Results Guidance

Help and information on interpreting your water sampling results

The following information is designed to help you understand and interpret the results certificate you have received. Below you will find information on the parameters that water samples are analysed against, which are reflected in results certificates.

Results from microbiology samples (bacteria analysis) are aligned to EU Bathing Water Directive standards (2006/7/EC). British Triathlon events are also measured against this standard, however, the BTF requirement is that the ‘Excellent’ threshold is met. Blue Green Algae results (Cyanobacteria) are aligned to World Health Organisation (WHO) guidance values for the presence of Blue Green Algae in water being used for recreational purposes. The tables below show the relevant thresholds for one off or occasional testing.

EC Bathing Water Directive 2006/7/EC - Inland Waters (Micro-biology testing)

Inland Waters 
Rating: Excellent Good Sufficient Poor (Fail)
Escherichia coli (cfu/100ml) <500 <1000 <900 >900
Intestinal Enterococci (cfu/100ml) <200 <400 <330 >330

*To meet BTF (British Triathlon Federation) requirements, Water Quality results must be rated ‘Excellent’.

EC Bathing Water Directive 2006/7/EC - Coastal Waters (Micro-biology testing)
Coastal Waters
Rating: Excellent Good Sufficient Poor (Fail)
Escherichia coli (cfu/100ml) <250 <500 <500 >500
Intestinal Enterococci (cfu/100ml) <100 <200 <185 >185
Blue-Green Algae Thresholds
Blue-Green Algae Thresholds
Rating: Relatively Low Moderate  High (Fail)
No. Cell/ml <20,000 >20,000 to <100,000 >100,000

*World Health Organisation guidance values for health protection where blue green algae are present, is based on three categories – Relatively Low, Moderate and High, as seen in table above. Swimming is discouraged at moderate level, and prohibited at high level.

Frequently Asked Questions

What should I do if my results fail?

Understanding why your results may have failed, is the first important step. Then determining if the failure is due to an external factor (e.g. recent heavy rainfall, local sewage release) or just the naturally occurring bacteria levels in your water body is key.

 The second consideration is why you are testing. If it’s precautionary or for monitoring/analysis then you may not need to take any further action. If you are testing to confirm the water is safe for use prior to an event or activity, then it may be more complex, and you may have to consider re-testing or changes to your planned activity.

Can the water body be used if test fails?

We can’t advise specifically as to whether you can proceed with your planned event or activity if your water tests have failed, however, as outlined above, understanding why it may have failed is the first important step.

 We are happy to discuss this with you, and offer advice on options that may be available to you, however, we are unable to state whether you can or should proceed with your planned event or activities, as this will be down to your own risk assessment.

How long is the results certificate valid for?

There is no set date on test validity. Technically, the certificate shows the results for the day that the samples were taken. Bacterial levels within water bodies can change quickly, and so no validity on results can be provided.

 However, it’s generally recognised that, due to the turnaround timescales for microbiology (bacteria) results, tests taken a week to 10 days prior to an activity would be acceptable, providing there have been no significant external factors that may impact the water quality in that time (e.g. very heavy rainfall or local sewage release).

 Visible changes to levels of Blue Green Algae present in a water body, following testing, should also be treated with caution.

What is the difference between the EC2006/76 & EC76 Standards?

The 2006 EU Bathing Water Directive came into force in March 2006 and replaced the existing Bathing Water Directive (76/1160/EEC).

The 2006 directive introduced a new classification system with more stringent water quality standards. The water quality standards for the 2006 classifications are much higher than those of the original bathing waters directive.

 We continue to report the 76 Bathing Water standards on certificates for historical analysis, but these can be removed upon request.

What are the EU Bathing Water standards?

The European Union’s revised Bathing Water Directive (2006/7/EC) came into force in March 2006 and replaces the current Bathing Water Directive (76/1160/EEC).

 The overall objective of the revised directive is the protection of public health, but it also offers an opportunity to improve management practices at bathing waters and to standardise the information offered to bathers across Europe.

 The directive introduced a new classification system with more stringent water quality standards and puts an emphasis on providing information to the public.

 Since 2015, bathing waters were classed as either, excellent, good, sufficient or poor. The water quality standards for the new classifications are much higher than those of the original bathing waters directive.

 Water being used for recreational activities and events, within the UK, are generally measured against the EU Bathing Water standards to confirm their suitability.