Since the water main burst on Barhatch Road, The Cranleigh Civic Society has been investigating water supply capacity and issues within the Cranleigh network.
Since September 2016 there have been further burst drinking water pipes on:
- Avenue Road
- The Ridgeway
- Elmbridge Road and outside Bridge Cottages
- The Common
- Wyphurst Road
- Horsham Road
- Durnsford Way
- Wanborough Lane
- Bloxham Road
Why have all these water pipes burst?
Thames Water say that the big burst water main on Barhatch Road was due to a faulty valve which caused excessive pressure in the water network.
Thames Water has continually highlighted capacity issues in relation to water supply in Cranleigh, in comments against significant planning applications, stating that the existing infrastructure has insufficient capacity to meet the additional demands of the proposed developments approved in Cranleigh.
However, Thames Water seem unable, or perhaps unwilling, to object to any development on the grounds of water supply constraints and state that they have a statutory duty to provide water at a minimum of 1 bar of pressure.
Cranleigh Society is concerned that the recent series of burst pipes indicates that our water system can not cope with the increased pressure required to service the over a thousand houses that Waverley Borough Council has already granted permission for in Cranleigh.
Thames Water confirmed to us that:
“The development of new properties won’t result in an increase of water pressure. We carefully monitor the pressure levels across the five metered areas that cover Cranleigh, and make sure they are in within acceptable tolerance. When new properties are connected, it will increase the amount of water in that section of our network, but the pressure should remain fairly constant.”
Reading between the lines this seems to state that water pressure will increase. And, in our last meeting with Thames Water on Friday 17 February 2017, when pressed for an answer about potential increase in water pressure to accommodate new housing, the answer was that pressure would increase.
Asbestos Cement Pipes
During our investigations about water supply, we have discovered purely by chance, that Cranleigh has ageing asbestos cement (AC) water main pipes. This information was shared with residents by contractors working on the burst water pipes, who were seen wearing masks, and this has now been confirmed by Thames Water.
These pipes were first manufactured in the UK in the late 1920s and became widespread during the 1950s, 1960s and, we understand, the early 1970s. Due to the risk to health following exposure to asbestos, importation, supply and use of all asbestos products have been banned in the UK since 1999.
Residents have raised concerns with us about these pipes and we have tried to find out as much information as we can to share with you.
We spoke to people working on the pipes in Cranleigh and requested further details from Thames Water to ascertain the reason for all the recent bursts, to raise concerns about the ageing AC pipes, some of which are now between 50 to 70 years old, and whether the potential increase in water pressure within the Cranleigh water network, due to significant development, might increase asbestos fibres within the water supply.
Below is a photo of the 6″ AC main in Fettes Road, taken on 29-Sep-16 at 4pm.
We found a report commissioned by the Department for the Environment in 1998, and issued to the Water Industry, mentioning that “Concern has been expressed over the possibility of asbestos fibres being released into the water supply by deteriorating pipework.”
It is also suggested that that the “aggressiveness of the water, and the length and age of the pipes probably contribute to the concentration of fibres found.”
Furthermore, it highlighted that “There is a clear relationship between the use of AC water mains and population density i,e, large rural areas, contain a relatively large proportion of AC water mains“.
You can read a full copy of the report here: Water Industry Report re Asbestos Water Main 1998
On 27 September 2016 Thames Water confirmed to us that:
“Although some types of Asbestos can be hazardous when handled, it is not considered to be hazardous to human health when used in potable water networks and Thames Water have around 792km of Asbestos Cement pipes out of its network of 31,500km water mains. Research available on the Drinking Water Inspectorate (DWI) website provides some clarifications here, stating that:
‘The World Health Organisation considered asbestos in drinking water arising from asbestos cement pipe in their 1993 edition of the Guidelines for Drinking Water Quality. The guidelines state “Although well studied, there has been little convincing evidence of the carcinogenicity of ingested asbestos in epidemiological studies of populations with drinking water supplies containing concentrations of asbestos…There is therefore no consistent evidence that ingested asbestos is hazardous to health and thus it was concluded that there was no need to establish a health-based guideline value for asbestos in drinking water’
NB the above references ingested asbestos and there is no suggestion that asbestos is, or could be entering the customer’s water supply here at any level of concentration.”
We wanted to find out more so we looked at the:
World Health Organisation (WHO) Guidelines
We found out that the WHO Guidelines for Drinking-water Quality FOURTH EDITION discovered no consistent evidence that ingested asbestos is hazardous to health. Although it is recognised that asbestos cement pipes can contribute to fibre levels in drinking water and are hazardous to people cutting the pipes.
This extract is taken from the report, which in the main matched with what we had been told by Thames Water with the exception of the information in the last paragraph (“The primary issue surrounding asbestos-cement pipes is for people working on the outside of the pipes (e.g. cutting pipe), because of the risk of inhalation of asbestos dust.“) :
“Asbestos is introduced into water by the dissolution of asbestos-containing minerals and ores as well as from industrial effluents, atmospheric pollution and asbestos-cement pipes in the distribution system. Exfoliation of asbestos fibres from asbestos-cement pipes is related to the aggressiveness of the water supply. Limited data indicate that exposure to airborne asbestos released from tap water during showers or humidification is negligible.
