The plumbing systems in homes and office buildings – including your Chicago home – all have two major divisions. One part of the plumbing brings fresh water from the water company into your home before distributing the water, via a network of pipes, to the plumbing fixtures and appliances in the house.
The second part of the plumbing removes dirty water coming from your plumbing fixtures and appliances. This wastewater is collected by the different drains inside the home and transported out of the house into the main sewer line, which then moves the water into the city sewer lines in the street.
When your home’s plumbing is operating as it should, the contents of these two sections of the plumbing system never meet, notes KRS Tidewater Management. If the potable water inside your freshwater pipes ever meets with the grey water or sewage inside the drainage system, your home’s water supply will be seriously contaminated.
This problem usually happens when there is backflow in your plumbing system. Backflow occurs when the water in the plumbing flows in the reverse direction due to severe and unusual variations in pressure within the system. What causes backflow, and how should you handle this plumbing emergency?
What causes backflow?
Two kinds of backflow can happen in your home – backpressure backflow and back siphonage backflow – and each has a different cause.
Back pressure backflow: This happens when the pressure in the downstream sector (drainage system) becomes greater than the pressure in the upstream region (potable water system) of the plumbing, causing the contents of your drainpipes to flow in the reverse direction and back into the freshwater pipes.
These sudden and intense changes in pressure are due to pumps, boilers, line flushing, leaks in the freshwater pipes and firefighting activities.
Back Siphonage Backflow: This is caused by a vacuum or partial vacuum in the public water system or your home’s potable water supply system. The effect of having a vacuum in your potable water supply line is similar to what happens when you drink water through a straw.
Back Siphonage backflow is also caused by firefighting activities. Other causes of this problem are issues in your water main, repairs and breaks in the city main.
Effects of backflow on your home
- Tainted water supply with risk of serious illness
- Sewage odors inside your home due to sewer gases leaking from the drainage system
- Lethal insecticides in your garden hose leaking into the home’s water supply
- Risk of damage to hot water lines and appliances
- Possibility of sewage backing into the house and damaging your walls and flooring
How to detect and prevent backflow emergencies in your Chicago home
Backflow testing is the only reliable way to determine if your home has a backflow problem. Backflow testing is required if your home has an irrigation system or well. If you just bought the house or your plumbing system is old, backflow testing is something you should consider.
It is also a good idea to check your plumbing system for backflow if you do not have a backflow preventer installed. To do this test, you need to have a certified Chicago plumber. A plumber who understands the peculiar plumbing challenges of Chicago homes is best for this job.
If your plumbing is determined to have backflow issues, the best way to solve the problem is to install a backflow prevention valve. The best kinds of backflow prevention devices are automatic ones. Manually-operated backflow prevention systems are not recommended.
Types of automatic backflow prevention devices
Air gaps
Air gaps involve creating a physical space between your home’s potable and non-potable water system. The device operates on simple principles, yet it is highly effective in preventing backflow. You can use air gaps to prevent backflow, whether it is caused by back siphonage or back pressure.
Atmospheric Vacuum Breaker Assembly
This device operates via an inlet valve. When water flows through the pipes, the air inlet valve is closed. However, if the water stops flowing, the valve opens to let air into the system and neutralize pressure imbalances, thereby stopping backflow. This device is best for backflow caused by back siphonage.
Pressure Vacuum Breaker Assembly
This backflow preventer contains an air inlet valve, check valve and shut offs. The check valve is open when water is flowing through the pipes but closes as soon as it stops flowing. The inlet valve is then opened to allow air into the pipes. This system prevents back siphonage.
Double Check Valve Assembly (DCVA)
These devices contain two spring-loaded check valves with shutoff valves and test cocks. The check valve closes when there is a threat of backflow. But if the first check valve fails, the second check valve serves as a backup. This kind of backflow preventer works for both back siphonage and back pressure.
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