
no significant risk to health. A blood lead level of equal to or more Adults: < 10)
than 5 microgram/decilitre means there is potential risk to health
which requires further health evaluation and follow-up. For adults,
a blood lead level of equal to or more than 10 microgram/decilitre Borderline raised Potential • DH will perform lead
to raised health risk exposure assessment
requires health evaluation and follow-up.
and arrange
(Persons below Health preliminary
• Counselling, treatment and advice
18-year-old, evaluation developmental
The most important and effective pregnant women and follow-up assessment
management is to identify and and lactating required • HA will arrange health
women: 5-44 education, evaluation
stop the source of exposure
so that lead will gradually Adults: 10-50) and monitor blood
be cleared from the lead level
body. The key feature
of the health care Significantly Risk of lead • DH will perform lead
plan is to conduct raised to toxic poisoning exposure assessment
a health risk level and arrange
assessment Need clinical preliminary
according to (Persons below assessment developmental
18-year-old, and follow-up assessment
different blood
pregnant women • HA will arrange
lead levels and and lactating
then take suitable medical assessment,
women: > 44 follow-up and monitor
actions accordingly. blood lead level
Adults: > 50)

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• Investigation and Review Expert quotes
Task Force headed by WSD
“There are many possible causes of ’excessive’ lead in drinking
The Government established
water and blood. Scientific investigation suggests that apart from
a Task Force headed by the
the pollution of construction materials and pipes, environmental
WSD on July 15, 2015 to
pollution (e.g. emissions from vehicles using leaded petrol and
investigate the causes of excessive
lead in contaminated soil), food (e.g. preservatives and seasonings
lead content found in drinking water at public housing estates.
in preserved eggs), cosmetic products (e.g. ingredients of nail
Members include independent experts outside the Government.
polishes) and fishing nets commonly used by fishermen for carrying
The task force will inspect the water pipes, soldered pipe joints
heavy loads are also possible contributing factors... According to
and fittings of the estates concerned. It will recommend measures
the WHO Guidelines, the concentration of constituents in drinking
to prevent recurrence of similar incidents in future.
water, if complying with the WHO standard, will not result in any risk
Review Committee on Quality Assurance Issues Relating to of lead-related diseases to an adult of normal weight over a lifetime’s
Fresh Water Supply of Public Housing Estates consumption for 70 years. As to how many years a person will catch
On July 24, 2015, the HA set up the Review Committee on diseases by drinking water containing excessive lead, it varies among
Quality Assurance Issues Relating to Fresh Water Supply of individuals and places. The medical sector should give careful
Public Housing Estates to comprehensively review the present diagnoses and conduct detailed studies in respect of individual
arrangements for quality control and monitoring in relation to cases, so as to provide targeted precautions and treatment. Even if
the installation of fresh water supply systems in public the lead content in drinking water exceeds the Guideline’s limit in the
housing estates. short term or intermittently, we can still minimise the risk of diseases
by timely detection and taking early control of the problem.”
Independent Commission of Inquiry Professor Ho Kin Chung,
At a special Executive Council meeting on August 13, 2015, Dean of the School of Science and Technology at
the Chief Executive in Council approved the setting up of the Open University of Hong Kong and
a Commission of Inquiry under the Commissions of Inquiry former Chairman of the Advisory Committee on the Quality of Water Supplies
Ordinance (Cap. 86) to inquire into the incidents of excess lead
found in drinking water. Its terms of reference are to: (a) ascertain
“Although lead is toxic, most minor exposures will not result in clinical
the causes of excess lead found in drinking water in public rental
poisoning. For those residents with a mildly elevated blood lead level,
housing developments; (b) review and evaluate the adequacy
if further exposure is avoided, their health should not be much
of the present regulatory and monitoring system in respect of
affected.”
drinking water in Hong Kong; and (c) make recommendations
with regard to the safety of drinking water in Hong Kong. Hong Kong Society of Clinical Toxicology

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“Children who have already been exposed to environmental lead Useful information and websites
with elevated blood lead levels most often do not show any clear
physical signs or specific symptoms. Symptoms that do arise include Lead in Drinking Water Incidents
tiredness, muscle ache, headaches, gastrointestinal issues, irritability www.isd.gov.hk/drinkingwater/eng/
and difficulty in concentration. Other developmental deficits in Commission of Inquiry into Excess Lead Found in Drinking Water
cognitive function, attention and academic achievement may occur. www.coi-drinkingwater.gov.hk/eng/index.html
These symptoms and developmental problems can also be
Transport and Housing Bureau
associated with many other common illnesses and factors. It must
www.thb.gov.hk/en/index.htm
be emphasised that developmental or behavioural problems usually
have multifactorial aetiologies. Ensuring a currently safe lead-free Development Bureau
environment is essential. For children with a history of lead exposure, www.devb.gov.hk/en/home/index.html
besides monitoring their developmental progress, provision of a Food and Health Bureau
nurturing and stimulating family environment should contribute to www.fhb.gov.hk/en/index.html
amelioration of any potential developmental effects, and promote
optimal and healthy development for these children.” Housing Department
www.housingauthority.gov.hk/en/index.html
Developmental-Behavioural Paediatrics Subspecialty Board
Hong Kong College of Paediatricians Water Supplies Department
www.wsd.gov.hk/en/home/index.html

Department of Health
Telephone hotlines www.dh.gov.hk/eindex.html
Department of Health Centre for Health Protection
2125 1122 www.chp.gov.hk/en/index.html

Hospital Authority
Water Supplies Department
www.ha.org.hk/visitor/ha_index.asp
2824 5000
Water Safety Plan
Housing Authority www.wsd.gov.hk/en/water_resources/water_safety_plan/index.html
2712 2712
Guidelines for Drinking-water Quality, fourth edition
whqlibdoc.who.int/publications/2011/9789241548151_eng.pdf

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