Cryptosporidia oocysts in drinking water

Dr.Howard T Dryden 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. Contact us if you think it should be reopened.

Thames Water did not have the information requested.

Dr.Howard T Dryden

Dear Thames Water,

1. Can you advise the concentration of cryptosporidia oocysts that will need to be detected before you warn the public and turn off the water supplies.

2. Do you monitor for oocysts continuously, or just take spot samples. If you take samples, what is the sample frequency

2. What percentage of the water supply is treated by ultra filtration and standard rapid gravity sand filters.

Yours faithfully,

Dr.Howard T Dryden

Thames Water

1 Attachment

Thank you for your email.

Your query is now under investigation with a dedicated member of Thames
Water's Customer Relations team and I would like to make sure that we fully
investigate any points or answer any questions you have raised before we
reply to you.

The advisor will continue to liaise with you until we resolve your case and
usually telephone you to discuss the solution. If this is not possible,
they will email you by 18/02/2011 at the latest.

Occasionally, investigations can take longer than expected and if this is
the case I will ensure you are kept informed of the progress being made.

Thank you for your patience while we look into this matter.

For your reference I have attached our quality promise leaflet.

Yours sincerely

Justin Hulbert
Customer Relations Manager

Further contact information

You might require our urgent operational assistance. For example, you may
need us to visit your property or to repair part of our water or wastewater
network. If this is the case, please call us on 0845 9200 800.

If you wish to let us know that we have a leak on our pipework, please call
our free leakline number on 0800 714614.

If you have concerns about your water bill, meter readings or payments,
that require our earlier attention, please call 0845 9200 888 with your
ten-digit account number to hand.

Emailing us: Please do not reply to this email address as it is not
monitored. Should you wish to contact us by email again, please follow the
link below or copy and paste it into your web browser:

http://www.thameswater.co.uk/contactus

(See attached file: Our Quality Promise.pdf)

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

customer.feedback@thameswater.co.uk, Thames Water

1 Attachment

Thames Water
Customer Relations
Customer Services
P.O. Box 436
Swindon
SN38 1TU

Telephone: 08457 200897
Fax: 01793 424291
E-mail: [Thames Water request email]

10 February 2011

Our Ref: 723698

Cryptosporidia oocysts

Dear Dr Dryden

Thank you for your email of 4 February, concerning Cryptosporidia oocyts in
drinking water. Having
consulted with our Water Quality team, I am able to advise you of the
following:

We do not have a defined limit for Cryptosporidia oocysts that, once
exceeded, would result in
restriction of use advice being delivered to downstream customers. The
decision to restrict use of
water would be taken by the Water Quality Manager after consultation with
the regional Health
Protection Unit and, in some cases, the Company's retained Public Health
Consultant. This decision
would only be taken after a public health risk assessment had been
conducted, with factors such as
raw water quality, treatment process performance and volume and
distribution of the contaminated
water had been considered.

Following the detection of even a single oocyst in the final water at a
Water Treatment Works (WTW),
investigations are undertaken and the Health Protection Unit(s) are
notified. However, in the vast
majority of cases, it is not considered appropriate to issue restriction of
use advice to downstream
customers, following a public health risk assessment.

All our Water Treatment Works are assessed to determine the risk of
Cryptosporidium within the raw
water and the treatment processes in place that would remove oocysts, such
as slow-sand filtration.
At sites considered to be at significant risk of Cryptosporidium,
continuous monitoring is undertaken on
the final treated water as a minimum, via the use of a Filtamax continuous
flow sampling system. This
system continuously filters a sample of the final water, with any oocysts
present in the sample
being captured on a filter cartridge. This cartridge is periodically
removed/replaced and delivered to
our laboratory for analysis.

Due to variable outputs from the individual WTW's it is difficult to
provide a specific percentage of
treatment works that treat water by volume. However, there are currently
102 works in operation, and
of these:

- 25 are equipped with standard Rapid Gravity Filtration
- 5 are equipped with slow sand filtration
- 3 are equipped with membrane filtration (of which, 2 utilise micro
filtration and one utilises ultra
filtration).

Please note that this list does not include our newly-commissioned
desalination plant in Beckton,
which includes ultra-filtration and reverse osmosis processes.

I do hope that the above information is useful to you and satisfactorily
answers the questions you
posed.

Yours sincerely

Charlie Broadbridge
Customer Relations
Enc. The Thames Water quality promise leaflet

Visit www.thameswater.co.uk to use our on-line forms or to find out about
paperless billing

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

Dr.Howard T Dryden

Dear [email address],

Dear sir,
Thank you for your e.mail.

1.I note that you have dropped the trigger point of more than 1 oocysts per 10 litres of water, and that you no longer have a formal performance standard for the quality of the water.

2.The technique used for oocyst analysis is not a continuous process but a batch analytical technique that does not detect break-through of oocysts until after the event

3.RGF filters are subjected to transient worm-hole channeling and will discharge oocysts into the water, especially after a filter back-wash

From your comments I conclude that the cryptosporidium risk associated with drinking mains water in Thames region remains unchanged, and indeed because the region no longer adopts a formal standard it would seem that risks and potential hazard associate with the water have increased.

I would have hoped that Thames would have installed continuous on-line monitoring for oocysts, and would now be using filter media not subjected to biofouling and wormhole channeling.

Yours sincerely,

Dr.Howard T Dryden

Thames Water

1 Attachment

Thank you for your email.

Your query is now under investigation with a dedicated member of Thames
Water's Customer Relations team and I would like to make sure that we fully
investigate any points or answer any questions you have raised before we
reply to you.

The advisor will continue to liaise with you until we resolve your case and
usually telephone you to discuss the solution. If this is not possible,
they will email you by 01/03/2011 at the latest.

Occasionally, investigations can take longer than expected and if this is
the case I will ensure you are kept informed of the progress being made.

Thank you for your patience while we look into this matter.

For your reference I have attached our quality promise leaflet.

Yours sincerely

Justin Hulbert
Customer Relations Manager

Further contact information

You might require our urgent operational assistance. For example, you may
need us to visit your property or to repair part of our water or wastewater
network. If this is the case, please call us on 0845 9200 800.

If you wish to let us know that we have a leak on our pipework, please call
our free leakline number on 0800 714614.

If you have concerns about your water bill, meter readings or payments,
that require our earlier attention, please call 0845 9200 888 with your
ten-digit account number to hand.

Emailing us: Please do not reply to this email address as it is not
monitored. Should you wish to contact us by email again, please follow the
link below or copy and paste it into your web browser:

http://www.thameswater.co.uk/contactus

(See attached file: Our Quality Promise.pdf)

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

customer.feedback@thameswater.co.uk, Thames Water

Thames Water
Customer Relations
Customer Services
P.O. Box 436
Swindon
SN38 1TU

Telephone: 08457 200897
Fax: 01793 424291
E-mail: [Thames Water request email]

21 February 2011

Our Ref: 723698

Cryptosporidia oocysts

Dear Dr Dryden

Thank you for your email of 15 February 2011, concerning the above and in
which you raise further
questions.

Having spoken again to my colleagues in our Water Quality team, I have been
advised that the
'one oocyst per 10L' standard was dropped at the start of 2008, by our
Regulator, the Drinking Water
Inspectorate (DWI). This amended regulation applies to all water companies
and not just ourselves.
We are now obliged to notify the detection of even a single oocyst, whereas
prior to this regulatory
change, only those results exceeding the standard would have been notified.

Further information about the current regulations regarding Cryptosporidium
in drinking water can be
obtained from the DWI website at www.dwi.gov.uk.

As an end-point monitoring process, the use of a Filtamax sampling system
will only detect oocysts
once they are present within the sample stream. This is the DWI approved
process for monitoring of
Cryptosporidia oocysts. However, all Water Treatment Works (WTW's) are
assessed across
upstream points (including the raw water catchment) to determine the risk
of Cryptosporidium and,
where such risks are identified, appropriate mitigation measures are put in
place.

With regard to RGF filters, generally speaking, we do not rely solely on
RGFs as a primary barrier to
Cryptosporidium. Slow-sand filtration or membrane filtration are
preferred, due to the greater particle
removal efficiency that they offer.

However, at those works where we do employ an RGF process, our Best
Operating Practice
guidelines require that individual filters are run to waste for a period
after backwashing to allow the
filter to 'settle' and return to satisfactory particle removal operating
efficiency.

It is acknowledged that the risk associated with Cryptosporidium in the
drinking water remains
unchanged as both our treatment processes and monitoring regime remain
unchanged.

However, as previously stated, since 2008 we now report any detection of
oocysts, as opposed to only
instances that exceeded the previous one per 10L standard, to both the DWI
and the appropriate
Health Protection Unit. It is therefore considered the hazard associated
with Cryptosporidium in
potable water has not increased.

The system employed for Cryptosporidium oocyst monitoring in the final
water is the best available
technique, as opposed to, for example, 'grab samples' using 10L barrels; I
should highlight that these
systems are supported by online turbidity monitoring, which is standard
practice for the industry.

