What is a Sewer Main Drain? Everything You Need to Know About Main Drains

In this blog post, you’ll read:The sewer main drain is an essential part of the household plumbing system. The drain is often neglected as it is not apparent. It lies under the ground and serves the central function. The main drain needs regular maintenance.

Table of Contents

The sewer main drain is an essential part of the household plumbing system. The drain is often neglected as it is not apparent. It lies under the ground and serves the central function. The main drain needs regular maintenance. It might show initial signs of a clog or other problems. You must pay heed and get a quick solution to save expensive repairs. Here is a complete guide on sewer main drains.

MSDGC – Building Sewer Responsibility

Building Sewer Responsibility

What is a Sewer Main Drain?

A sewer main drain is an underground pipeline that exits a building’s sewage. It is a large and wide pipe consisting of durable material. It takes wastewater from bathrooms, toilets, etc., and drains them into the city’s sewer line. It is a crucial component of a city’s sanitation infrastructure. The main drain ensures all sewage is taken to treatment facilities.

Sewer Main Drain

The material of Sewer mains is durable, like concrete, iron, or plastic. They range in diameter from 6 inches to over 12 feet. They are underground and are present beneath city streets, alleys, or public rights-of-way. The sewer main connects to smaller pipes, known as lateral pipes. They carry wastewater from individual buildings to the main sewer line.

Sewer mains rely on gravity to move wastewater downhill to the treatment plant. They have a slight downward slope to ease the flow of water. Sometimes, we use pumps to help move wastewater through the pipes. The sewer main drains have a cleanout in houses. It provides easy access to maintain the plumbing system.

How to Locate a Sewer Cleanout?

Locating a cleanout is essential to identify defects in main drains. It provides a passage to sewage from the house toward the municipal drain. Besides, sewer cleanout is a connection to the main sewer drain. Locating a cleanout means finding an inlet of the main drain. Here is a guide on how we can identify cleanouts in our houses.

Locate a Sewer Cleanout
  • Check Your Plumbing Plans: 

If you have access to the plumbing plans of your home, you can check them. They can help you find the cleanouts. The plumbing plans often show the location of the cleanout, which can help locate it.

  • Look For a Pipe With a Cap:

The main drain cleanout is often present near the perimeter of your home. A pipe extends vertically from the ground with a cap on top. Look around the edge of your home for a pipe that matches this description.

  • Check Near the Foundation: 

The main drain cleanout can be near the foundation of your home. Check the area around the foundation for the cleanout.

  • Check the Basement or Crawl Space: 

Check for a cleanout near the sewer line if your home has a basement or crawl space. It may lie on the floor or wall.

  • Look For a Cleanout In the Yard:

If your cleanout is not in your home, you may find it in the yard. Look for a pipe with a cap in your yard, particularly near the perimeter of your home.

  • Use a Sewer Camera: 

If you’re having trouble locating the cleanout, a professional plumber can help. They use a sewer camera to find the cleanout. A plumber can also identify any potential issues in your plumbing system.

Once you have found the cleanout, it’s essential to keep it accessible. It should be clear of obstructions to allow for easy maintenance.

  • Signs of Clog in Sewer Main Drain: 

A clog in the sewer main drain can cause several signs of a problem. Here are some clear signs that indicate a clog in the sewer main drain:

Slow Draining: Clogs make wastewater hard to drain. It could be showers, sinks, or tubs. Clogs result in slow draining or no drawing at all.

Toilet Backup: Clogs in the main drain in the toilet overflow. It can also result in a slow toilet drain. These are potential signs of sewer clogs.

Clog in Sewer Main Drain

Foul Odors: If you notice a foul odor coming from your drains or your yard, it could be a sign of a clog in the main sewer drain.

Gurgling Sounds: gurgling sounds from the toilet, sink, or shower drain can indicate a clog in the sewer main drain.

Sewage Backup: Sometimes sewage backs into your home through a floor drain or a lower-level bathroom. It could indicate a severe clog in the sewer main drain.

Wet Spots or Sinkholes In Your Yard: Clogs cause wet spots or sinkholes in your yard. It is a sign that the sewer main drain is causing water to back up and seep into your yard.

If you notice any of these signs, taking action immediately is vital. It will prevent further damage to your plumbing system. A professional plumber can help you identify the location of the clog and clear it. Regular sewer line maintenance can also help prevent clogs in the first place.

How to Fix Clogs in Sewer Main Drain? 

Fixing a sewer main drain clog can be a challenging task. It’s essential to take immediate action to prevent further damage to your plumbing system. Here are some steps to fix a sewer main drain clog:

Identify the Location Of The Clog: 

The first step in fixing a sewer main drain clog is to identify the location of the clog. You can do this by checking all the drains in your home. Observe the clogs in drains. The clog is likely in the main sewer line if you find clogs in all drains.

Turn Off the Water Supply: 

Once you identify the location of the clog, turn off the water supply to your home. It will prevent any additional water from flowing into the clogged sewer line. It can save from causing further damage.

Clear The Clog: 

Below are several methods to clear a sewer main drain clog.

  • Plunge the Toilet: If the clog is near the toilet, you can use a plunger to dislodge it. Before you start, put on a pair of rubber gloves to protect your hands from any germs. You may also want to lay down some newspaper or old towels around the toilet to catch any water that may splash out.
Clear The Clog

Place the plunger’s rubber cup over the toilet drain, ensuring it forms a tight seal. The rubber cup should completely cover the drain opening. Add enough to cover the plunger cup if the toilet bowl has no water. It will create a vacuum seal when you start plunging.

