The world faces unprecedented changes in climate and environment, and an increased risk of natural disasters, which for the UK will include floods, droughts and heat waves . Natural disasters, whether hurricanes or floods, potentially pose a risk to drinking water and consequently public health. After Hurricane Ami hit an island of Fiji, nearly 75% of water samples taken showed contamination . Due to scarcity of safe water during large emergencies, high incidences of fever, diarrhoeal illnesses and skin infections are common place, at least in low income countries . Isolation from medical care further increases rates of morbidity and mortality. Where drinking water is still available, albeit not safe to drink (with or without treatment), water advice is issued. Public health communication is key to safe water behaviour and compliance with advice.
Compliance studies have varied in methodology with some focusing on unboiled tap water and others on boiled water, reducing comparability across studies and across notices. With the exception of the Hurricane Rita study , previous studies have focused on human error and everyday incidents, and for the absolute majority of these, the notice investigated is 'Boil Water'. This study is the first to contrast advice recollection, information use, water behaviour and compliance during an incident involving two notices. It is also the first to investigate a 'Do Not Drink' notice issued due to a natural disaster, and the first to include compliance with the general advice to boil bowser water.
It should be noted that the study took place 18 months after the incident. This may have resulted in a lower than normal response rate. Compliance surveys sent out within one month of the incident have yielded response rates around 65% [e.g. ]. However, risk perception studies normally attract response rates just below 20% [e.g. ]. The time delay may also have impacted consumers' recall of actions and events. However, the 2007 Gloucestershire flood incident was unique and highly memorable; our study has shown that consumers' main concern revolved around their tap water; and in focus groups carried out after the postal questionnaire, consumers shared very detailed accounts of the incident and their quest to access safe drinking water. The time lag, nevertheless, does place some restrictions on the results and conclusions presented here.
Consumers relied on a range of sources for information about safe water behaviour, and use of sources differed somewhat between the first and the subsequent three stages, with the exception of local radio which remained the primary source through the whole incident. Information usage was at its highest during the 'Do Not Drink' notice stage. In situations of lots of uncertainty, the public commonly seeks out more information sources .
During natural disasters, water advice has commonly not reached consumers. In the aftermath of Hurricane Rita, as few as 31% of people issued with a 'Boil Water' notice were aware of it . In the present study, 3% of participants reported not receiving any water advice at all when the tap water was returned. In addition, several consumers reported not receiving one of the advices. Due to the nature of the crisis, Severn Trent Water was not able to inform consumers before the water supply failed. Similarly, printed media and media websites were unable to deliver advance warnings. Official water notices were, however, issued during the three subsequent stages. These were consulted by only about 40% of consumers. Notably, older participants and those in paid employment hardly used them. For an information source that did reach all households, a 40% efficacy is very worrying, and it is essential that we evaluate how official advice is provided to the general public; especially since we also found that receiving information from the water company was positively associated with feeling informed. The apparent discrepancy most likely stems, in part, from the fact that the first water notice was not a standard water industry notice; thus, it is therefore essential that standard water industry protocol be upheld in future incidents. This is also the recommendation of the Drinking Water Inspectorate in their Incident Assessment Letter . Another reason may be the close collaboration between Severn Trent Water and local media, which we discuss further below.
As printed information could not be made available when the tap water was turned off, family/friends and direct media such as radio and television featured prominently during the first incident stage. In New South Wales, 67% of people found out about severe storm warnings through television, but during the storm they relied more on radio and family/friends .
Personal dissemination networks have been shown to be particularly vital for vulnerable sub-populations , and interpersonal information is often perceived as more credible and efficient than official information sources [10, 30]. Decisions on how to respond to flood warnings have also been found to rely to some extent on the behaviours and attitudes of people close by . In the present study, we found that family/friends/neighbours were the second most preferred source along with local newspapers (which was significantly used by older consumers) and the water company, despite a drop in use after the initial stage which presumably is due to the availability of printed media from then onwards. Dissemination plans should be revised in order to tap into family/friends/neighbours as a potential information stream, e.g. personal networks and nomination of local 'disaster contact persons' can be established through local community organisations, and dissemination through these networks should be given prominence.
Reflecting the complexity of the event and the combination of two subsequent notices, consumers' advice recollection was noticeably affected, leaving consumers highly uncertain about which notice was in place when, with significant proportions believing two notices were in place at the same time. Clearly, the public is not aware of the exclusive nature of notices (i.e. only one can be in place at a time) or that there are several different types of notices. This could indicate that they construe water as either safe or not safe.
Typically, non-compliance with 'Boil Water' advice ranges between 9% and 20% [11, 32] whereas after Hurricane Rita, only one-third reported boiling water for drinking . If unsafe actions such as using unboiled water for brushing teeth or preparing/cooking food are considered, non-compliance increases dramatically to 57% and 77% for human error and natural disasters, respectively [13, 32]. Our data show high non-compliance for the 'Boil Water' notice (29.3%), and when including other unsafe behaviours, it rises to 48.3%. Comparison of 'Boil Water' compliance for this incident with preliminary results from a recent UK human error 'Boil Water' incident tentatively confirms that natural disasters are associated with higher degrees of non-compliance compared to human error incidents (Knapton, Hunter & Rundblad; submitted 2010).
