A backflow prevention device is the unsung hero of any safe, reliable plumbing system. While backflow prevention devices come made for a variety of pluming situations, apartments and homes with portable water and septic systems rely on them more to prevent costly damage from waste water reversal. It is important to get yearly backflow testing to make sure that any backflow device is working properly.
What is backflow?
Backflow is the unwanted reversal of waste water from the sewer or septic system into the drinkable water supply source. While many city blocks have backflow devices built into the main lines, many homes, especially those that rely on well water or have septic systems require the home-owner to be responsible and have it installed.
A plumbing system without backflow devices can often be detected when a drain bubbles as liquid is removed. These bubbles are air moving out of the pipe as it is replaced by water. If a backflow prevention device was installed, that air would simply slip out a vent and the water would drain unobstructed by the positive pressure.
The reason why backflow happens
What the backflow prevention device does is maintain neutral pressure in the pipes. If sewer gas was starting to expand in a septic system or drinkable water washing down the drain created positive pressure, in both instances the backflow device will kick on. If no backflow device was present, in the first case the sewer gas would force solid, liquid, and gas up through drains and possible even contaminate the clean water supply. In the second case the excess pressure could reverse sewage through drains or even crack the septic tank causing a sewage spill into the water table, permanently damaging water quality.
A backflow device is a one-way or two-way pressure release valve rated to handle a threshold of pressure. While a backflow for a home can be a small vent, backflow devices for city lines can discharge huge volumes of sewer gas or pressure from concrete heat buildup instantly. It does this by releasing positive pressure, and once the internal pressure is neutralized, it seals shut: much like the valves inside a person’s circulatory system.
Less dangerous— except to septic systems, negative pressure can lead to some annoying plumbing issues such as slow draining. More expensive backflow prevention devices exist that can also neutralize negative pressure and are often utilized in apartment buildings and dormitories where the combined effects of negative pressure in an intricate plumbing system can be more noticed by tenants.
For individuals living in the country, a two-way pressure release device that is up to date on with backflow testing is the most valuable long term investment for the longevity of a septic system and the health of the water table.
The importance of backflow testing
This can be extremely dangerous especially for a well water and septic tank system as it can reverse sewage from the septic line and contaminate the well. The reason why backflow testing becomes so important is that sometimes either the backflow device, or the line to it can get obstructed.
During backflow testing, a professional can not only determine if the line is clogged, but can also remove serious debris. Sometimes the physical venting system or another part of the device can become outdated, rust shut, or can malfunction for any other reason.
The ultimate sign that a home or building’s backflow device is malfunctioning is the characteristic bubbling in the sink drain. If such symptoms are noticed, the most responsible course of action is to conduct backflow testing immediately.