The beauty of backflow prevention

houses on a hill connected to a municipal sewer to illustrate backflow prevention and backwater valves

The beauty of backflow prevention

Using a backwater valve to protect your home from sewage backups

On the scale of plumbing emergencies, sewer backups rank toward the top of the list. Human waste flowing into your home and living space is truly a bad situation. If this has happened to you, know that you’re not alone in the problem. This month, our own home suffered from this unfortunate disaster. While I was at work, the sewer main servicing our neighborhood became clogged. Unfortunately, my house was the next down the line from the blockage, resulting in the rerouting of all of my neighbor’s sewage into my basement. Thankfully my wife was at home and noticed the issue. I was able to get home and plug our basement toilet to stop the community’s sewage from flowing into our home any further. If you’re also a veteran of basement sewage cleanups, you may wonder how to prevent it from ever happening again. We don’t blame you. Maybe you’ve never experienced this sewer problem and never want to. We don’t blame you either.

So how can you prevent sewage from backing up into your home? A backwater valve is crowned king for this cause. Before we get into the details of how to use backflow prevention systems to stop sewage backups, lets first develop a solid understanding of how your home’s sewer system works.

How Plumbing Works

The golden principle that all plumbing hinges on is gravity.  All water flows downhill, that is, until something stops that flow.  When the path of water is blocked, the water level rises. If you were to pour water into a funnel, it would continue to flow through that funnel unless you started pouring faster, overwhelming the opening in the funnel.  The water would also overflow if the opening of the funnel became clogged. The same rules apply to your sewer. If there is a full clog or even a partial blockage, water can no longer drain out at the speed required.  At this point the water level rises. This rising water level will start exiting the pipe at the lowest open drain. If you have a basement, this would be a basement toilet, shower, floor drain, or laundry sink. If your home is built on a slab or over a crawlspace, that means that your sewer would backup through all of those same fixtures but on the first floor of your home!!!

What does a sewer backwater valve do?

Most plumbing drain pipes technically function like two way streets that are used primarily as one-ways.  However the potential for something to head in the wrong direction exists. A backwater valve makes your drains like a “one way only” street.  This ensures that waste water can only flow in one direction – exit only!

A backwater valve has a flap inside that opens when water needs to leave your home but closes when water tries to enter your home.  This prevents backups in both your sewer line and in the municipal sewer main from entering your home. It is a great feature to add to your home’s plumbing.

backwater valve in standard open position with flap down allowing water to flow outbackwater valve with flap in active closed position preventing sewage from flowing in

Where is a backwater valve installed?

A backflow prevention device should be installed after all interior plumbing fixtures.  This prevents waste water from backing up into your home at all. The installation location of a backwater valve is usually close to your foundation wall where your sewer leaves your home.

Who needs a backwater valve on their sewer?

Really, anyone could benefit from a backwater valve being installed in their home.  The peace of mind this simple fixture instills is unrivaled. Still, backwater valves are an especially fantastic investment if:

  • you are the lowest house in your neighborhood
  • you have neighbors uphill from you
  • you have a finished basement
  • you have a basement bathroom
houses on a hill connected to a municipal sewer to illustrate backflow prevention and backwater valves

If backflow prevention stops things from coming in, what happens to what you’re draining inside?

The real benefit of a backwater valve is that it prevents problems that may be happening off of your property from creating disaster level backups inside your home.  As mentioned above, if your home is the lowest on the street or downhill from any neighbors, there is the potential that a clogged sewer main will start to backup into your house.  This can happen even if you aren’t using any water. If anyone uphill from you uses their water, the waste will continue to backup into your home until the clog is cleared. In short, a backwater valve keeps sewer water that is out of your control from flooding your home.

It’s important to note that while the backwater valve’s flap is activated and keeping wastewater out of your home, that also means that it is preventing water from leaving.  Any water you send down the drain while the valve is closed will backup into your home’s building drains. This may sound counterintuitive, but we encourage you to consider the situation that this would occur in.  Simply put, you can control the water that you use in your home, but you can not control your neighbors’. A backwater valve keeps your neighbors’ uncontrollable sewage from entering your home, but also prevents you from using your plumbing for the short time while the valve is closed. You would not want to use your plumbing until the clog was removed and everything begins to drain again.  The only water that will backup into your house while a backwater valve is closed is water you personally send down the drain.  

A backup of your personal wastewater with a backwater valve installed is much more manageable than the damage incurred without one.  We have seen basements flooded chest deep with public sewage. Backwater valves are a powerful tool for limiting the potential for damage to your home and family’s health.

The cost of having a backwater valve installed

Like most additions to your home’s plumbing, the cost of having a backwater valve installed fluctuates depending on the nature of your home and what is required.  A backwater valve can be installed for as little as $1,200.  If your sewer line exits your home above your basement floor, less work and equipment is required than if your sewer line is buried under your concrete basement floor.  Factors like this dictate the final pricing of a backwater valve installation.

Would backflow prevention be beneficial for my home?

You may be curious if any backflow prevention techniques would benefit your family’s home.  We would be happy to offer you a consultation on the matter. C.A. Taciak & Sons can perform a backwater valve installation for you if you are eager to protect your home from sewage backup emergencies!