Is Bottled Drinking Water Quality Suitable for Patient Consumption?

The provision of bottled water for patient consumption and assessment of the microbial risk remains a blind spot for infection prevention teams and water safety groups.  Few consider that bottled water could be a source of Pseudomonas aeruginosa or other waterborne pathogens.

There are times when bottled water could be safer and a logistically favourable option for provision of drinking water rather than from the municipal water supplied tap.  However, when assessing the considerable evidence within published literature, those times are likely infrequent and typically linked to emergency situations affecting the municipal supply quality such as flooding, “boil water” notices, unexpected supply outage, burst water mains, etc. 

Bacterial Growth in Bottled Waters

Microbiological quality is particularly relevant when assessing bottled water suitability for patient consumption, yet it remains common for patients, even those with low immune competency,  to have access to and/or be provided with commercial bottled water.

Bacteria may reproduce significantly in the bottle after the bottling process, especially during periods of non-refrigerated storage, transport and on exposure to sunlight.  Bacteria detected in bottled drinking water have been linked to outbreaks. 

It has been recommended not to provide immunocompromised individuals with bottled water due to microbiological findings, however other concerns including chemical and environmental contaminants may also be relevant – particularly for long term consumption which could result in cumulative health effects.

Increasing Trend in Bottled Water Consumption

There has been increasing consumption of bottled water over recent years as consumers are encouraged to drink more for their health and hydration.  Marketing descriptive such as “Pure,” “Natural” and “Fortified” reassure the purchaser of their favourite brand’s virtuous qualities.  What do these words really mean?  It is important to realise that “Pure” does not mean microorganism-free. 

Our municipal drinking water supply is considered “wholesome” and is typically well monitored, tested and released after meeting stringent requirements.  Once over the threshold of a building however, drinking water quality may decline due to multiple factors such as contact with inappropriate materials, the size and complexity of the water system, long pipe runs, stagnancy, poor temperature control, inappropriate user behaviour etc.  Therefore water quality at the tap may be variable depending on its environment and management in those last few meters of pipework. 

Many studies have looked at contamination within drinking water at the municipal source, at the tap, and within different types of bottled drinking waters.  Bottled waters are often found lacking in comparison with the municipal supply.

Understanding the Contaminant Risk from Bottled Water

In 2020, investigators from the United States Geological Survey, Food and Drug Administration, Environmental Protection Agency and National Institute of Environmental Health Science examined the inorganic, organic and microbial contaminants in a selection of individual serving bottled waters from 30 different brands commonly available in the United States.   This study was undertaken to gain better understanding of contaminant risk to human health from bottled water, and has been reported in December 2022 by Bradley et al.,in the Environment International journal.

A variety of water source locations (e.g. US and imported, spring and purified tap water), different treatments and packaging materials (e.g. glass, plastic, aluminium, carton) were assessed.  The authors reported the presence of regulated and unregulated organic and inorganic chemicals, plus microorganisms were routinely detected in the bottled waters investigated – 2 or more detections of potential human-health concern often observed per sample”.   

Arsenic and uranium were frequently detected in spring-sourced bottled waters at 87% and 74% respectively, with excess nitrate in 22%.  Most frequently detected organics were chlorine disinfectant by-products, which were mainly found in purified bottled water but also in some spring and a range of volatile organic compounds (VOC) were found in both.  Pesticides were infrequently found, although one brand had levels more than double the International Bottle Water Association Code of Practice.

At least one opportunistic waterborne pathogen was detected in 80% (24/30) bottled waters studied.  There is considerable variability in contaminant levels, but the purchaser is certainly getting more that they thought within the bottle. 

Patient Exposure Risk Considerations

Multiple publications confirm that market driven perceptions of bottled water as being “better” than tap water are not supported in the literature. 

