Cross-Connections
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Cross-Connections

Do you have any?

We all need to do our part to help protect our water supply.  Do you know what a cross-connection is?  This article is intended to help educate customers of potential hazzards associated with cross-connections.

WHAT IS A CROSS-CONNECTION?

A cross-connection is an unprotected actual connection or a potential connection between a potable water system used to supply water for drinking purposes and any source or system containing unapproved water or a substance that is not or cannot be approved as safe, wholesome and potable. By-pass arrangements, jumper connections, removable sections, swivel or changeover devices or other devices through which backflow could occur shall be considered to be a cross connection.

THERE ARE TWO TYPES OF BACKFLOW

1. Backsiphonage. A negative pressure that can be caused by water main breaks, fire hydrant flushing or firefighting. Backsiphonage can draw all the water from a private water system. If this water is used for boiler's, sprinkler systems etc. it could contain contaminated water.

2. Backpressure. This is caused by the pressure in the private water system exceeding the district's water system usually caused by a privately owned pump used to increase pressure inside a single structure. This causes water to be forced back into the public system.

THERE ARE FIVE TYPES OF BACKFLOW DEVICES

1. Air Gap -Used mainly on tanks and faucets, it is a gap between the pipe and the container. Requirements: The gap needs to be a minimum 2 times the supply pipe diameter.

2. Atmospheric Vacuum Breaker - Used mainly on lawn irrigation systems. It has an air inlet valve that will drop to draw in air thus preventing sprinkler system water from entering the District's water mains.

Requirements:

  • Not under continuous pressure for more than 12 hours
  • No downstream valves
  • No backpressure
  • 6" above high point of use

3. Pressure Vacuum Breaker - Used mainly on lawn irrigation systems. It has a one way check and a spring loaded air inlet valve that closes when Public water main pressure drops.

Requirements:

  • No backpressure
  • 12" above high point of use
  •  Protect from freezing

4. Double Check Assembly - Operates similar to a Pressure Vacuum Breaker. Used on low hazard applications and on fire lines.

5. Reduced Pressure Principle Assembly - Used on high hazard applications and is a combination of check valves and an air inlet allowing water from the private system to vent when the district's pressure drops.

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