The term “back flow’ describes the movement of water from its destination (i.e. a sink or toilet) back towards its source in the water line. There are a number of measures and mechanisms in place which act to prevent back flow, however poor repairs and installations, and normal wear and tear can prevent such mechanisms from working properly, leaving a homeowner with a potential contamination problem.
There are two types of back flow: back siphonage and back pressure. Think of back siphonage as using the same mechanism as a drinking straw. When negative pressure forms from a reduction in pressure in the water supply, a vacuum is formed “sucking” water from the system back into the supply line. Back pressure occurs in opposite to siphonage, so think of blowing air through a straw into your beverage until it erupts with bubbles. In other words, when the pressure of the system is greater than that of its supply line. This is most likely to occur from improper installation of devices such as water heaters, which may demand a higher pressure than the level of pressure in the water main. Both forms of Back flow can range from minor to severe levels of contamination of the potable water supply.
Given the source of the contamination and the seriousness of the problem, backflow is categorized in severity from levels 1-5, with 1 being no risk and 5 being representing a serious risk to human health, representing a contamination by human waste.
Luckily, there are more than a few measures in use to prevent backflow, however it is important that they are installed and maintained properly over time. Executive Plumbing & Drain can meet all your backflow needs to keep your family and community safe from the risks of contamination.
Check valves are one such measure in place to prevent the contamination of the potable water supply by back flow. Depending on the risk category of the installation, there are numerous check valves in use to meet the demands of the system ranging from the mechanical simplicity a ball check valve, which essentially works like a Chinese finger trap, plugging the line when backwards force is applied to it, to the behemoth reduced pressure zone backflow preventers often seen on municipal grounds. Even the flap disc in a standard toilet flusher system is a type of check valve.
Another very common form of backflow prevention is called an air gap. Some air gaps simply refer to the space between a faucet and sink basin, with the faucet being high enough above the basin that were overflow of the basin to occur, the contaminated water could not physically reach the faucet and be siphoned back into the supply line. Even if the term sounds unfamiliar, if you have lived in a domicile with a dishwasher, then chances are you have seen one of these in action. The small nob usually in place next to the kitchen sink faucet is an air gap which prevents the flow of contaminated sink water back into the dishwasher through the washer’s drain pipe, since it is usually connected to the same drain system as the sink. Finally, the cold water cistern, the back of a toilet, is another type of air gap for prevention of back flow in the case of a toilet back up.
It is of utmost importance to public health that back flow is prevented and that such preventative measures are installed and maintained properly to keep you and your loved ones safe. If you suspect you may have a problem with backflow in your home, do not hesitate to call Executive Plumbing & Drain!