There is therefore no consistent evidence that ingested asbestos
is hazardous to health, and thus it is concluded that there is no need to establish a health-based guideline value for asbestos in drinking-water. The primary issue surrounding asbestos-cement pipes is for people working on the outside of the pipes (e.g. cutting pipe), because of the risk of inhalation of asbestos dust.”
We have also looked at WHO background information
You can read the full report here:
Asbestos in Drinking-water Background document for development of WHO Guidelines for Drinking-water Quality
However, although WHO has still not issued guidelines for asbestos in drinking water, we found this is not the same in the US, where the Environmental Protection Agency has included asbestos fibres in the National Primary Drinking Water Regulations since 1992.
You can read more about this issue – Drinking Water Quality: Problems and Solutions- By N. F. Gray) .
Looking towards the UK we found a report carried out for the Drinking Water Inspectorate (UK) in May 2002 which concluded that:
Inhaled asbestos is a known human carcinogen and considerable care is required in handling asbestos products, including asbestos cement water pipes, to prevent the inhalation of asbestos fibres. The tumours caused by asbestos are mesotheliomas and are considered to be characteristic of asbestos exposure. The evidence that inhaled asbestos can cause tumours at any other site in the body is, at best, equivocal. However, the evidence with regard to mesotheliomas strongly supports the contention that fibre size and surface characteristics are important in the pathogenicity of asbestos. Fibres greater than 8 mm in length and less than 0.25 mm in diameter are the greatest concern with very short fibres of less than 1 mm considered to be of low risk. Asbestos fibres from drinking water are either in this latter category or are of much greater diameter than those of greatest concern and so the risk to health from inhalation of such fibres is considered to be low.
That asbestos cement pipes can contribute to fibre levels in drinking water is not in doubt but asbestos fibres from natural sources are found in the great majority of waters, whether or not they have passed through asbestos cement pipes. Asbestos in drinking water is not, therefore, solely a function of asbestos cement pipe.
The evidence from epidemiological studies and from laboratory animal feeding studies does not provide support for the view that asbestos from drinking water is of concern. WHO concluded in their 1993 Guidelines for Drinking Water Quality “Although well studied, there has been little convincing evidence of the carcinogenicity of ingested asbestos in epidemiological studies of populations with drinking water supplies containing high concentrations of asbestos. Moreover in extensive studies in laboratory species, asbestos has not consistently increased the incidence of tumours of the gastrointestinal tract. There is therefore no consistent evidence that ingested asbestos is hazardous to health and thus it was concluded that there was no need to establish a health-based guideline value for asbestos in drinking water”.
The WHO Drinking Water Committee did not regard asbestos as necessary for reconsideration in the current phase of the rolling revision.
Asbestos cement pipes have been widely used for drinking water distribution and there are many kilometres to be found all over the world, including many European countries. Few countries still install asbestos cement pipe, primarily because of issues with handling, but there appears to be no concern for the health of consumers receiving the water and there appear to be no programmes to replace asbestos cement pipe for this reason.”
You can read the full report here: dwi70_2_135_asbestos-cement-pipes
The Water Industry Report re Asbestos Water Main 1998 raised the possibility that higher instances of asbestos fibres were present in deteriorating AC pipes and information on the transmigration of ingested asbestos through the gastrointestinal tract to other tissues has been contradictory and inconclusive.
We feel that there should be an ongoing programme to replace all Asbestos Cement pipes with plastic.
However, Thames Water have confirmed that:
” The consensus after studies of the effects of asbestos fibres in drinking water, show there is little evidence of any health concerns. Although some types of Asbestos can be hazardous when handled, it is not considered to be hazardous to human health when used in potable water networks. For this reason there are no plans to replace the current sections of asbestos piping, other than for an operational need.”
They have also confirmed that when pipes do burst and are replaced:
“If we find asbestos pipes when carrying out work, we take extra care to ensure our staff and customers are safe at all times. All pipes will be washed through to avoid the risk of asbestos entering out network.”
When pipes burst, we understand that they are then replaced with new plastic pipes, using an “Aquagrip” connection. However, it appears that old redundant AC pipework remains in the ground. We have concerns that this might expose future road workers to risk when they carry out further groundwork.
We think that the AC pipework should be routinely removed from site when it is no longer in use and treated as special waste.
Thames Water responded as follows to our request for more information about redundant pipework:
“I can answer your question regarding leaving the abandoned pipes in situ.
In accordance with current Environment Agency Guidelines (EA Regulatory Position Statement 008, version 7 “Leaving decommissioned pipe in excavations” issued 2014), intact or damaged asbestos pipes, including sections damaged by pipe bursting, can be abandoned and left in the ground as intact pipes provided that:
i ) any excavated sections or broken pieces of pipe that are not fully contained are removed to a suitably authorised site
ii ) the presence and condition of the asbestos is recorded on corporate records and that information is passed to other utility companies or others in response to pipe location requests.”
Thames Water have confirmed that they intend to start a replacement programme early 2018.