Cross Connection

Cross Connection Control Program

What is Cross Connection Control Program?

Under the requirements of the Safe Drinking Water Act, Part 14 and the Administrative Rules is the Cross Connection Rule that public water systems must follow regarding cross connection control.  Under these rules, drinking water providers are required to implement and maintain a Cross Connection Control Program to protect the public drinking water supply from the possibility of contamination or pollution.  As part of these requirements, the City of Lapeer has adopted a Cross Connection Program within Chapter 22 of our City Ordinance.  Our program outlines requirements needed to protect our drinking water from a cross connection.

What does a Cross Connection Program include?

A Cross Connection Control Program includes a mixed bag of tools, as follows: the authority to enter a building to inspect for cross connection; backflow device testing requirements; backflow device placement; criteria for determining high hazard vs. low hazard businesses; a time line for inspection depending on the degree of hazard; and letters used to communicate cross connection requirements which include penalties for not complying.  

Through the program cross connections professionals have the authority to enter a building or dwelling to perform inspections on commercial, industrial, and residential properties for connections between the public water supply and a contaminated water source, chemicals and pollutants.  Wherever a connection exists between potable water and non-potable water, a backflow prevention device must be installed at the connection point.  The inspector checks for backflow device placement and the correct use of the device.  There are several types of backflow devices used to prevent contamination of a drinking water supply.  The type of device used depends on the degree of the hazard. 

What is a Cross Connection?

A cross connection is any temporary or permanent connection between a public water system or potable (drinking) water source and a non-potable source that provides a path for pollutants or water of questionable quality to enter the public water supply through a reversal of flow (i.e. backflow) due to backpressure or backsiphonage. 

Back pressure flow is created by a pump or a malfunction in a private water system that causes the pressure within the private system and downstream of the public water supply to become greater than the public water supply.  Due to the pressure, shift contaminants within the private system will be pushed into the public water supply.  Back pressure flow can also take place if the pressure in a public water supply drops due to a main break, fire demand, and/or water main flushing.  This pressure drop in a public system could create a pressure shift in which the private water system pressure is greater than the public water system, again allowing contaminants within the private system to enter the public system.

Backsiphonage is caused by a negative pressure in the public water supply (i.e., a vacuum or partial vacuum).  The effect on flow is similar to sipping water from a straw.  The creation of negative pressure will allow contaminants to be pulled into a potable water supply.

Why do water suppliers need to control cross connections?

Since the adoption of the Cross Connection Rule much effort has been spent by Michigan water providers in maintaining effective cross connection programs.  Unfortunately, despite the best efforts of the water providers, there continue to be documented cases in Michigan and throughout the United States where non-potable water or contaminants have entered the potable water system via cross connections.  In Michigan there have been past cases where ammonia refrigerant, propylene glycol, and soap have backflowed into public distributions systems through unprotected cross connections.  Therefore, drinking water providers must continue to use whatever tool are available to them in eliminating and preventing cross connections within the public water supply.

Where can I find cross connections?

Common residential cross connections:

  • In filling a pool, a landscape water feature, or a yard chemical tank with a garden hose, if the garden hose is fully submerged and a main break occurs that created a backsiphonage, non-drinking water or chemicals could then be sucked into the public water system.
  • While applying fertilizer with the use of an applicator that connects directly to your garden hose, if a main break occurs or a large demand of water is needed for a fire, backsiphonage could be created resulting in fertilizer being pulled into the drinking water system.

  • Garden hoses are an easy way to fill all kinds of things, but in many cases in using a garden hose the air gap ( a type of back flow preventer) is removed which allows for the possibility of a backsiphonage occurring.

  • Lawn Sprinklers are another common cross connection.  Sprinkler heads are located in the ground, and at times water puddles around these heads.  If a proper device is not used and a large demand is created on the water system causing a backsiphonage, all kinds of contaminants including fecal matter can be pulled into the drinking water system.

Annual MDEQ Water Supply Cross Connection Reports:

Additonal Information: