In Sydney...Why does hot water come out of the tap looking cloudy & dirty ?

Tap water, both hot and cold, contains dissolved atmospheric gasses. But the ability of water to maintain those gasses in solution decreases as the temperature of the water increases. The hot water is still able to contain those gasses as long as the water is under pressure in your plumbing system. But as soon as it exits your faucet and the pressure suddenly drops to atmospheric pressure, the gasses are forced to precipitate. The happens so suddenly that extremely small bubbles are formed, almost too tiny for the naked eye to see. These are what give the water a cloudy appearance. (Harp)

I would continue using the hot water. Adding a little salt to water can lower the boiling point of water as well. But idt it will make a significantly obvious difference.

The water in my sinks comes out looking cloudy as well; its no biggy your water is fine.

you may need to replace the water heater. let me ask this question--- does it only happen for a very short time when you turn on the hot water then stops or is cloudy and yellow for a long time?? if it's just for a short time then you need to replace the nipple that holds the tub spout on with a brass one and this will solve the problem------but if it's for a long time then you need to repalce the water heater You may have hard water and this will form a scale on the inside of the wtr htr. Hard water means there is alot of minerials in the water( nothing you can do about this) and when heated it will cling to the insides of the wtr htr. replaceing the wtr htr will slove this. And when you do keep the wtr htr and cut it open to see what I"m talking about.........good luck

You say cloudy and dirty, if it is just cloudy, it should clear up as you look at it, it is only water vapour locked up under pressure, as explained by the previous answer. If it is dirty, as in a reddish brown colour, then you have rust in your pipes and they need replacing. In some water coolers you get the same effect from pressurisation even in cold water.

Very hot water anywhere comes out of the tap really cloudy. The less hot water is clear. If it is dirty, then I suggest your tank is dirty.