Environment and Waste

Understanding your Drinking Water

Drinking WaterAs with all water supplies, Gosford's drinking water contains small amounts of naturally occurring minerals such as calcium, magnesium, iron and manganese.

Without these substances the water would taste bland; however, they can impact water quality when a change in demand or temperature occurs.

Most of the water quality concerns reported by customers to council are related to its appearance, taste and/or odour.

Council conducts regular testing on aesthetic and health criteria to ensure the water meets the Australian Drinking Water Guidelines and is safe for human consumption. 


Although town drinking water supplies are generally colourless, from time to time the water's colour can change.

Sometimes it can take on a yellow or reddish/brown tint to almost being black, while at other times it can appear milky white or blue - this is known as discoloured water. 

The Discoloured Water Fact Sheet contains more information.  

Taste and odour

The taste and odour of water can vary from tap to tap and can be impacted by naturally occurring minerals, council treatment processes and internal plumbing. An individual’s personal likes and dislikes can also influence their perception of taste and odour.
Some of the most common taste and odour complaints are listed below.

Chlorine taste and/or smell

Council adds chlorine to the water supply at its water filtration plant to remove harmful bacteria and protect water quality. A small residual of chlorine is generally present in the drinking water coming from your taps and, from time to time, a slight chlorine taste or smell may be present. Council carefully controls and monitors this process to ensure the residual poses no risk to health.

Seasonal changes in demand, the distance from the water filtration plant and unavoidable changes to system operation can impact the degree of chlorine in your water.

The taste and smell of chlorine can be eliminated by placing some water in a covered jug in the refrigerator. It is recommended this water be consumed within 24 hours. Domestic water filters or jug filters are also useful.

Musty, mouldy or earthy tastes or odours

Musty tastes and odours in drinking water can be caused by organic growth within water pipes. Mould and bacteria can breed in internal plumbing when certain jointing compounds are used for domestic fittings or appliances, or when cold water pipes pass closely to hot water pipes that are not insulated.

Water pipes in areas of the supply system with low flow rates can also create an environment for organic growth.

Rusty or metallic taste

Drinking water with a rusty or metallic taste generally contains excessive iron, manganese and/or other metals. When these materials are present in high levels, there will also be a change in the colour of the water—this is known as discoloured water.  The Discoloured Water Fact Sheet has more information.

Council has thorough treatment processes to remove naturally occurring iron and manganese from the water supply. However, as the water moves through the system to your tap, it may pick up material from corroding pipes not lined with cement that may change the taste of the water.

A rusty or metallic taste may also be noticed if internal pipes are corroded. When a house’s plumbing is corroded, the water may appear clear at first, but then turn rusty or black in a few minutes.

Rotten egg smell or taste

A rotten egg smell and/or taste in water indicates it most likely contains hydrogen sulfide gas. This is typically caused by decay of organic matter or chemical reactions in the plumbing, or bacteria which change naturally occurring sulfates into hydrogen sulfide. These bacteria can be present in the water supply system, groundwater or hot water systems.

If the smell only comes from a hot water tap, there may be a problem with the hot water system. However, if the smell is strong from both the hot and cold water taps when they are first turned on and diminishes after the water has run, the bacteria is probably in the water supply system.


The taste and smell of drinking water does not change as a result of water fluoridation because the type of Fluoride used to fluoridate the water supply has no taste or smell.

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