What is the safe level of exposure for our vulnerable patient populations?  It is likely that the risk of exposure is significantly less in most municipal supplied drinking waters, however, comparable data is needed in order to make effective consumer risk based decision making. There appears a ranking of microbiological risk from

  • spring source bottled water (highest) to
  • bottled purified tap water to
  • municipal supplied drinking water at the tap,
  • to boiled and cooled water and finally
  • bottled sterile water (lowest)

To support Water Safety Groups and Infection Prevention Teams to review and assess the appropriate provision of drinking water in their healthcare populations, and to highlight the hazards that bottled drinking waters pose, the below summary of key publications from the last 15 years helps formulate emergency drinking water plans for when something catastrophic has happened to the municipal tap water supply.

Bottled Water Chemical and Biological Contamination:

Author & DateSummary
Nabizaden et al., 2022Ranked 71 bottled water brands by their level of carcinogenic chemical compounds followed by their bacteriological levels
Angnunavuri et al., 2022The mean lifetime cancer risk was calculated from 600 sachet and bottled waters sampled from two “high end” brands.   The presence of phthalates and pathogenic bacteria were found to be at levels requiring risk mitigation
Tran et al., 2022Pseudomonas aeruginosa detected in bottled water samples by molecular detection method
Brumfield et al., 2020Molecular and culture analysis of different brands of bottled water including sparkling natural mineral water in glass bottles, non-mineral spring water in plastic bottles, artesian water in plastic bottles, reprocessed tap water in plastic bottles.  Different microbial populations and abundancies were present.  The majority in sparkling natural mineral water was Betaproteobacteria, with Burkholderiales being dominant, whereas in non-mineral bottled water Gammaproteobacteria was in the majority with Alteromonadales and Enterobacteriales dominant.  Propionibacterium were present in both types.  These waters were not considered appropriate for vulnerable patients.
Tischner et al., 2021Bottled Water Dispensers (large communal single bottles positioned above a chiller and dispensing tap) were analysed, and fungi detected in 86% of samples with more than half heavily contaminated.  Proliferation occurs in the bottle and then dispensed. As with most opportunistic pathogens, the authors concluded that the risk to populations of “sensitive age groups, patients with immunodeficient conditions, cystic fibrosis, patients with oral lesions plus may also pose a risk to visitors to healthcare institutions”
Cerna-Cortes et al., 2019111 samples from bottled waters analysed: 62% and 29% positive for total coliforms and faecal coliforms respectively, plus 29% positive for fast-growing Non-Tuberculous Mycobacteria.  “Most of the purified bottled water samples analysed in the study had unsatisfactory microbiological quality”
Caskey et al., 2018Pseudomonas aeruginosa detected in 3% of bottled natural mineral water destined for supply to patients with cystic fibrosis

Waterborne Pathogen Outbreaks from Bottled Water Sources:

Author & DateSummary
Guix et al., 2020Bottled mineral water the source of a norovirus outbreak in Spain
Wang et al., 2012Bottled water the source of an Escherichia coli gastroenteritis outbreak amongst university students in China.  Drinking boiled water was inversely associated with being a case
Lai et al., 2011The top 7 risk factors associated with gastroenteritis outbreaks in Taipei: taking antacidsother members of the household being infectedattending a banquet/buffeteating outdrinking bottled batereating honey peacheseating oysters
Naze et al., 2010Pseudomonas aeruginosa outbreak linked to use of bottled mineral water in a Neonatal Intensive Care Unit in France
Eckmanns et al., 2008An outbreak of hospital-acquired Pseudomonas aeruginosa infections in six Intensive Care Units within a German University Hospital which was sourced to contaminated bottled water

Beware good intentions of providing a refreshing “Pure” and “Natural” drink for your patients and ensure your water policy and water safety plan has strict guidance on when bottled water is appropriate for which patient use.  Do not use it as standard or to ease logistics unless you have taken steps to risk assess this approach and assured the microbiological quality of each batch of bottled water intended for patient use as a minimum.

What events would you consider bottled drinking water would replace tap water for patient supply?  How do you restrict inappropriate water quality from reaching your patients?  We hope this Blog will help you in assessing and understanding if bottled water is appropriate for use with your patient groups, if you would like to discuss this information further, please contact us at


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