According to the Canadian Standards Association, a cross connection is defined as any actual or potential connection between a potable water system and any source of pollution or contamination. Cross connections are present in every water system; depending on the size of the system, hundreds or thousands of potential cross connections can exist.
Installing back flow preventing devices is critical. Many people can be subject to contamination without realizing the problem. Once installed, back flow prevention devices must be tested annually by a licensed cross connection control specialist.