I trust that the above information fully explains our sampling methodology.


Yours sincerely

Charlie Broadbridge
Customer Relations

Visit www.thameswater.co.uk to use our on-line forms or to find out about
paperless billing

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

Dr.Howard T Dryden

Dear [email address],

Thank you for the information.

Can you advise the percentage or water treated by RGF filters in Thames region?

You state that you monitor for oocysts up-stream as well as down-stream from the filters. I would appreciate if you could forward me a copy of the reports for the RGF treatment works operated by Thames water, giving the number of oocysts that you have detected both up-stream and down-stream of the filters over the past 12 months.

I would appreciate it if you could also include the average turbidity readings in NTU units before and after the RGF filters for the treatment works operated by Thames Water.

Given the above information, this should complete my FOI request.

Yours sincerely,

Dr.Howard T Dryden

Thames Water

1 Attachment

Thank you for your email.

Your query is now under investigation with a dedicated member of Thames
Water's Customer Relations team and I would like to make sure that we fully
investigate any points or answer any questions you have raised before we
reply to you.

The advisor will continue to liaise with you until we resolve your case and
usually telephone you to discuss the solution. If this is not possible,
they will email you by 07/03/2011 at the latest.

Occasionally, investigations can take longer than expected and if this is
the case I will ensure you are kept informed of the progress being made.

Thank you for your patience while we look into this matter.

For your reference I have attached our quality promise leaflet.

Yours sincerely

Justin Hulbert
Customer Relations Manager

Further contact information

You might require our urgent operational assistance. For example, you may
need us to visit your property or to repair part of our water or wastewater
network. If this is the case, please call us on 0845 9200 800.

If you wish to let us know that we have a leak on our pipework, please call
our free leakline number on 0800 714614.

If you have concerns about your water bill, meter readings or payments,
that require our earlier attention, please call 0845 9200 888 with your
ten-digit account number to hand.

Emailing us: Please do not reply to this email address as it is not
monitored. Should you wish to contact us by email again, please follow the
link below or copy and paste it into your web browser:

http://www.thameswater.co.uk/contactus

(See attached file: Our Quality Promise.pdf)

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

customer.feedback@thameswater.co.uk, Thames Water

Thames Water
Customer Relations
Customer Services
P.O. Box 436
Swindon
SN38 1TU

Telephone: 08457 200897
Fax: 01793 424291
E-mail: [Thames Water request email]

24 February 2011

Our Ref: 723698

Cryptosporidia oocysts

Dear Dr Dryden

Thank you for your email of 21 February 2011, seeking further information
on the above subject.

The percentage of water treated by Rapid Gravity Filters (RGF's) is
difficult to determine, as I outlined
in my response to your original email, dated 4 February.

This is because of the variable outputs from the individual Water Treatment
Works. It is difficult to
provide a specific percentage of treatment works that treat water by
volume. There are currently 102
works in operation, and of these:

- 25 are equipped with standard RGF
- 5 are equipped with slow sand filtration
- 3 are equipped with membrane filtration (of which, two utilise micro
filtration and one utilises
ultra filtration).

I think there has been some confusion regarding the monitoring of oocysts
upstream of the filters. In
my previous response to this enquiry, I stated that "all Water Treatment
Works (WTW's) are assessed
across upstream points (including the raw water catchment)".

While this is correct, it refers to the Cryptosporidium risk assessment,
which looks at various features
of the catchment, such as geology, local agricultural activity and whether
the water source is surface
water or groundwater derived. It does not, however, refer to Filtamax
monitoring of oocysts upstream
of the RGF's (where present).

With regard to providing data concerning turbidity levels through our
treatment works, may I suggest
that you contact the Drinking Water Inspectorate (DWI). All analytical
data that is collected in line with
our statutory monitoring programme, in accordance with the Water Supply
(Water Quality) (England
and Wales) Regulations 2000, is submitted to the DWI on an annual basis.
Their website address is
www.dwi.gov.uk.

I hope that the above clarifies the situation.

Yours sincerely

Charlie Broadbridge
Customer Relations

Visit www.thameswater.co.uk to use our on-line forms or to find out about
paperless billing

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

Dr.Howard T Dryden

Dear [email address],

I have reviewed the information held by the DWI with regards to Thames water as you requested.

There is no information on oocyst levels in your feed water supply, or results for your bulk water supply.
I note that in 2009 Thames water exceeded turbidity levels on 9 occasions.

The Milwaukee crypto outbreak confirms that it only takes one accident, and that even if your turbidity levels are low then there is still a risk of oocysts passing into the public supply, especially with RGF sand filters.

