One of the major worries that occupy the minds of many homeowners is some kind of flooding. Outside of coastal or river floodplains, the biggest risk of flooding comes from something in the home not working properly. One of the causes of residential flooding is backflow from the sewage system. Use this guide to understand what backflow is, why it’s a serious problem, who’s at risk of it, and what you can do to prevent it.
What Is Backflow?
Backflow is the phenomenon of water flowing through a pipe in the opposite direction than was intended. In water supply pipes, it means water flowing back from the outlet to the source. In drains or sewage pipes, it results in wastewater flowing back to the drains in the system.
The key to remember with backflow is that it may not always go back to the source. Rather, backflow affects the lowest parts of the plumbing system. This is why you often see residential backflow through floor drains in a basement, in shower and bathtub drains on the floor level, or floor utility drains on the first level.
6 Risks Associated with Backflow
Backflow is a serious problem, whether it’s coming into your home or from your home to the potable water supply. Consider these six significant risks with both supply and waste backflow issues.
1. Household Flooding
For sewage backflow, household flooding is one of the biggest issues on most property owners’ minds. The waste mixture flows back into basements, bathrooms, and utility rooms. Then it flows elsewhere. Beyond the immediate concern of water, floods risk soaking flooring, walls, wood studs, and more. In the short term, this causes swelling and deterioration. In the long term, it can present problems, like mold, if not dealt with quickly and properly mitigated. Some types of mold release mycotoxins which can cause problems ranging from digestive issues to lung and immune system damage. In some cases, exposure can become fatal, especially in vulnerable populations like young children, the elderly, and the immune-compromised.
2. Water Supply Contamination
On the freshwater supply side, backflow can lead to source water contamination. Of primary concern are areas where backflow may naturally occur, such as well pumps and outdoor spigots. Water pressure that drops suddenly can create a vacuum that draws water back into the pipe. In your yard, this can draw in dirt, animal excrement, and chemicals from lawn treatments. If you have a hose in a pool or other source of standing water, it can draw that water back in with whatever contaminants it may now contain. This is part of why you boil water if you’re on a municipal water supply that loses pressure.
3. Sewage Exposure
When you have sewage backflow, you also have to deal with the exposure to whatever is in that sewage. Annoying but generally harmless contaminants include oils, food grease, and hair. However, sewage also contained feces, urine, spoiled food, and more. Cleaning up the backflow exposes you to everything it contains. If you don’t exercise proper precautions, this exposure can cause stomach cramps, diarrhea, vomiting, liver illness, nausea, headaches, loss of appetite, and weakness. Contained in the sewage can be harmful bacteria and parasites like worms and protozoa. If left untreated, exposure to some of these contaminants can cause serious health problems and can potentially be fatal.
4. Pipe Damage
It seems like pipes are meant to have liquid flow through them, so why would it damage pipes if it flows in the wrong direction? Not all pipes are soldered together, but there are pressure fittings in some applications. When the pressure reverses, those fittings don’t work properly, allowing for the fittings to loosen or come apart. Further, backflow can be the catalyst that causes a burst pipe in aging or damaged plumbing. The contaminants in the backflow can also cause the pipes to wear more quickly if they aren’t rated to handle what’s in the backflow.
5. Electrical System Damage
You may not think much about your home’s plumbing and electrical systems interacting, which is true under normal circumstances. However, in the event of any kind of flooding, that water is uncontrolled and may run to where it’ll encounter your home’s electrical system. When this happens, it can short out the system, cause damage to wires and outlets, and ruin some appliances. At the extreme, it can cause a short in the electrical system that can start a fire. On top of dealing with the backflow itself, now you may need to repair some or all of your electrical system.
6. Trouble Selling Your Home
When you own a home, part of what you should frequently consider is what will make selling your home easier or more difficult when you’re ready. If you’ve had backflow issues, your home may have other issues that we’ve discussed above. An inspection will likely uncover these issues and can provide a reason for a buyer to back out of an offer or ask for concessions in the transaction.
How to Prevent Backflow
Backflow is most commonly prevented through a backflow prevention valve. This is a special one-way valve installed on plumbing lines that allows liquid to flow in one direction but not come back. On supply lines, you may install a backflow prevention valve on the supply main that comes into your home. On the sewage line, you typically install this at the lowest point in your waste lines before they leave your home. This is often in a basement. However, it could be installed on the line somewhere outside, on your property. Where you install the valve will determine what kind of backflow valve you’ll need.
Keep in mind that you want the valve accessible so that you can perform annual maintenance. This includes opening the valve cover, removing anything that has gotten caught, and testing it to ensure it still opens and closes properly.
Who’s At Risk of Backflow Incidents?
Any building can be at risk of backflow issues; however, some are at higher risk than others. Homes at the top of a hill or that have hoses permanently running to fixtures are at higher risk of supply line backflow issues.
Homes at the bottom of a hill, in low-lying areas, or in floodplains are at higher risk of sewage backflow. Remember that water flows down and comes out at the lowest point possible because it follows the path of least resistance. Additionally, if you’re on a septic system, you may have a higher risk of sewage backflow when the tank is full, if there’s a clog in the line to the tank, or if the drain field isn’t working properly.
People around Nanaimo turn to Twin Peaks Plumbing, Heating & Gas when they want home services they can trust. Our team provides a wide range of plumbing services, including backflow protection, leak detection, drain repair, and drain cleaning together with AC and heating installation, maintenance, repair, and indoor air quality solutions. Call to schedule a visit with one of our experienced plumbers to evaluate your home’s current backflow prevention measures to ensure they’re working properly.
