Equal or unequal pressure plumbing?

G'day
Quick query please. How can you tell if you have equal or unequal pressure? I see it referred to while sourcing mixer taps for a reno. Is it simply, that when you turn on the hot and cold taps, the pressure varies from the hot supply to the cold supply so you get more flow from the cold tap than the hot?
Secondly, how do you know your water pressure? Is there a standard for mains cold and HWT supplied hot? I am in the north-eastern suburbs of Melbourne if that also has anything to do with it?
Cheers
Max

i think I undestand what you mean? If i do then the equal /un-equal thing will vary from house to house depending on your system and set up.

To answer each point in turn:

- If the hot tap runs faster than the cold tap and you have a pipe protruding from the roof, you have an unequal low pressure system. Where both hot and cold taps give out equal low volume water, your system works on equal low pressure. Mains pressure on the other hand is the water system most new homes have and it is ideal because it delivers equal and high water pressure combined. The widely known benefit of this

system is that other amenities can be used at the same time, such as showering and flushing the toilet without effecting the water supply or pressure.

- The water pressure at your particular home will depend on the elevation of your home and your proximity to the reservoir which serves your home. The closer you are to the elevation of the reservoir serving you, the lower your pressure will be. Similarly, the lower your home is in relation to the reservoir, the higher your water pressure.

- The Aussie standard for plumbing I believe is AS3500.

Basically what they're trying to say is that a mixer is useless if you have a gravity fed hot water system, or any other kind of system that works off a break tank. You will almost always lose pressure and flow rates throught the hot water service due to valves and pipe sizing but in a mains pressure application it isnt enough to worry a mixer. If you want to check what pressure you have, you can go to reece and buy a 'hose cock pressure guage' which simply screws on to your hose tap and costs less than $20.

Thanks all for your replies. The Reece pressure thingy sounds like it might be the go. Interesting to know what my mains pressure is.
Cheers
Max