Aging and decaying Mains Water Pipe Work

Francis Bernstein made this Environmental Information Regulations request to Thames Water
You only have a right in law to access information about the environment from this authority

This request has been closed to new correspondence from the public body. Contact us if you think it ought be re-opened.

The request was partially successful.

Francis Bernstein

Dear Thames Water,

Please can you supply me with the follow information:

1) What is the operational life expectancy that Thames Water use to plan when old mains water pipes are to be replaced?

2) What is the criteria that Thames Water use for planning what areas are to be prioritised, or chosen, for a planned pipe replacement programme?

Yours faithfully,

Francis Bernstein

Dear Thames Water,

Following my EIR request of 21 October 2015, I have yet to have any reply.

Please can you provide an explanation for delaying longer than normally required by law, and your revised date for fulfilling this request.

Yours faithfully,

Francis Bernstein

EIR Requests, Thames Water

Dear Mr Bernstein,

My apologies for the delay in responding to your question(s). I am following up the response to both of your requests and would hope to be able to provide an answer within the next 10 working days. I will keep you updated with my progress.


EIR Officer

show quoted sections

EIR Requests, Thames Water

Dear Ms Bernstein,


Firstly, may I apologise for the delay in responding to your request.   
Please find the response to your request below.  We have addressed your
original questions and the questions in your subsequent clarification.


1.            Background


Your request(s) read as follows:


Please can you supply me with the follow  information:


1) What is the operational life expectancy that Thames Water use to plan
when old mains water pipes are to be replaced?


2) What is the criteria that Thames Water use for planning what areas are
to be prioritised, or chosen, for a planned pipe replacement programme?


Re-submitted questions:


3) Do parts of the Crystal Palace SE19 postcode area have above average
burst water main repairs, compared to other parts of South  London? If the
area has above average, or above expected, number of  burst water mains,
then what is the considered explanation for this?


4) What administrative measures and assessments do Thames Water use  to
track the severity and impact of burst water mains in a local area, either
from multiple small breaks or from larger burst water mains?


This letter provides the response to your request.


2.            Thames Water's response



1)      The working assumption is generally that mains have an 80 year
life expectancy, but many of our older pipes have been shown to be in
near-new condition when exhumed and we do sometime see younger assets to
have exceeded their useful life.  Much work is ongoing In this field
across the industry, and especially in Thames Water, with support from the
University of Surrey and a well-supported Innovation department to plan
and analyse a major programme of testing of our assets to gather better
information, interpret this and better forecast the expected life of our


2)     We use an industry leading model to run a cost benefit calculation
on all of our pipes and to prioritise a programme of replacement based on
the benefits to leakage and burst reduction as well as stakeholder
parameters such as traffic and customer impact. The size of our programme
is determined by the regulator (OFWAT) at the start of an AMP* period and
we operate within these approved parameters. 


3)    Analyses which have been completed internally with data from the
last 5 and 10 years show that some areas around Crystal Palace have
experienced at or above average levels of burst frequency when compared
with other areas of South London when burst numbers are normalised for
pipe length. For reference, the area does not stand out particularly when
compared with areas of North London. Where higher burst frequencies do
exist, we believe the primary driver for this has been primarily related
to the recent poor performance of the local pumping system, which was also
related to several incidents of low pressures experienced by some living
on the highest ground in Crystal Palace. A major project was completed in
April 2015 to address this, with new control methodologies implemented at
both sets of pumps which supply the area as well as back-up power
generation to cover for outages of the power grid and, as a result, the
issue of recurring poor pressures has been resolved.  We continue to
monitor performance of the area in the development of our AMP6 mains
replacement programme and will still be highlighting the worst performing
pipes for replacement where merited.   We expect the overall rate of mains
failures to drop back to be more reflective of South London as a whole.


4)      Mains failures of all types are captured on our internal systems
and the tracking of trends flags up areas of concern to be reviewed for
investment.  For our trunk mains (generally 12” upwards), we have
undertaken analysis to improve our understanding of the consequences of
failures of these assets, which helps drive our investment in these
assets, alongside inferred or actual condition information.  We also have
a significant programme of building and updating our hydraulic models
ongoing over the next 3 years and one of the outputs of this work is to
assess the risk to properties going without water in the event of a
failure on any pipe in the network. Information such as is generated by
this work is used to drive investment in new assets to allow better
resilience in our network such as new valves or cross connections to
provide flexibility in the event of a burst. 


*AMP – Asset Management Period.


The information provided with this letter is taken from the information we
hold on our records as at the date indicated. We cannot guarantee the
accuracy of this information and it should not be relied on for any


Under the Regulations, Thames Water has a duty to individuals requesting
information to make that information available on request and in the
format requested, and must comply with this duty, unless one of the
exceptions contained within the Regulations applies. 


Under the Regulations, we are able to charge a reasonable fee for the


staff time spent locating, retrieving and extracting the information
requested; and printing or copying the requested information and sending
it to the applicant.  The applicable charges are set out on our web site. 
We have of course waived the fee on this occasion but we do reserve the
right to charge for any future request.


3.            Further queries


I understand that you have been in contact with the Information
Commissioner’s Office but should you have any questions, please contact me
by emailing [1][Thames Water request email] 


If you are dissatisfied with the handling of your request, you still have
the right to ask for an internal review.  Internal review requests should
be submitted within six months of the date of receipt of this response and
should be addressed to Environmental Information Requests Manager and
emailed to [2][email address]


If you are dissatisfied with the outcome of the internal review, you can
apply, without charge, to the Information Commissioner, who will consider
whether Thames Water has complied with its obligations under the
Regulations, and can require Thames Water to remedy any problems. You can
find out more about how to do this, and about the Regulations in general,
on the Information Commissioner’s website at: [3] 
Complaints to the Information Commissioner can be made via the "report a
concern" section of the Information Commissioner's website.


Yours sincerely,


EIR Team


Did you know you can manage your account online? Pay a bill, set up a
Direct Debit, change your details or even register a change of address at
the click of a button, 24 hours a day. Please visit

Thames Water Limited (company number 2366623) and Thames Water Utilities
Limited (company number 2366661) are companies registered in England and
Wales each with their registered office at Clearwater Court, Vastern Road,
Reading, Berkshire RG1 8DB. This email is confidential and intended solely
for the use of the individual to whom it is addressed. Any views or
opinions presented are solely those of the author and do not necessarily
represent those of Thames Water Limited or its subsidiaries. If you are
not the intended recipient of this email you may not copy, use, forward or
disclose its contents to any other person; please notify our Computer
Service Desk on +44 (0) 203 577 8888 and destroy and delete the message
and any attachments from your system.

We provide the essential service that's at the heart of daily life.


Visible links
1. mailto:[Thames Water request email]
2. mailto:[email address]