A high pressure washer utilizing soaps or cleaners connected to a hose bib or other sources of water without a backflow preventer.A chemical sprayer attached to a hose without a backflow preventer.A water softener drain or other type of water conditioning equipment directly connected to a sanitary sewer.Other common cross-connections found in plumbing and water systems include: The water in these systems can be rusty and oily and could pose a health threat if consumed. Another example would be the makeup water for a hot water heating boiler. What does a typical cross connection look like?Ī common example is a garden hose connected to a hose bibb at one end and the other end of the hose lying in a pool, puddle or any other source of non-potable water. The degree of hazard to health will be dependent on the type and amount of contaminant, the amount of time the situation goes unnoticed and whether or not a protective device is in place. Any contaminants that had a chance to enter the water supply will start to flow towards any point of use (plumbing fixtures) in homes or businesses. When the repair is completed and the regular pressure is restored everything starts to flow in the proper direction. This is back siphonage and if there are cross connections, contaminants can be drawn into the water system. When the valves around the repair site are closed, the flow of water is stopped to all points of use such as homes and businesses and begins to flow backwards towards the repair. Increases in pressure can be created by booster pumps, temperature increases in boilers, interconnections with systems operating at higher pressures, and elevated piping (e.g., 30 feet above finished grade).Īn example is when there is a water main break and the area must be isolated and repaired. It can happen when there is a connection to a non-potable supply operating at a higher pressure than the water distribution system. Back siphonage can occur when there is a stoppage of water supply due to nearby firefighting, a break in a water main, high velocities in pipe lines, line repair or break that is lower than a service point, lowered main pressure due to high water withdrawal rate such as firefighting or water main flushing or reduced supply pressure on the suction side of the booster pump.īack pressure is pressure that is greater than the municipal water system supply pressure. The effect is similar to drinking water through a straw. Some types of backflow preventers require testing to ensure that they will work as intended and there are some that do not require testing.īack siphonage is backflow caused by a negative pressure (i.e., a vacuum or partial vacuum) in a public water system. Simply put, a backflow preventer is a device or assembly that prevents backflow. Backflow may occur due to either back siphonage or back pressure. Please check with the respective municipality or supplier of water for program information.īelow is a list of Municipalities in Ontario who currently have Cross Connection Control By-Laws or Programs:Ī cross-connection is any actual or potential connection between a potable (drinking) water system and any source of pollution or contamination.īackflow is a flowing back of water or reversal of the normal direction of flow. Therefore, there may be differences between the types of cross connection programs that different authorities may have implemented. The responsibility for establishing and administering a cross-connection control program is with the individual municipality or water purveyor (authorities). Many people are unaware that backflow conditions can jeopardize system water quality, posing a health risk to consumers drinking water from the system. Dennis O’Connor states that “as part of their comprehensive distribution system program, water providers should have active programs, working together with building inspectors and public health agencies, to detect and deter cross-contamination”. In Chapter 7 of the Report of the Walkerton Inquiry, A Strategy for Safe Drinking Water, the Hon. Importance of Backflow Prevention in Ontario
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