Once such a code is AS3500 National Plumbing and Drainage Code since the early 80's. Many utilities have introduced a backflow program many have nominated for a policy of containment, which ensures the integrity of their water supply, but what happens elsewhere? In the workplace, the club anywhere that you can access potable water.

Do you know if there is a possibility of contamination of the water supply, do the workplace or club management know, well in many cases probably not can it be serious? Worst case scenario death least case unpleasant tasting water. How many people have had upset stomachs or vomiting? Do you know what caused it? Generally the kebab, hamburger or Chinese takeaway get the blame.

Although authorities have adopted backflow programs there is still a general lack of awareness regarding backflow, with statements being made by utilities as to wether we believe the risk to be minimal. How do they know when no real studies have been carried out in Australia and there have been very few cross connection instances documented again probably due to the lack of awareness authorities not wishing to draw attention to the situation.

In the USA, where backflow device have been utilised and indeed developed for many years it has become a key focus to the extent where cross connection instances are documented there are central registers of annual test compliance for high and medium hazard devices.

One of the most simple examples of a cross connection is topping up the backyard swimming pool, throw the hose in the pool and turn the tap on, then a couple of street away the water main bursts, which creates a negative pressure, which then starts sucking the water out of the pool back into the water main, although you may consider in many cases pool water to be OK. How do you really know?

Another simple one is liquid fertilisers that you plug on the hose whilst watering the garden, what happens if there is a negative pressure?

As there is little documentation in Australia I will briefly give you an idea of incidents that have occured and documented in America.

1.  Human blood in the water system.
    Cause:- Hydraulic aspirator in a funeral home
2.  Burned in the shower
    Cause:- Mains break causing back siphonage from a chemical storage facility
3.  Propane gas in the water main
    Cause:- Purging a propane gas tank prior to repair using water from a hydrant. The residual propane pressure was higher than the mains pressure.
    Result:- Hundreds evacuated, one house burnt down, washing machines exploding.
4.  Pesticide in drinking water
    Cause:- A mains break occured whilst a pest exterminator was mixing water with a pesticide in his truck (this is probably one of the most common occurences).

In Australia there are thousands of mains breaks per year, how many cross connections are there? No body really knows, so how serious is the problem?

Who is responsible, as we have already mentioned water utilities are with drawing from being regulatory authorities and are purely opting for containment policies. The Plumbing Industry is moving toward de-regulation and self-certification. What about "duty of care" and to what degree is practiced?

When someone does die not if or become serious ill, who is responsible, who is to blame? The Plumber, the property owner, the Water utility or indeed is it a health issue.