Do you have any information regarding turbidity levels before and after your treatment works and do you have any data available regarding oocysts concentrations before and after the filters of each of your treatment works.

If you do not have this information available then please let me know.

Yours sincerely,

Dr.Howard T Dryden

Thames Water

1 Attachment

Thank you for your email.

Your query is now under investigation with a dedicated member of Thames
Water's Customer Relations team and I would like to make sure that we fully
investigate any points or answer any questions you have raised before we
reply to you.

The advisor will continue to liaise with you until we resolve your case and
usually telephone you to discuss the solution. If this is not possible,
they will email you by 05/04/2011 at the latest.

Occasionally, investigations can take longer than expected and if this is
the case I will ensure you are kept informed of the progress being made.

Thank you for your patience while we look into this matter.

For your reference I have attached our quality promise leaflet.

Yours sincerely

Justin Hulbert
Customer Relations Manager

Further contact information

You might require our urgent operational assistance. For example, you may
need us to visit your property or to repair part of our water or wastewater
network. If this is the case, please call us on 0845 9200 800.

If you wish to let us know that we have a leak on our pipework, please call
our free leakline number on 0800 714614.

If you have concerns about your water bill, meter readings or payments,
that require our earlier attention, please call 0845 9200 888 with your
ten-digit account number to hand.

Emailing us: Please do not reply to this email address as it is not
monitored. Should you wish to contact us by email again, please follow the
link below or copy and paste it into your web browser:

http://www.thameswater.co.uk/contactus

(See attached file: Our Quality Promise.pdf)

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

customer.feedback@thameswater.co.uk, Thames Water

Thames Water
Customer Relations
Customer Services
P.O. Box 436
Swindon
SN38 1TU

Telephone: 08457 200897
Fax: 01793 424291
E-mail: [Thames Water request email]

29 March 2011

Our Ref: 723698

Cryptosporidia oocysts

Dear Dr Dryden

Thank you for your email of 22 March 2011

I am unable to provide operational information regarding pre-filtration and
post-filtration turbidity and
Cryptosporidium oocysts.

However, as detailed in previous correspondence, all results of statutory
samples (i.e. those collected
from the water entering supply from a water treatment works) are submitted
to the Drinking Water
Inspectorate (DWI) and I recommend any request for such information is made
to this regulator.
Similarly, all detections of Cryptosporium oocysts in the final water are
notified to the DWI and this
information should also be available through them.

I hope this clarifies the matter.

Yours sincerely

Geoff Parker
Customer Relations

Visit www.thameswater.co.uk to use our on-line forms or to find out about
paperless billing

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

Dr.Howard T Dryden

Dear [email address],

Thank you for your reply;

I understand that you unable to provide operational information regarding pre-filtration and post-filtration turbidity and Cryptosporidium oocysts levels.

The DWI do not hold this information.

When you say you are unable to provide the data, perhaps you could reply to the following final question.

a. You do not have the data
b. Or you have the data by can not provide me with the information

Yours sincerely,

Dr.Howard T Dryden

Thames Water

1 Attachment

Thank you for your email.

Your query is now under investigation with a dedicated member of Thames
Water's Customer Relations team and I would like to make sure that we fully
investigate any points or answer any questions you have raised before we
reply to you.

The advisor will continue to liaise with you until we resolve your case and
usually telephone you to discuss the solution. If this is not possible,
they will email you by 13/04/2011 at the latest.

Occasionally, investigations can take longer than expected and if this is
the case I will ensure you are kept informed of the progress being made.

Thank you for your patience while we look into this matter.

For your reference I have attached our quality promise leaflet.

Yours sincerely

Justin Hulbert
Customer Relations Manager

Further contact information

You might require our urgent operational assistance. For example, you may
need us to visit your property or to repair part of our water or wastewater
network. If this is the case, please call us on 0845 9200 800.

If you wish to let us know that we have a leak on our pipework, please call
our free leakline number on 0800 714614.

If you have concerns about your water bill, meter readings or payments,
that require our earlier attention, please call 0845 9200 888 with your
ten-digit account number to hand.

Emailing us: Please do not reply to this email address as it is not
monitored. Should you wish to contact us by email again, please follow the
link below or copy and paste it into your web browser:

http://www.thameswater.co.uk/contactus

(See attached file: Our Quality Promise.pdf)

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

Dr.Howard T Dryden

Dear Thames Water,

Thank you for your reply.

Turbidity levels before and after the filters as well as oocyst levels before and after the filters are your most fundamental water quality parameters required to ensure the health and well being of the public.

