Beach water testing: frequently asked questions

Public Health Sudbury & Districts tests public beaches regularly to protect swimmers from getting sick due to bacteria in the water.

We test designated public beaches throughout the summer to protect swimmers from potential illnesses that could be picked up from unacceptably high levels of pathogenic organisms in the water and post the results online. For inspection information, visit Check Before You Go!.

Why are our public beaches tested?

All open bodies of water contain some infectious agents such as bacteria, viruses and other organisms. These organisms are usually at a low level and pose little risk to swimmers. However, factors such as temperature, rainfall, waterfowl and even swimmers themselves can cause the level of infectious agents to rise to where they might pose a health risk to the public.

Therefore, we test designated public beaches throughout the summer to protect swimmers from potential illnesses that could be picked up from unacceptably high levels of these organisms in the water and post the results on Check Before You Go!.

What is a designated public beach?

A designated beach is one that is owned and operated by the municipality which the general public has access to. There are currently 35 designated beaches in the Sudbury and Manitoulin districts.

Public Health Sudbury & Districts may also monitor any other bathing area, except provincial parks, to which the public has access, and where there is reason to believe that recreational use of the water may result in water-borne illness or injury. Public Health Sudbury & Districts is not responsible for routine monitoring of private residential beaches that are neither used by, nor accessible to, the public at large.

How often are beaches sampled?

Every designated public beach in our service area is sampled weekly in June, July and August. They may be sampled more frequently depending on the circumstances.

What is analyzed in beach water samples?

The public health laboratory analyzes each water sample for E. coli bacteria, which is an indicator of fecal pollution. The sample results indicate the quality of the beach water at the specific time samples were taken. In order to obtain a representative assessment of the water quality, a number of samples are taken across the beach.

What does it mean when a beach is unsafe for swimming?

The term “unsafe” means the Medical Officer of Health is advising the public against swimming in the water because unacceptably high levels of bacteria, or the presence of a blue-green algae bloom, may pose a health risk. In these situations, warning signs are posted at the beach. Swimmers still have the option to swim if they choose, but do so at their own risk.

Public Health Sudbury & Districts removes the warning signs when bacteria levels in the water return to acceptable levels or, in the case of a blue-green algae sighting, the sign is removed at the end of the bathing season. This is because blooms are not anchored and can move from one location to another. New blooms can also form.

When is a beach considered unsafe?

A beach is considered unsafe when bacteria levels are above acceptable provincial levels for bathing beaches.

Before a beach is posted, results from several samples are required. The geometric mean (a type of average) is calculated. When the geometric mean of the sampling results exceeds 200 E. coli bacteria per 100 ml of water, Public Health will resample the water. The number of water samples taken from the beach will be doubled and analyzed. If the geometric mean of these samples exceeds the 200 bacteria per 100 ml, Public Health Sudbury & Districts will post signs on the beach warning swimmers to stay out of the water.

What are the risks of going into the water when warning signs are posted?

Going into water with elevated levels of E. coli puts bathers at risk for skin, eye and nose infections. Stomach disorders can also occur. Illness can occur if swimmers swallow beach water, if water gets into their ears, eyes or nose or if it comes in contact with open wounds.

Ingesting high levels of blue-green algae toxins can cause liver and nervous system damage. The algae toxins can irritate a person’s skin and, if ingested, cause diarrhea and vomiting.

What factors affect pollution at our beaches?

Many sources of water pollution can result in beach postings. These include:

What can I do to help keep beaches safe?

This item was last modified on July 16, 2018