You may not think of your garden hose as a dangerous object–but it’s important to know how easily you can contaminate your drinking water when using one. And even worse, you might introduce pollutants into your neighborhood’s water system resulting in widespread illness.
Let me explain how this can happen. As an example, let’s say you want to spray pesticide on your lawn, so you connect a sprayer filled with chemicals to your hose. And while you’re applying these chemicals, a contractor several blocks away breaks a major water line. When the water line breaks, there’s a large drop in water pressure and this creates what is called back siphonage. In other words, instead of the water pushing out, suction occurs and pulls the pesticide right into the water line! Now you and maybe your neighbors have a dangerous situation–contaminated drinking water.
Any connection between drinking water (potable water) and non-potable substances is called a cross-connection. One way to prevent cross connections from your garden hose is to install a hose bib vacuum breaker at the hose connection. They’re inexpensive and easy to find at any hardware or home improvement store. When pressure is lost, the vacuum breaker will prevent contaminants from flowing back into the drinking water.
There are many other scenarios for cross-contamination. Your hose could be lying in a puddle of muddy water. Or a hot tub, or swimming pool.
Short hoses and flexible connectors inside the house can cause problems, too. Never leave a hose lying in a laundry tub if it’s connected to your faucet. And if you have a darkroom or if your child has a chemistry set, you should have a vacuum breaker on the faucet.
It’s best to disconnect your hose completely from the spigot when not in use.