Many people don't know how easy it is to potentially contaminate their own private water well. The problem can occur when a person is using an outside water hose with a chemical dispensing sprayer or washer attached. What can happen is when the water supply to the hose is shut off, the negative pressure within the well casing created by gravity drawing water back down, creates a siphon action which draws water backwards through the hose and piping.
Imagine that you are watering your lawn with a hose end sprayer and you're applying weed killer onto those pesky dandelions. Then your cell phone rings and you lay down the sprayer to take the call. Suddenly, you realize that it's lunch time so you go turn off the faucet and go inside for a bologna sandwich. The resulting negative pressure could then draw water back through the hose by siphon action. That water could quite possibly be contaminated with the chemical weed spray you've been using.
There's an incredibly simple solution to this potential disaster and it won't cost you an arm and a leg. A device called a back-flow preventer or diverter can (and should be) installed on every outside faucet of your house. The back-flow diverter is a heavy duty diaphragm valve which allows water to flow freely out of your faucet but prevents water from being drawn back into the system. With a trip to your local hardware store and a few simple twists of your wrist, the contamination of your private water supply
be one less thing to worry about.