Thames Water Responds to Questions and Says 90% of Affected Homes Now With Water

Published on: 7 Nov, 2023
Updated on: 10 Nov, 2023

By Martin Giles

Thames Water has now responded to questions posed by The Guildford Dragon on the water supply issue that has been affecting homes in Guildford and Waverley boroughs. They say that 90% of affected properties are now with a water supply.

But a message from Guildford Borough Council claims: “The fault at Shalford Water Treatment Plant has been fixed and all customers should now be back in supply.”

GBC message regarding water supply

And a note from the leader of Waverley Borough Council, Paul Follows, to the joint CEO of Waverley and Guildford Councils, shared with The Dragon, states: “As per my note to you regarding your meeting later with TW and SCC. – I believe the idea that ‘only 11 properties’ remaining impacted is not just wrong, but patently ridiculous.

Cllr Paul Follows

“I see a post from the MP at 5pm stating 1300 still impacted. How did this go from 1300 to 11 in that short space of time? Can you ask TW what the basis for this statement is?

Please note the following ENTIRE ROADS that remain without water within Waverley [roads in Guildford were also listed].”

Here are the questions sent to Thames Water and their responses:

What was the damage caused by storm Ciaran at the Shalford Water Treatment Plant?

Storm Ciaran caused power outages at two of our water treatment works; towards the end of last week.
Shalford experienced technical problems as a result of Storm Ciaran.

How many customers/ premises are affected in total? How many homes in Guildford Borough are affected? Can you break down the total number by postcode?

Over the weekend around 13,000 properties were impacted.
Now around 90 per cent of properties are back in supply
Homes in GU1, GU2, GU3, GU5, GU6, GU7, GU8 were impacted.

Why are some homes affected even though others nearby are not? (Is there a map showing where homes get their supply from?)

Pressure needed to build in our pipe system as water returned – resulting in water returning to customers at different times.
We cannot supply a map.

If a power outage caused the problem at the Shalford Plant why was there no backup power supply? Why was the system so vulnerable, especially as there have been two similar incidents in the last 12 months (in April (see: Low Water Pressure Reported in Guildford) and in November 2022 (see: Thames Water to ‘Work Through the Night’ to Fix Guildford’s Water Supply)).

A power outage did not cause the issue at Shalford it was a technical issue resulting from Storm Ciaran.

Are the sewage discharges that have occurred upstream at Cranleigh and Haslemere in any way connected with the incident?

No – sewage discharges are not connected to this incident.
As you’re aware the Met Office issued weather warnings across the country last week due to Storm Ciaran and many regions are experiencing heavy rainfall. We maintain over 68,000 miles of sewers across our network. At times of heavy or continued rainfall, the sewer system can’t always cope with the extra volume. Storm overflows are used to prevent sewers flooding our homes, gardens and streets. They act as a safety valve, diverting some of the rainwater and foul water into watercourses.
We call this mixture ‘storm discharge’. Although it does contain some untreated sewage, storm discharge is heavily diluted because it’s mostly rainwater. Heavy rainfall can have an instant impact on our sewer systems but larger catchments can have a slower response. This means there can be a delay between it raining and the flow arriving at the overflow point.
Regarding the recent storm overflow data from our EDM map, just to flag that our monitors indicate:
- that overflows are currently discharging into a watercourse;
- the date and time of the last recorded discharge;
- The data received from our EDM monitors isn’t always accurate. It doesn’t confirm discharges, it only indicates them. We’re being open and sharing that data exactly as we receive it, so customers can make more informed decisions.
- The data is verified by our EDM and monitoring teams and is published in the EA’s annual storm overflows data which we also publish on our website: https://www.thameswater.co.uk/about-us/performance/river-health/storm-discharge-data