The first water notice issued was 'Do Not Drink'. To date there is only one previous study of this advice, a human-error incident in Israel in 2001. Non-compliance was estimated to 18% . We found that non-compliance for drinking was significantly higher for the 'Do Not Drink' notice (47.2%) compared to the 'Boil Water' notice (29.3%). Similarly, overall non-compliance was also significantly higher: 62.9% versus 48.3%. By contrasting participants' use of unboiled and boiled tap water, we can see for the first time that the higher use of contaminated water during the 'Do Not Drink' notice stage is due to consumers boiling the water, presumably due to a belief that it renders it safe to drink and use. These results are in line with Rundblad's  hypothetical 'Do Not Drink' scenario study which predicted that 39.3% of consumers would boil and drink contaminated water. In the Mythe incident, there were attempts to neutralise this common folk belief by including additional information on notices and in material supplied to media and the public. It is beyond the scope of this study to evaluate if this addition did impact consumer behaviour; however as the high degree of non-compliance here suggests, this measure alone is far from sufficient. It is highly likely that this folk belief in boiling is linked to the aforementioned binary folk classification of water. The higher degree of non-compliance for 'Do Not Drink' is not because consumers acted differently for the two notices, but rather that the protective measures they took were more or less the same, and as such, they were not sufficient for the more restrictive notice.
It should be noted that many consumers varied in their behaviour such that they displayed a mixture of safe and unsafe behaviours. Some also engaged in over-cautious behaviour such as flushing the toilet with boiled tap water or avoiding to flush. The mixture of risky and over-cautious actions can be attributed to consumers not being aware or being unsure of what actions are unsafe. The title of the notice 'Do Not Drink' is highly misleading as it fails to highlight all ingestion actions listed on the notice ; an alternative title, such as 'External Use Only' could prove more informative. In addition, the Drinking Water Inspectorate were strongly critical of the notice issued by the health authorities because it did not follow water industry standards and the messages were unclear . We also found that 17.6% carried on using temporary water supplies after the tap water had been declared safe, which is similar to the 10% of consumers continuing to boil water after the 'Boil Water' notice was lifted in Willocks and colleagues' study of 2000 hospital employees in the North Thames region, UK, in 1997 . Information and reassurance that water is safe or that certain water actions are safe during a particular notice are as important from a health point of view as informing about unsafe actions. Worries about potential health hazards can cause severe anxiety and, like detection of discolouration and odour in the water, causes increases in reports of symptoms of waterborne illness . It is vital that the titles of notices be reviewed and that the public's classification of water and beliefs about precautionary actions such as boiling be addressed through public health education.
It is important to separate the public's perception of information sources and their behaviour. While media has been found to impact general risk perceptions because these perceptions are impersonal, they do not necessarily impact the personal risk perceptions that would initiate behaviour responses . In the present study, media did not affect consumer behaviour. However, BBC Radio Gloucestershire came to take up a rather unique position. Throughout the incident, it remained the primary information source, both in terms of usage and preference, and its association with feeling informed was approaching significance. BBC Radio Gloucestershire estimates that roughly half the population of Gloucestershire kept up-to-date about the crisis by listening in, and their website saw a 159% increase of users (personal communication). We believe that its apparent success rested on more than radio being easily accessible. Other local mass media was also favoured; notably, local newspapers were positively associated with clarity of advice. This could indicate a need for geographic-specific information . Severn Trent Water followed standard water industry practice and issued frequent and regular bulletins to the local media in parallel to issuing notices. BBC Radio Gloucestershire was quick to broadcast not only about the mains water loss, but also about locations of distribution sites. Users of local radio therefore knew there was no need to buy bottled water. Another important step taken was the broadcasting of the daily press conferences with updates from Severn Trent Water and Gloucestershire Constabulary. Altogether, BBC Radio Gloucestershire was able to establish themselves as a timely and trustworthy information source. Building on the example of BBC Radio Gloucestershire, it is essential that local media be pre-prepared and, during an event, be continuously up-dated to maximise their role in ensuring public safety.
Although a potential key player in public behaviour response, no information source was associated with water behaviour. We did, however, find that those in paid employment were significantly less likely to comply with drinking water advice. Demographic factors such as socioeconomic status have previously been found to influence behaviour during natural disasters [37–39]. In order to ensure appropriate and safe behaviour during natural disasters, public health education needs to reach all income quartiles, at home or at work.
Lack of electricity contributed to non-compliance after Hurricane Rita . In this incident, approximately 20% of our participants were without electricity, but loss of mains electricity occurred at the same time as consumers were without main tap water and only lasted for 24 hours. Consequently, electricity could only have impacted boiling of bowser water. However, compliance with bowser water advice was very high: 88.7% (drinking) and 72.7% (including food preparation, etc.) Bowser advice is more consistent and thus less open to interpretation as it is water industry practice for every bowser to bear a clear permanent 'Boil Water' message at the point where consumers draw water. Even so, whether consumers conceptualised the instruction to boil the water as relating to use of unsterilised collection vessels rather than unsafe bowser water could not be ascertained in the present study.
Whilst bowser water was used, it was not popular for drinking. Instead, bottled water was preferred during both notices. It has been suggested that bowser water and bottled water serve slightly different purposes, with the former to be used for personal hygiene and cooking, and the latter for drinking. However, it was not clear from the study whether consumers understood such a distinction, or whether there is a general distrust in the quality of bowser water. Thus in future incidents, bottled water should be considered a priority over bowser water, where supply, distribution and recycling allows. More than half of consumers bought bottled water even though the Security and Emergency Measures Direction 1998 requires all water companies to provide a minimum of 10 litres of water per person per day in case of supply failure . We trace buying of bottled water to the public not being aware of this provision duty, especially since consumers who found out about the water loss beforehand tended to refrain from buying bottled water. It is also possible that consumers did not trust the water company to supply enough water and in time.