[bbqjoe]

This is not so much a food issue as it is a health issue, but it does apply to cooking etc.

This is something that most people wouldn't think about.
In commercial applications it is health code, in some communities it is addressed by building codes.
But either way it is still very easy to contaminate your home or even your communities water supply.
The eaisest way to to do this is by "Cross connection." And I am willing to bet 100% of us are all guilty at one time or another of setting up the potential for it.

Cross connection is when used water is permitted a route to sanitary water.

The simplest and most common method is your garden hose.

Imagine this scenario: You fill up the kids wading pool.
The kids all play in it. The neighbors kids join in. Even the family dog plays with the kids in pool. We now have a nice "Bacteria soup, sitting at optimum temperatures for rapid growth. The garden hose is left dangling over the side into the pool.

Any number of things can now happen, and probably won't, but the possibility is there.

Your foot valve (one way valve) on your well gives up, or maybe the local fire dept. opens a hydrant close by for some reason. Either way a drop in water pressure occurs and creates a vaccumm.
The water in your wading pool is sucked backwards into your home plumbing system, and maybe down into your well.

Or what if you had a garden hose sprayer with fertilizer or insecticides hooked up when the incident occurred.
This is really only one example, and I'm sure there are many more, such as a sink sprayer left in dirty dish water.

The best protection against this is a simple backflow preventer that is attached to your outdoor hose bibs. (Available at your local hardware for about 5 bucks.) These are required at all food handling facilities.

Do you have them at your home?
Do you think you need them?
Will you be getting any soon?