Your home’s plumbing is built around one simple principle: water flows in one direction. Fresh water comes in, wastewater goes out. It’s a system most of us never think twice about—until something goes wrong.
Backflow is one of those plumbing problems that doesn’t get talked about as much as clogged drains or leaky pipes, but it can be one of the most serious issues a homeowner or business owner faces. When backflow occurs, contaminated water reverses course and flows back into your clean water supply. That’s not just a plumbing problem—it’s a health hazard.
Here’s everything you need to know about what causes backflow, how to spot the warning signs, and most importantly, how to prevent it.
What Is Backflow?
Backflow happens when water moves in the opposite direction of its intended flow through your plumbing system. Your pipes are designed to keep fresh water and wastewater completely separate, but certain conditions can cause that separation to break down.
When backflow occurs, dirty water—water that may contain bacteria, chemicals, sewage, or other contaminants—can flow backward into the pipes that supply your drinking water, your shower, or your kitchen sink. In a residential setting, this is a serious sanitation concern. In a commercial setting, it can also mean major code violations and potential liability.
In Louisiana, backflow is a particularly relevant issue. The high water table, frequent heavy rain, and flooding throughout the New Orleans area and the Northshore all create conditions where backflow risks are higher than in many other parts of the country. That’s also why businesses have a mandatory backflow testing that is required by law.
What Causes Backflow?
There are two main types of backflow, each with a different cause.
Back-Pressure Backflow
This happens when the pressure in your plumbing system is exceeded by pressure from a connected source. In other words, something downstream is pushing harder than the water coming in. This is common in commercial settings where boilers, pumps, or other pressurized equipment is connected to the water supply. It can also happen in irrigation systems when a pump creates more pressure than the municipal supply line.
Back-Siphonage Backflow
This type occurs when there’s a sudden drop in water pressure in the supply line. Think of it like a vacuum effect—when pressure drops, water gets pulled backward. This can happen when:
- A water main bursts somewhere in your area
- A fire hydrant is opened nearby, drawing a large volume of water quickly
- There’s a major break or repair happening at the municipal water facility
- Your home experiences a significant pressure drop from a plumbing failure
In either case, the result is the same: water that should be flowing away from your home reverses direction and contaminates your fresh water supply.
Common Causes of Backflow at Home
While the mechanics behind backflow involve pressure, the real-world triggers are often things homeowners deal with regularly:
Flooding. When the ground around your home becomes saturated, the pressure on your underground pipes increases. This is especially relevant for New Orleans area homeowners, where flooding can be a fact of life during storm season.
Severe clogs. A major blockage deep in your sewer line can create enough back pressure to force water in the wrong direction. If multiple drains in your home are slow or backing up at the same time, this is a warning sign worth taking seriously.
Burst water mains. When a main water line breaks in your area, pressure drops across the whole system. This is one of the more common causes of back-siphonage.
Irrigation systems. Garden hoses and irrigation systems submerged in water—like a hose left in a pool or a sprinkler head sitting in a puddle—can act as a direct pathway for contaminated water to be pulled back into your supply line.
Cross-connections. A cross-connection is any physical link between your clean water supply and a potential source of contamination. These can exist in older homes where plumbing wasn’t installed with modern backflow prevention standards in mind.
How Do You Know If Backflow Has Occurred?
Backflow isn’t always obvious, but there are signs to watch for:
- Discolored water coming from your taps—yellow, brown, or murky water is a red flag
- Unpleasant odors from your faucets or drains that smell like sewage or chemicals
- Unusual taste in your tap water
- Sediment or debris coming out of your faucets
If you notice any of these signs, stop using your tap water immediately and give us a buzz. Backflow contamination is not something to wait on.
How to Prevent Backflow
The good news is that backflow is very preventable with the right equipment and regular maintenance.
Install a Backflow Prevention Device
A backflow preventer is a device installed directly on your main water line that acts as a one-way gate. When water is flowing normally, the device stays open. If pressure drops or reverses, the device closes automatically, stopping contaminated water from entering your clean supply.
There are several types of backflow preventers, and the right one depends on your property and your plumbing setup:
- Pressure Vacuum Breaker (PVB): The most common and affordable option. Easy to install and maintain, though not recommended for indoor use since they can release water when activated.
- Double Check Valve (DCV): Works both indoors and outdoors and can be installed vertically or horizontally. A step up in both protection and cost from a PVB.
- Reduced Pressure Zone Assembly (RPZ): The most reliable option available, and ideal for properties with irrigation systems or where higher levels of contamination risk exist. These are the most expensive but offer the strongest protection.
If your home was built before modern plumbing codes were in place, there’s a chance you don’t have a backflow preventer installed at all. If you’re not sure, that’s worth a phone call to find out.
Schedule Regular Backflow Testing and Inspections
Even if you have a backflow prevention device, it needs to be inspected and tested regularly to make sure it’s working properly. A device that has worn out or failed offers no protection. In fact, for commercial properties, regular inspections and certifications are required by law.
At Goodbee Plumbing, our master plumber Scott Harrison holds a backflow certification. We can inspect your existing device, let you know if it needs repair or replacement, and make sure you’re fully up to code.
Be Mindful of Cross-Connections
Take a walk around your property and pay attention to how hoses and irrigation equipment are set up. Never leave a garden hose submerged in a bucket, pool, or puddle. Make sure sprinkler heads are positioned above the ground rather than sitting in standing water. These small steps can go a long way in reducing cross-connection risks.
Backflow Prevention for Commercial Properties
If you own or manage a commercial property, backflow prevention isn’t optional—it’s required. Every business must have a certified backflow prevention device in place to protect the local water supply. Failure to maintain and certify your device can result in fines or loss of water service.
Goodbee Plumbing has been serving commercial clients across Covington, Metairie, New Orleans, Jefferson Parish, and throughout St. Tammany Parish for over 25 years. We understand local commercial plumbing codes and can help make sure your property stays compliant.
Give Us a Buzz
Backflow might not be the most glamorous plumbing topic, but it’s one of the most important. Whether you need a backflow preventer installed, your existing device tested and certified, or you’ve noticed signs that something may already be wrong, Goodbee Plumbing is here to help.
Same-day service is available for most jobs, and we’re always happy to provide a phone estimate before we get started. Call us at 985-893-1883 or schedule your service online today.