The UK has the highest level of cryptosporidiosis in Europe (Eurosurveillance, Volume 12, Issue 5, 01 May 2007) , in relation to German the incident rate in the UK is 6 times higher, and considering that the fatality rate is 1 in 400, this is a matter of concern.

I would have thought you would have the information available in digital format, however I have now been waiting for the data since the 4th of February.

The data published by the DWI is useful but not relevant to this information request for the reason stated in earlier correspondence.

I can only conclude you do not have the information, in which case there are serious health and safety issues at stake. Alternatively you have the information but do not want to make it available which is equally disturbing because if there were no problems that I am sure you would be only too willing to publish the results.

Yours faithfully,

Dr.Howard T Dryden

customer.feedback@thameswater.co.uk, Thames Water

Thames Water
Customer Relations
Customer Services
P.O. Box 436
Swindon
SN38 1TU

Telephone: 08457 200897
Fax: 01793 424291
E-mail: [Thames Water request email]

05 April 2011

Our Ref: 723698

Cryptosporidia oocysts

Dear Dr Dryden

Thank you for your email of 30 March 2011.

In response to your latest enquiry, I can confirm that the operational data
related to your previous
enquiry is indeed recorded by our control systems. Despite this I am unable
to provide information of
this nature.

I trust this has clarified the situation.
Yours sincerely

Geoff Parker
Customer Relations

Visit www.thameswater.co.uk to use our on-line forms or to find out about
paperless billing

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3587 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

Dr.Howard T Dryden

Dear customer.feedback@Thames water.co.uk,

Thank you for your reply and I am disappointed that you can not provide me with water turbidity data or cryptosporidium oocyst numbers before and after the filters of your drinking water treatment facilities.

From your previous reply I understand that you have recorded all the data in digital format so the information is available to send.

Please therefore provide me with a valid reason why you do not wish to make the information available in compliance to the information request.

Yours sincerely,

Dr.Howard T Dryden

Thames Water

1 Attachment

Thank you for your email.

Your query is now under investigation with a dedicated member of Thames
Water's Customer Relations team and I would like to make sure that we fully
investigate any points or answer any questions you have raised before we
reply to you.

The advisor will continue to liaise with you until we resolve your case and
usually telephone you to discuss the solution. If this is not possible,
they will email you by 29/04/2011 at the latest.

Occasionally, investigations can take longer than expected and if this is
the case I will ensure you are kept informed of the progress being made.

Thank you for your patience while we look into this matter.

For your reference I have attached our quality promise leaflet.

Yours sincerely

Justin Hulbert
Customer Relations Manager

Further contact information

You might require our urgent operational assistance. For example, you may
need us to visit your property or to repair part of our water or wastewater
network. If this is the case, please call us on 0845 9200 800.

If you wish to let us know that we have a leak on our pipework, please call
our free leakline number on 0800 714614.

If you have concerns about your water bill, meter readings or payments,
that require our earlier attention, please call 0845 9200 888 with your
ten-digit account number to hand.

Emailing us: Please do not reply to this email address as it is not
monitored. Should you wish to contact us by email again, please follow the
link below or copy and paste it into your web browser:

http://www.thameswater.co.uk/contactus

(See attached file: Our Quality Promise.pdf)

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3333 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.

customer.feedback@thameswater.co.uk, Thames Water

Thames Water
Customer Relations
Customer Services
P.O. Box 436
Swindon
SN38 1TU

Telephone: 08457 200897
Fax: 01793 424291
E-mail: [Thames Water request email]

19 April 2011

Our Ref: 723698

Cryptosporidia oocysts - Releasing of information

Dear Dr Dryden

Thank you for your email of 13 April 2011.

I am sorry to disappoint you in your request for information. However as
this request is not subject to the Environmental Information Act 2004, we
have made the decision that the data will not be released.

This is for reasons of company confidentiality, however there are also
difficulties
regarding the practicality of providing the amount and type of data you
have requested.

I trust this clarifies the matter.

Yours sincerely

Geoff Parker
Customer Relations

Visit www.thameswater.co.uk to use our on-line forms or to find out about
paperless billing

Find juggling your finances a struggle? Spread your bill payments by setting up a Direct Debit . You stay in control with advance notice of your payments and a choice of payment dates. Visit http://www.thameswater.co.uk

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) 118 959 3333 and destroy and delete the message and any attachments from your system.

For more information on Thames Water visit our web site at http://www.thameswater.co.uk.

Our vision: If customers had a choice, they would choose Thames Water.