How can contaminated water return to your water system?

Two phenomena can cause backflow: back pressure and siphonage. Siphonage is the most common phenomenon you may encounter. It occurs when there is high water consumption upstream, that is, elsewhere in your water network or in the city's water system¹ . For example, a water main break or the use of a fire hydrant in your neighborhood.

Here is a quick scenario that could happen in a backyard near you:

A person is washing the car in the driveway. Then, this person activates a high-pressure cleaner. This type of application requires a considerable amount of water. Meanwhile, the children are swimming in the pool. A garden hose is soaking in the pool because you wanted to fill it earlier in the day. Since there is a high demand for water in the water system, a siphonage is created in the network. As a result, the garden hose dipped in the pool draws chlorinated and contaminated water from the pool into your drinking water system. As a result, the water flowing from your kitchen tap is now contaminated. Your family is the first victim in this situation. But do not panic!

Here are some recommendations and suggestions.

What can be done to avoid such an incident?

Several best practices can help you reduce the risks:

Avoid soaking garden hoses, whether in a pool, a watering can, or a soap dish,
Reduce your water consumption for a short time by extending it over a longer period,
Turn off your garden hose and empty it after each use.

Various protective measures are available to prevent water contamination in the event of such an incident:

Equip your outdoor water outlets with an atmospheric vacuum breaker (AVB / CSA B64.1.1)² with an antifreeze connection. This will enable you to keep it in good working order throughout the winter.
Equip your garden hose with a spray gun. It's not ideal, but it's much better than having a hose alone.
Equip your hose with a roller so you can put it away after each use, making sure to empty it. Continuous pressure for more than 12 hours² could damage your C-VA and render it ineffective.

It would be a shame to miss your family vacation because of such a trivial activity. So remember to make these modifications to your outdoor installations to protect yourself and your children.

Hot summer leads to high water consumption

How can contaminated water return to your water system?

What can be done to avoid such an incident?

References:

Articles you may also like