Beach Water Quality

Introduction

Waitakere's beautiful and clean beaches are one reason we live and visit here. We want to keep them that way. Which is why we test the water quality at our most popular beaches and swimming spots every week over summer.

Council conducts its testing program in accordance with the latest Ministry of Health and Ministry for the Environment guidelines.  

Testing takes place every week between 1 November and 31 March the following year (the bathing season), and on a monthly basis outside that period. This page is updated, as soon as the most recent test results are available.

Water Quality Results

Water quality results for Waitakere City Beaches and other outdoor swimming spots. Warning Signs are not erected when the guidelines are exceeded during the non-bathing season (April - October).

Lagoon Results (Freshwater) - results are E.coli/100ml

Guidelines for beach water tests

The guidelines used by the Council are the Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas published by the Ministry for the Environment and the Ministry of Health in 2002. These guidelines aim to establish national consistency in recreational water quality and public awareness of when there is a health risk. 

Why test beach water?
We want to be sure that the water at our most popular swimming beaches meets national guidelines. We also want to know if there are any changes to water quality around Waitakere's coastline.  We also believe it's important for people wanting to swim or participate in water activities to have access to information about beach water quality.

What happens if the guidelines are exceeded?
If the results exceed the single sample maximum of the Ministry for the Environment guidelines, Council will erect beach warning signs advising the public not to swim. These signs will only be withdrawn when subsequent test results show that the levels have dropped below the minimum acceptable level of the guidelines. 

For further information see the following websites:

Ministry for the Environment
Ministry of Health

Health impacts of contaminated recreational water

There are a number of disease-causing bugs (called pathogens) that once discharged into the marine environment can survive for some time. Every time we come into contact with seawater that has been contaminated with human and animal faeces, we expose ourselves to these bugs and risk getting sick. Pristine marine waters are unlikely to present a health risk from these pathogens. 

What does 'risk' mean?

The risk is of getting sick when swimming, surfing or otherwise being exposed to the seawater. The guidelines that New Zealand councils use are based on a fixed level of risk, which in turn is based on overseas guidelines (which have been confirmed by New Zealand studies). Overseas investigations have settled on a maximum acceptable level of risk of 19 in every 1000 bathers contracting an illness. 

Even when beaches meet the guidelines there will still be a health risk associated with recreational activities in the sea. Because scientists are not directly measuring the pathogens, it is not possible to say there is zero risk to public health, especially where there are known inputs of human and animal faeces. 

If tested waters exceed the acceptable level of risk, the public is advised that the area is unsuitable for recreational activities. 

What does 'illness' refer to?

Illnesses related to contact with marine waters were initially thought to be confined to gastrointestinal illness such as salmonellosis. More recently Giardia, Campylobacter and Cryptosporidium have also been shown to cause gastrointestinal illness. These pathogens cause diarrhoea and sometimes vomiting associated with 'tummy bug' symptoms. Recent studies indicate that respiratory illnesses, such as those that cause cold and flu-like symptoms, can also result from swimming in sewage-contaminated water. Skin, eye and ear infections can also be caught through contact with marine water. Illnesses related to toxic substances - such as heavy metals or PCBs - are not measurable with indicator bacteria.

Risk factors

Stormwater, and treated and untreated sewage discharged directly into our oceans and harbours, can contain a variety of micro-organisms that can cause disease. Therefore there may be a greater risk of getting sick under certain conditions, such as: 

• two to three days after rainfall
• during full immersion in seawater that may be contaminated with sewage or run-off 
• high exposure to shallow water where there may be higher concentrations of pathogens. 
• There may also be a greater risk to those with reduced immunity, the elderly and the very young. 

The bugs

In New Zealand we are becoming increasingly aware of the potential health risks associated with swimming (and other related activities) in marine waters. Although this problem is not as severe as in many other countries, it is important that we manage the problem in the interests of public health.

When monitoring water quality at New Zealand beaches, water managers and scientists are interested in the number of disease-causing pathogens present. It is impractical to measure the pathogens directly, so indicator bacteria are used to alert water managers to possible health risks presented by the pathogens. 

What are indicator bacteria?

In the case of the recreational water-quality guidelines the indicator bacteria are enterococci and Escherichia coli. These bacteria occur naturally in the gut of humans and animals, including mammals, birds, fish and reptiles. Enterococci themselves do not pose a significant risk to human health. Rather, they indicate the presence of faecal material, which contains disease-causing pathogens. It is the number of enterococci per 100ml of water that is measured and on which the guideline levels are based. 

Sources of contamination in waters used for recreation

Sewage 
Sewage from many communities is collected via a network of pipes and pumped to a central facility, where it is treated before being discharged to the environment. Sewage consists mostly of water, but also contains organic material and micro-organisms. There are a number of factors that can cause sewage to enter the environment before completing its journey through the treatment facility. The main ones include: 

• Broken or leaky pipes - these can be caused by ageing pipes, construction activities or road works 
• Overflows, during heavy rainfall - the treatment facility may not be able to cope with the volumes of water and sewage entering the system, so pumps are turned off and sewage is discharged directly to the environment. This is made worse where houses have stormwater illegally connected to waste water. Also, some older sewerage systems do not have completely separated sewage and stormwater pipes. During high rainfall, stormwater (urban run-off) can enter the sewerage system and cause sewage to overflow into the stormwater pipes. Sewage is then discharged directly to the environment
• Emergency overflows - these can also occur periodically during maintenance of sewerage systems. 

There are also other sources of sewage:

• Some older properties, especially baches, are still connected to a septic tank. Where these have deteriorated they leak contaminated water into the groundwater system. This contaminated water then ends up at the beach. 
• Some boaties discharge their waste directly into the sea, without treatment. The Ministry for the Environment's booklet, Dealing with sewage safely and responsibly on your boat, deals with discharges from all marine vessels. 

The cost of upgrading much of the country's ageing pipes to cope with our increasing population is estimated to be several billion dollars. It is anticipated that these upgrades will have to be spread over several decades. 

Stormwater 
Rainwater collected from roofs, driveways, roads, car parks and other sealed surfaces is piped directly to rivers, lakes and the marine environment without treatment. During its travels stormwater collects a number of nasties along the way. This includes waste from domestic animals, which collects on footpaths, gutters and lawns. This contaminated water is washed into the stormwater system during rainfall and ultimately ends up on our beaches. Animal waste collected in stormwater contains disease-causing organisms that can affect human health. These pathogens can cause colds, flu, respiratory illness, gastrointestinal illness and skin, eye and ear infections. 

Rural run-off 
Farm run-off, especially that from dairy farms, can add significantly to the contamination of waterways. Apart from farm oxidation ponds that have been shown to contain high levels of bacteria and pathogens, a large amount of animal waste ends up on the paddock. Depending on a number of factors – including distance to the nearest stream, rainfall intensity and stock numbers - faecal material ends up in waterways, which ultimately discharge to the sea. Where stock have access to streams and rivers for drinking water, excrement may be deposited directly into the water.