Imagine that a heavy rainstorm comes through your neighborhood.
As the rain falls, you start to notice that the water level in your basement is rising.
Suddenly, something you never thought would happen does: sewage water starts to flow back into your home.
It is a nightmare situation that can happen to anyone, but a backwater valve can stop it from happening.
As an engineering student or engineer, you know that it is important for any drainage system to stop backflow.
So, in this article, I will go over everything you need to know about backwater valves, including how they work, where they are installed, and why they are so important for protecting your home from the unthinkable.
Introduction to Backwater Valve
Formal definition:
A type of check valve in a drainage pipe; reversal of flow causes the valve to close, thereby cutting off flow.
What is a Backwater Valve?
A backwater valve is a device that is attached to a sewer line and keeps water or sewage from flowing back into a home through the drain pipes.
This is called backflow.
It is made so that water and waste can only flow out of the house.
The valve has a flap or gate-like part that lets water leave the house but closes to stop water from coming back in.
When do you need a backwater valve?
Backwater valves are needed on properties where the drain of the lowest plumbing fixture (bathtub, shower, etc.) is lower than the top manhole of the public sewer.
Some building codes and rules may make sure that this is done.
In order to protect these properties even more, they need a backwater valve in their drain line.
Why should you put in a backwater valve?
With a backwater valve, plumbing systems will not overflow during floods, and sewage will not get into basements or bathrooms.
When there is a lot of rain all at once, it can flood the sewer lines and send water or sewage back toward homes.
If the main sewer line gets too full, water or sewage can not get into homes through a backwater valve.
Maintenance of Backwater Valves
It is important to remember that if you have a backwater valve, you need to check it often to make sure it is always working right.
Backwater valves are easy to damage or stop working because of things like root-cleaning machines, debris in the drain line, or other problems.
Limitations of Backwater Valves
When installed and maintained correctly, a backwater valve can protect against backflow.
However, it can not protect your home completely if floodwaters are coming closer and closer.
So, it is important to take extra steps to protect your home during floods, like putting sandbags around it or lifting up important items.
Rebate Programs for Installing Backwater Valves
Some cities have rebate programs for homes built before a certain date that have backwater valves installed.
Some of the costs of putting in a backwater valve may be covered by these programs.
Check with your local government to see if there are any programs like this in your area.
Prevent Sewage Backup: Why Installing a Backwater Valve is the Smartest Move You Can Make
Still hard to understand? Let me change the point of view a bit:
Want to do something fun on the weekend? Install a backwater valve in your drainage system so that when it rains hard, your basement stays dry while your neighbors have to wade through sewage.
Because who would not want a device that stops your sewage flow and makes them the coolest kid on the block? Even though it sounds funny, a backwater valve is an important part of any drainage system, and it could help you avoid a disaster.
Okay, that was just a joke made to look like a TV ad.
Now let's go back to the explanation.
How Backwater Valve Works
Types of Backwater Valves
There are different kinds of backwater valves, and each kind is made to work in a certain kind of drainage system.
The Plumbing & Drainage Institute says that there are six basic types of backwater valves:
- Horizontal backwater valve - designed for horizontal drain lines.
- Vertical backwater valve - designed for vertical drain lines.
- Automatic backwater valve - uses a float or pressure sensor to detect water and close the valve.
- Manual backwater valve - requires someone to physically close the valve.
- Inline check valve - can be installed in an existing pipe.
- Exterior backwater valve - can be installed outside of the building.
How a Backwater Valve Works
A backwater valve is meant to keep water from coming back into homes through drain pipes.
It does this by only letting water or sewage flow out of the house.
The flap, gate, or gate-like part of the valve is usually open.
This lets water leave your home and sewer gases escape.
On each side of the flap, there is a small float inside the valve.
If water or sewage starts to flow backward into the house, the floaters cause the flap to lift up and close.
This keeps sewage from backing up into your basement.
Backwater valves are usually turned on when wastewater flows in the wrong direction.
This can happen when it rains a lot and the city sewer lines get too full, or for other reasons like a clogged or damaged sewer line or a broken sump pump.
Without a backwater valve in the right place, sewage could get into the house through the toilets, showers, etc.
Benefits of a Backwater Valve
The main benefit of a backwater preventer is that it keeps water from coming back into your home from a city sewer or drainage system.
This helps keep the environment you live in and the water you drink safe for your health.
Backwater valves help keep waste water from getting into your home and causing expensive damage to your property.
Installation and Maintenance
Install a backwater valve on the main sewer line near where it leaves your house.
It can also be put on the branch line in the basement to protect all of the fixtures that are below grade.
The valve should be easy to reach and in the right place on the main drain.
Sometimes it is hard to find that spot the first time, and a plumber has to break up concrete or dig in your yard to find it.
When a fixture is put in a floor that is below the next upstream manhole, plumbing codes say that backwater valves must be installed.
The City of Ottawa's building and plumbing code says that backwater valves must be put in every new single-family home, semi-detached home, row home, and townhome.
Some insurance companies may also ask for them to be put in.
Depending on where the city sewer lines are, the valve may be in either your front or back yard.
Cost of Installing a Backwater Valve
The cost of installing a backwater valve depends on a number of things, such as how hard the work is, the size and style of the system, and whether it is a new home or an old one that is being fixed up.
HomeAdvisor says that putting in a backflow preventer costs an average of $300.
But the real costs of the project range from $135 to $1,000, depending on the size and style of the system you choose.
The cost of labor for this job ranges from $100 to $400.
If you need to make changes to pipes that are already there, the labor can cost anywhere from $150 to $400.
Angi.com says that installing a sewer backflow preventer in your home costs around $300 on average.
