Backflow is water going in the direction it’s not supposed to be running to. It can cause a lot of problems, particularly if it happens in your house.
It can cause water contamination and damage, leading to health risks and costly house repairs.
Just imagine wastewater from the sewerage going back up to your Australian home. It’s not a pleasant thought, is it?
There are two types of backflow – siphonage and backpressure.
Siphonage backflow or back-siphonage happens when the water pressure in the water pipes drops, leading to negative pressure or a vacuum.
It can prevent water from reaching your faucet or where it should be. A broken water main line may cause this and even firefights when firefighters tap into the main water line.
Meanwhile, backpressure happens when there’s too much pressure in the water line or downstream versus the pressure from the supply line.
It means that water is getting pushed back into the water supply. One of the most typical causes is the thermal expansion of water caused by boilers and water heaters.
And those are just the common ones cited by plumbing professionals.
How to Prevent Backflow From Happening in Your House
All the while those causes mentioned above are mostly out of your control, there are still ways to prevent backflow from happening in your home. Some of those steps you can take are the following:
1. Placing Air Gaps
One of the simplest methods to prevent backflow is to let the best plumber Sydney has available install an air gap between your water lines, especially ones that connect to drains.
For example, in a sink, there’s always a water faucet and a drain. The gap between the sink and the drain (and the sink’s flood level) is called an air gap.
By the way, the flood level is the highest point the water can reach in a sink if you flood or fill it.
The way air gaps work is that they prevent backflow pressure from siphoning unwanted water.
In the sink example, the air gap will prevent the faucet from siphoning the water in the sink because of the negative pressure. Instead of siphoning sink water, the faucet will siphon air.
Of course, this doesn’t only work or is applicable in sinks. Usually, some gray water drainages have air gaps in them.
Those air gaps also prevent sewage backing up from reaching areas like sinks. And if you’re recycling water, you need to have air gaps in mind when setting up your system.
2. Installing an Atmospheric Vacuum Breaker (AVB)
An atmospheric vacuum breaker is a simple device that acts like an air gap between pipes.
It’s usually made of brass, and it’s shaped like a regular 90-degree pipe elbow. A hood on an AVB’s top allows air to seep inside it.
If there’s negative pressure or backflow, it’ll pull air from outside through the hood.
A poppet valve is in place to prevent water from escaping the AVB through the hood.
When there’s no negative pressure, this poppet will be shut off, preventing any liquid from escaping. AVBs are usually installed six inches above the ground or higher.
Typically, AVBs are installed in flush valves, toilets, and faucet valves. Of course, there are situations wherein they’re not the best choice in preventing backflow.
For one, if the pressure is constantly isn’t high enough for the poppet to close, the AVB may introduce a lot of unnecessary air in the pipe.
Also, if the air around the AVB is constantly contaminated, it’s best not to use it on a pipe with potable water, especially if you’re using a water softener in your residence.
Installing a Double Check Valve (DCV)
It’s rare for residential homes to install a double check valve to prevent backflow.
It works because DCVs have a gate or ball valve that prevents water from flowing in the opposite direction where they’re supposed to flow.
They have test cocks and shut-off valves to allow testing and disabling the connection as well.
DCVs are usually installed in water service lines and public sewer connections as it’s expensive and too intricate for residential use.
However, it’s highly reliable when maintaining the water flow in one direction.
For a more residential-friendly DCV, you can settle for a dual check valve. Unlike the double check valve, a dual check valve doesn’t have shut-off valves and test cocks.
They’re also much cheaper. Nonetheless, a few experts aren’t confident about the effectiveness of dual check valves.
Those are the ways and devices you can use to prevent water backflow in your home.
If you’re not confident enough to do or install them by yourself, don’t hesitate to get help from plumbing professionals.