What is backflow?
Cross connection is defined as a physical connection between drinkable water and a liquid or gas that could make the water unsafe to drink. Wherever there is a cross connection, there is a potential threat to public health from the liquid or gas contaminants.
Backflow is defined as water flowing opposite to its intended direction, either from a loss of pressure in the supply lines or an increase in pressure on the customer’s side. In either of these situations, if any affected customer’s pipes include a cross connection, contaminants could be drawn through the cross connection into that customer’s pipes; and, if the backflow continues, perhaps even into the water mains.
In 1974, the Safe Drinking Water Act (SDWA) came into existence. Backflow preventers have been used to stop contamination during a drop of pressure and allowing back-siphonage into the main water lines. Backflow devices use valves to keep the water flowing in one direction.
In Texas, the Texas Commission on Environmental Quality (TCEQ) is charged with making sure local water providers stay compliant with the SDWA.
Backflow incedents do occur.
- In 2016, a backflow incedent in Corpus Christi made international news. Hydrochloric acid and other chemicals were released into the water supply due to a faulty backflow preventer at an asphalt plant. This led to a no-use notice. Most of us a familiar with a boil notice, but in this case, not only would boiling the water not suffice, but you could also not even take a shower with it because of the chemicals present.
- In 2015, also in Corpus Christi, a faulty backflow preventer on an irrigation system led to a backflow incident involving E-coli entering the city water supply.
- More Case Studies of Backflow Incedents
