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Subject: Water Management in London
Report to: Environment Committee
Report of: Executive Director of Secretariat
Date: 24 October 2013
This report will be considered in public
1.
Summary
This report sets out background information for a discussion with Thames Water about water
management in London.
2.
Recommendations
2.1
That the Committee notes this report as background to discussing water management in
London with Thames Water.
3.
Background
3.1
Water management for a city like London is a major challenge. Piped water for homes and
businesses, must be gathered from natural or other sources, treated and distributed. Used waste
water must also be safely gathered and processed to deal with harmful contaminants. Finally,
rainwater and other drainage must be safely handled to avoid flooding. These issues are
addressed in the Mayor’s Water Strategy1, and this meeting will contribute to the Committee’s
ongoing scrutiny of the strategy’s implementation.
3.2
Decisions on many of these issues are made in water companies’ business plans and Water
Resource Management Plans, on a five-year cycle. Plans for the next cycle, covering 2015-20,
are currently being drafted and require approval by Ofwat. The main plan of relevance to
London is that of Thames Water, which provides water to most of London and sewerage
services to nearly all of it.
http://www.london.gov.uk/priorities/environment/vision-strategy/water
City Hall, The Queen’s Walk, London SE1 2AA
Enquiries: 020 7983 4100 minicom: 020 7983 4458 www.london.gov.uk
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3.3
The Assembly has previously made reports about water management, most recently:

Water Matters: efficient water management in London2

For a Rainy Day: the Mayor’s role in managing London’s flood risk in the event of severe
rainfall3

London Assembly response to Thames Tunnel proposals4
4.
Issues for Consideration
4.1
Treating and supplying water has financial and environmental costs, so reasonable steps should
be taken to improve water efficiency in London’s homes and businesses, and to reduce the loss of
treated water from leaking pipes across the distribution network.
4.2
In its 2012 report Water Matters, the former Health and Environment Committee reported that
about a quarter of London’s treated water is lost to leakage – this figure has reduced from
previous higher levels, but there are financial, environmental and social costs to the digging and
other work necessary to find and fix leaks, so further reductions are a challenge. The Committee
recommended that decisions on leakage reduction and other investments in water infrastructure
should fully reflect the environmental as well as financial and social costs and benefits. Ofwat is
due to set new leakage targets from 2015.
4.3
The other main area where there is scope to reduce the costs of water supply is in efficiency.
London’s consumers use more water than the national average and there is relatively easy scope
for usage reduction in most households. An important driver for efficient usage would be more
widespread water metering. Currently, only about a quarter of London’s households have a
meter. Investment in meter installation and the regulation of compulsory metering will be part
of the decisions on the 2015-20 plans.
4.4
Metering could well increase bills for some households, especially those with high water usage
for the size of the property. To avoid excessive inequitable impacts on vulnerable households,
the Committee sought proposals from water companies on ‘social tariffs’ to protect vulnerable
households’ essential use of water for well-being, without encouraging excessive use.
4.5
London suffers from rapid run-off of rain water due to the high percentage of its surface covered
in roads, buildings, pavements, car parks and other impermeable surfaces. The city’s surface
drainage systems must allow rain water to run away from areas used by people and vehicles,
without allowing it to cause floods elsewhere. In many parts of London, particularly inner
London, there is an additional challenge posed by the historical sewage network, which uses the
same pipes to carry domestic waste and surface runoff. The network has overflow channels to
the river Thames, meaning that there are frequent discharges of untreated sewage into the river,
whenever there is significant rainfall.
4.6
The proposed solution is to construct a new ‘interceptor’ sewer, the Thames Tideway Tunnel, to
capture sewage overflow and take it to treatment works, without allowing it to enter the river
http://www.london.gov.uk/mayor-assembly/london-assembly/publications/water-matters-efficient-water-managementin-london
3 http://www.london.gov.uk/mayor-assembly/london-assembly/publications/for-a-rainy-day
4 http://www.london.gov.uk/mayor-assembly/london-assembly/publications/assembly-response-to-thames-tunnelproposals
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untreated. In 2010 the Health & Public Services Committee responded on behalf of the
Assembly to Thames Water’s consultation on this proposal and concluded that it was a
necessary scheme.
4.7
Another way to approach the challenge of surface water drainage is to implement sustainable
urban drainage systems (SUDS). These operate on the principle that water should be held close
to where it falls, either soaking into the ground or being retained in ponds, tanks or other
containment for gradual release. These systems help prevent sharp peaks of water flow through
the drainage network and therefore overflow events or floods.
4.8
In its report For a Rainy Day, this Committee fully supported the implementation of SUDS in
London, but did not conclude that it would be possible or affordable to install enough SUDS
quickly enough to avoid the need for the Tideway Tunnel.
4.9
The Thames Tideway Tunnel is expected to cost in the region of £4 billion, funded largely by
water bill payers and leading to an increase of about £70 on the average annual sewage bill of
Thames Water’s customers (for sewage, nearly all Londoners). This would be an element of the
business plan for 2015-20 to be decided on by Ofwat in the current round of approvals.
4.10
There is also an interim application by Thames Water to increase bills for 2014/15 by about
£29 on average. Only a relatively small element of this would reflect the early costs of the
Tideway Tunnel; more of the application is about unexpected levels of bad debt associated with
the economic downturn, and additional costs to Thames Water of taking over lengths of sewer
previously the responsibility of private households and businesses. An interim response by
Ofwat to this application is expected this month, potentially before the meeting.
4.11
Invited guests
The Committee expects to put questions about water management in London to Thames Water,
as the provider of water supplies to most of London and of sewerage services to nearly all of
London. One or more other relevant organisations may also be present to provide additional
views.
5.
Legal Implications
5.1
The Committee has the power to do what is recommended in the report.
6.
Financial Implications
6.1
There are no financial implications to the Greater London Authority arising from this report.
List of appendices to this report: None
Local Government (Access to Information) Act 1985
List of Background Papers: None
Contact Officer:
Telephone:
E-mail:
Ian Williamson
020 7983 6541
[email protected]