It appears that there is quite a lot of renovating going on and I would like to clarify that power, water, gas etc services have different colours to identify them. It is extremely important to install services in their respective colours, not only for legalities, but mainly for safety.
I won't list all the colours, but these will be some you will probably see.
Orange - Electrical (underground)
Light Grey - Electrical (above ground)
White - Communications
Yellow - Gas
Blue - Water
Red - Fire
Purple - Recycled water
Tan - Garden drip
Now you are probably going to say 'but retic poly pipe is white'. Yes it is, but it is clearly marked for this purpose and it won't ruin your day if you hit it.
This is in accordance with Australian Standard AS-1345.1995.
Thanks, I found this very useful, I have often wondered why all homes don't have the services marked on plan/ drawing which is placed somewhere (meter box perphaps) that stays with that home for reference, it is time comsuming trying to work out where everything runs!