Backflow - A & L Plumbing and Piping

A and L Plumbing & Piping
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What is a Backflow?
Definition:   Backflow is the undesirable reversal of the flow of water from its intended direction in any pipeline or plumbing system. Backflow is dangerous because it can allow drinking water in plumbing systems to become contaminated and unusable.
    Backflow can occur in a number of ways including (but not limited to) the public water system losing pressure, back pressure (your water pressure exceeds the pressure of the distributor) or back siphonage (when the distributor water pressure falls below yours due to a water main break, cleaning of fire hydrant line and etc.)
The loss of pressure is not the biggest problem with a back flow problem, but the possible introduction of harmful chemicals that can come from a cross-connection (a connection of a potable water system to a non-potable system or a system of questionable water quality) If a cross connection occurs when a backflow problem occurs you can get some harmful chemicals in your water supply.

A few harmful chemicals are
  • Untreated river, sea or lake water,
  • pesticides
  • herbicides
  • fungicides
  • propane gas
  • boiler water with chemicals
  • anti-freeze
  • chemicals
  • water from car wash establishments
  • dyes
  • sewage
  • worms
  • heavy metals such as arsenic
  • petrochemicals
  • water from flush toilets
  • bacteria cultures from laboratories
Modern technology has provided us with new tools to prevent backflow from nonpotable sources into our public water systems. They are called backflow prevention assemblies; reduced pressure (RP) or double check valve (DC) types

Backflow prevention assemblies have internal springs and seals, and moving parts that wear out over time. Regular testing is required to ensure backflow prevention assemblies are functioning properly and have not been bypassed. A visual check of air gap assemblies is sufficient, while mechanical assemblies must be tested with special equipment.

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