But due to labor costs, you could end up paying between $600 and $800 (or more) if a lot of work needs to be done.
According to Renshaw.com, the price to install a backwater valve on a sewer line can be anywhere from $750 to $4500 or more.
The price depends on a number of things, such as the difficulty of the installation work, the location, and the type of valve that is installed, among other things.
It is important to remember that if this project needs a permit in your town or county, it will cost at least $50 more.
Mass.gov says that a plumber or contractor will charge about $1,400 to install a combined gate/flap backflow valve or about $600 to install a flap backflow valve.
Maintenance of Backwater Valve
At least once a year, a backwater valve should be checked to make sure it is working well.
Checking the valve for debris that could clog it and making sure all the moving parts can move freely is important.
Most valves have a top plate that is easy to take off.
This lets you see if the water is flowing freely or if something is blocking it.
If you have a backwater valve, you should make sure it works.
Your basement may be flooding because of a backwater valve that has not been kept up well.
Close the valve, wait a few minutes, and then open it to see if the backwater valve is working.
If your backwater valve is working right, you will be able to see water on the ground near your home's foundation.
The backwater valve is working right if there is no water on the ground.
It is also important to clean and check your backwater valve assemblies on a regular basis.
This will help make sure they work properly and keep your home from flooding from sewer backups.
It is important to know that not all backwater valves have a top plate that can be easily removed to check for debris or to make sure that all moving parts can move freely.
Some backwater valves may need to be maintained by a professional plumber.
Comparison with Check Valve
Backwater valves and check valves are both one-way valves that keep liquids from flowing backwards in a closed system.
But they are meant to be used and applied in different ways.
Check Valves
A check valve is made to stop liquid from flowing backwards in a closed system, like a pipe, so that it does not get into the clean water supply.
It is often used in the plumbing industry to stop sewage from backing up into a building.
There are different kinds of check valves, such as:
- Swing type: This type of valve uses a hinged flap that swings open in one direction to allow fluid to pass through, and closes to prevent backflow.
- Lift type: This valve lifts a disk to allow fluid to flow in one direction, then drops to block reverse flow.
- Dual plate type: This type of valve uses two plates to open and close, providing better sealing than the swing type.
- Stop-check valve type: This valve is used to stop the flow of fluid in either direction.
Backwater Valves
A backwater valve, which is also called a backflow valve or sewer backup valve, keeps the sewage line from flooding or backing up when it rains hard or when the sewer backs up.
It keeps backflow from happening in homes and businesses that are connected to public sewer lines or private septic systems.
There are different kinds of backwater valves, such as:
- Flapper type: This type of valve has a flap that allows water to flow out of the house but closes to prevent backflow into the home.
If water or sewage starts to flow backward into the house, the floaters cause the flap to lift up and close.
This keeps sewage from backing up into your basement.
- Ball float automatic knife type: This type of valve uses a ball float to detect water and a knife gate to close the valve when needed.
When the water level goes up, the ball float moves up.
This moves the knife gate, which then closes the valve.
Comparison
In summary, check valves are used to keep liquids from getting into the clean water supply, and backwater valves are used to protect the sewage line from flooding or backups caused by heavy rain or sewer overflow.
The most important differences between backwater valves and check valves are:
- Intended use: Check valves prevent liquid contamination of a clean water supply, while backwater valves prevent sewage backups and flooding.
- Application: Check valves are typically used in plumbing systems, while backwater valves are installed in the basement close to where drain piping exits homes or on the main sanitary sewer close to where it leaves your house.
- Types: There are different kinds of check valves, such as swing type, lift type, dual plate type, and stop-check valve type.
There are also different kinds of backwater valves, such as flapper type and ball float automatic knife type.
Before installing either valve, homeowners should talk to a licensed professional because each one is used and needs to be used in a different way, depending on the situation.
How Backwater Valves work, Basic Principles
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Use cases
| Used in: | Description: |
|---|---|
| Residential Properties: | Backwater valves are often used in homes to keep sewage from backing up into the house during heavy rainstorms or flooding. They are put in the main sewer line to stop sewage water from flowing back into the home's drainage system. Backwater valves are especially helpful for homes in low-lying areas or in places with bad drainage. |
| Commercial and Industrial Properties: | Backwater valves are also used to prevent sewage backup and water damage in commercial and industrial buildings. They are put in the main sewer line to stop waste water from going into the building's drains. Backwater valves are especially helpful in places with high water tables, bad drainage, or a lot of water use. |
| Municipal Infrastructure: | Backwater valves are an important part of city infrastructure, especially in areas that often flood or get a lot of rain. They are put in the main sewer line to keep sewage from backing up and to protect roads, buildings, and public utilities from getting damaged by water. |
| Stormwater Management: | In stormwater management systems, backwater valves are often used to stop the flow of dirty stormwater into clean water sources. They are put in place at the stormwater outflow to stop dirty water from flowing back into the clean water system when it rains a lot. |
| Wastewater Treatment Plants: | Backwater valves are also used in wastewater treatment plants to stop dirty water from flowing back into the system. They are put in the outflow of wastewater to stop dirty water from flowing back into the treatment system during heavy rainstorms or flooding. |
Conclusion
In conclusion, a backwater valve is a small but powerful device that can stop a disaster that could damage your property and cost you thousands of dollars to fix.
As a student of engineering or an engineer, you know that it is always better to prevent problems than to fix them.
With a backwater valve in your drainage system, you can rest easy knowing that even in the worst case, your home is safe.
As weather events keep getting more frequent and severe, it is more important than ever to take steps to stop backflow.
So, the next time you think about home maintenance, think about installing a backwater valve as an important investment in the safety of your property.
Remember that it is always better to be safe than sorry when it comes to stopping backflow.
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