Potential Water Contamination due to Backflow

Backflow is the unwanted flow of sewage and contaminated water into the distribution pipes of the potable water supply. Especially in places where portable water systems are connected to a source of potential contamination, polluted water from irrigation systems, industrial discharge, pools, sewage, and plumbing devices can enter the main supply line. Backflow can contaminate entire water supply lines, leading to serious health repercussions in anyone using the contaminated water for bathing, cooking, and drinking. Backflow happens due to inadequate cross-contamination safeguards, such as backflow preventer valves, To claim damages and compensation for the contaminated water refer to the Camp Lejeune Justice Act, this act will give valuable information.

There are two types of backflow:

  • Back Siphonage: Back Siphonage is a reversal of normal flow in a system caused by a negative pressure, which leads to a vacuum. High demand on water supply by emergency Preventer, a break in the water main or a pump failure, can lead to back siphonage.
  • Back Pressure: Backpressure occurs when the pressure downstream becomes more than system pressure, leading to a reversal in the flow of water. Due to back pressure, contaminated water is pushed into the potable water supply.

In the events of a backflow, here are the possible contaminants which can enter the water supply line:


Pesticides, such as insecticides, herbicides, and fungicides, can enter the water stream due to a cross-connection with an irrigation system. Pesticide contamination can lead to nausea, abdominal pain, gastrointestinal problems, headaches, and muscle pain. Even if you have a sprinkler system at home, a faulty backflow preventer valve can lead to leakage of contaminated water into the supply you use for your home. A low pressure in the main city water line leads to back-siphonage of harmful pesticides through sprinkler heads and the irrigation piping system into your drinking water.

Some people also recycle their home’s gray-water (from laundry or shower) to irrigate shrubs or garden beds. However, a backflow can cause this contaminated water to flow back into the main line.


Sewage water contains harmful pathogens that are detrimental for your health. The presence of pathogens, such as virus, bacteria, and parasites, can lead to serious health issues such as cholera, diarrhea, typhoid, hepatitis, gastroenteritis, and worm infections. To prevent sewage water from mixing in with your portable water supply line is to install a backflow device on the sewer line; it allows water from the home to flow to the sewer system but closes when the flow of water is reversed. Even a small leakage or backflow from the sewage lines can render the water unfit for human consumption.


If a fountain or swimming pool is directly connected to the water system for filling, a backflow can release chlorinated water back into the supply line. Chlorine is a disinfectant that is added to public bodies of water to combat bacteria, viruses, and other microorganisms that cause disease and immediate illness. However, Using or drinking chlorinated water leads to difficulty breathing, stomach ache, vomiting, wheezing, coughing, a sore throat, irritation on skin and eyes, and chest tightness.

Stagnant water in firefighting systems

The water used in fire protection systems comes directly from the city main line. However, the stagnant water that fills the pipes of wet fire protection systems is not fit for human consumption. Bacteria thrives in stagnant water, causing the water to become a thick, smelly, black, oily sludge. Additionally, this water may also contain lubricants, chemicals or other pollutants that could cause serious illness. A faulty backflow preventer valve or lack of one can cause this stagnant water to mix in with the treated, “potable” water in the city water supply. This is why law dictates that Fire Backflow Preventer should be annually assessed and maintained to prevent any detrimental effects. A nationally renowned fast food restaurant started complaining about salty water coming out of taps. Upon inspection, it was discovered that the cross-connection with the nearby ship-repair facility had a backflow issue, due to which sea water was mixing in with the portable water supply.


Contracting companies may use potable supply which can cause a pressure drop. Possible backflow can cause harmful chemicals, such as glycol used in the HVAC system, can enter the portable water stream and renders the water unsafe for consumption. To keep the drinking water, backflow preventers should also be installed on the HVAC system lines.

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