Some Cross-Connections Present with Very Interesting Visual Clues



Speaker:                                 Paula M. Tanner, REHS, MPH

Epidemiologist, Jack in the Box



Short Abstract:

The contamination or pollution of potable water does not necessarily manifest itself by the subliminal presence of various chemicals and microorganisms in the water. There is vast documentation of a variety of cross-connections that have presented by serious visual presentations including explosions and fires to the humorous presence of wine and beer or the perplexing observation of backward-running meters.

This article will catalogue the various types of visual clues and evaluate those cross-connections in terms of illnesses and injuries, consequences, and corrective actions.

Long Abstract:

Potable water can become contaminated or polluted by a variety of chemicals, microorganisms, liquids, and gasses. The cross-connections are often identified because of illnesses, injuries, inspection audits and the like.

Visual clues may be a proactive approach to preventing some cross-connections, or even an investigative tool in a debriefing after a cross-connection event. Approximately 80 cross-connections were identified from an extensive data base that had clear visual clues.

Each type of visual clue was catalogued and ranked, and each type of visual clue was evaluated in terms of illnesses/injuries and deaths, consequences, and remedial steps.

Some cross-connection events were humorous in that beer or wine spewed forth from the kitchen sink faucet. In another, the water turned blue from a hydrofluorisilicic acid overfeed at a water treatment plant. And in another category type, a facility complained of an extremely high water bill that investigation determined to be from a cross-connection.

Learning Objectives:


  1. An understanding of the definition of a cross-connection.
  2. Understand the difference between a polluting event and a contaminating event.
  3. Learn how visual clues can be used as an important proactive approach in preventing/limiting cross-connections as well as a valuable tool in determining a cause of a specific cross-connection.