Potential health hazards vary depending on the water type and activity. In general the more contact with the water the better the water quality must be. The guidelines define physical, chemical and microbiological limits on water quality for three main categories of recreational activity:
- Primary Contact recreation - where the body can be fully immersed and there is the potential to swallow water, and you are in direct contact with the water. This includes surfing, water skiing, diving and swimming.
- Secondary Contact recreation - includes activities such as paddling, wading, boating and fishing in which there is direct contact but the chance of swallowing water is unlikely.
- Passive recreation - is where there is no contact with the water and includes scenic appreciation, walking and picnicking around the water.
Hazards include accidents; exposure to the elements; microbiological pollution; chemical pollution and exposure to toxic algae and their products. The contamination of recreational waters can result in disease outbreaks and illness in the community. The greatest potential risk is posed by microbial contamination of the waters by such organisms as bacteria, viruses and algae. This is why NSW Health recommends that you do not swim within 24 hours of heavy rain at ocean beaches and within 3 days in estuaries or rivers.