AQWEST customers obtain their high quality drinking water via an underground network of pipes. Water flows under pressure from treatment plants to properties throughout the city. In unusual circumstances, two events may occur simultaneously to cause a threat to the quality of your drinking water. These events are called cross-connection and backflow.

What is cross-connection?

A temporary or permanent connection between your drinking water supply and any other system containing fluid other than drinking water is called a cross-connection. One example of a cross-connection is an automatic weed-killing product attached to the garden reticulation system. Another example is the common practice of using a running hose to clear a blocked drain or sewer.

What is backflow?

Certain conditions, such as a burst pipe or use of a fire hydrant in the street, may cause the pressure to drop to a level which causes the water flow to go in reverse. This is known as backflow. There are two types of backflow: backpressure and backsiphonage. Backpressure can be caused by a pump being inadvertently connected to the water supply. Backsiphonage may result from a burst main or when fire fighters access water from a hydrant, reducing pressure suddenly and causing water to flow the other way.

Cross-connection and backflow can cause a health threat During a backflow situation there is a threat that poisons can enter the water supply because of a cross connection (eg. chemicals, pesticide, bacteria, industrial waste). Poison can flow into your drinking water, or even into the city water supply. Contamination of drinking water can cause illness or, in extreme circumstances, death.

Backflow can be prevented

AQWEST is committed to supplying high quality water to its customers at all times. Protecting the system against backflow is a high priority. Domestic, commercial and industrial customers need to be aware of their responsibilities to prevent backflow. Properly designed and installed plumbing systems will ensure protection. You can improve protection by installing and maintaining backflow prevention devices.

Four basic ways to prevent backflow

The following tips will help protect the quality of your drinking water.

• Ask AQWEST or a qualified plumber for advice.
• Use a licensed plumber to do all plumbing work.
• Ensure cross-connection situations such as reticulation systems are protected with a backflow prevention device.
• Never immerse hoses in containers that are being filled and never use running hoses to clear blocked drains.