Now begin plunging up and down rapidly. Use a solid and steady force.  Avoid using excessive force as it can damage the toilet. The aim is to create suction and pressure to dislodge the clog.

If the water begins to drain, flush the toilet to see if the clog has been out. If not, repeat the plunging process until you remove the clog. Once you do it, flush the toilet several times to ensure the water drains correctly. Remove the gloves and clean the plunger and surrounding area with soap and water.

  • Use a Drain Snake: A drain snake is a long, flexible tool that we can insert into the drain to clear the clog. Put gloves on your hands and eyewear. Insert the snake into the drain. Push it in as far as it will go. If you use a hand-crank snake, turn the handle clockwise to move the snake through the pipe. If you are using a power drill snake, turn on the drill to rotate the snake through the pipe.
Drain Snake

 You will reach the clog when you feel resistance or hear a change in the sound of the snake. It may take some time and effort, but be patient. Move the snake back and forth to break up the clog. Apply gentle pressure to avoid damaging the pipes.

Once you have broken the clog, slowly remove the snake from the drain. If you encounter resistance, move the snake back and forth until it is free. Flush the drain with hot water to help clear any remaining debris. Clean the snake with soap and water, and dispose of any waste in a trash bin. Remove your gloves and protective eyewear and clean the surrounding area.

  • Hire a Professional Plumber:  Sometimes, the clogs can be severe. Hiring a professional plumber is best if you don’t know how to clear the clog. They can use special equipment to clear the clog, such as a hydro jet or a sewer camera.

Inspect the Sewer Line: 

Once the clog is evident, inspect the sewer line for any signs of cracks or leaks. If you notice any damage, it’s best to contact a professional plumber to repair it.

Prevent Future Clogs: Use preventive measures to prevent future sewer main drain clogs. Avoid flushing non-degradable items. It includes paper towels, solid waste, or wipes. Also, consider having your sewer line inspected. Clean it on a regular basis to prevent clogs.

How to Prevent Clogs in Sewer Main Drain?

Preventing sewer main drain clogs is essential to maintain a functioning plumbing system. Here are some detailed tips to prevent sewer main drain clogs:

  • Dispose of waste properly: 
Dispose of waste properly

You should only flush toilet paper down the toilet. Avoid washing non-degradable items such as paper towels, hair, or wipes. It’s better to install sink waste drainers. These items do not break down and can quickly lead to clogs.

  • Avoid Pouring Grease Down the Drain:

Grease and oil can quickly solidify in your pipes. It leads to clogs. Instead, dispose of grease and oil in a sealed container and throw them in the trash.

  • Install Drain Covers: 

Install drain covers on all of your drains. It prevents hair, food scraps, and other debris from entering your pipes.

  • Regular Cleaning of Drains: 

Regularly clean your drains using a plunger or a drain snake. You can also use baking soda and vinegar to clean your gutters naturally.

  • Inspection of Sewer Lines:  
Inspection of Sewer Lines

Hire a professional plumber to inspect your sewer line. They use equipment to identify clogs or blockages before they become a problem.

Install a Backwater Valve: 

Install a backwater valve to prevent sewage backups during heavy rainfalls. A backwater valve stops sewage from flowing back into your home.

Don’t Plant Trees Near Your Sewer Line: 

Sewer Line

The roots of trees can infiltrate your sewer line, which leads to clogs. If you have trees near your sewer line, consider removing them. You can also install a barrier to prevent root infiltration.

Preventing sewer main drain clogs requires diligence and maintenance. Following these tips can reduce the risk of clogs and keep your plumbing system working.

Difference Between a Main Drain And a Sewer Line:

A main drain and a sewer line are parts of your plumbing system. They are responsible for the disposal of wastewater. However, there Are some critical differences between the two. Here’s a detailed explanation of the differences between a main drain and a sewer line:

Main drain and a sewer line
Properties.Main Drain.Sewer Line.
Definition.The main drain is the primary drain line. It carries wastewater away from your home to the sewer or septic system.On the other hand, the sewer line is the pipe that carries wastewater from your house to the public sewer system or septic tank.
Location.The main drain is located inside your home. It is connected to all the other drain pipes in your home. It carries wastewater from your sinks, toilets, showers, and other fixtures to the sewer line.The sewer line is located outside your home. It carries wastewater from your property into the public sewer system or septic tank.
Size.The main drain is often a larger diameter pipe than other drain pipes in your home. It usually measures 3 to 4 inches in diameter.The sewer line, however, is a much larger pipe. It measures 4 to 6 inches or more in diameter. Its design is so to handle larger volumes of wastewater.
Responsibility.The main drain is the responsibility of the homeowner. It means that if there is a problem with the main drain, the homeowner is responsible for fixing it.While the sewer line is the responsibility of the local government or utility, when there is a problem with the sewer line, the local government or utility company is responsible for fixing it.
Maintenance.The main drain requires regular cleaning and maintenance to prevent clogs and backups in your plumbing system.The sewer line also requires regular maintenance. It includes cleaning and inspection to ensure it is functioning correctly and identify issues.


We often neglect the maintenance of main sewer drains. Yet, they are essential to keep our plumbing system efficient. We should use preventive measures to avoid clogs in drains. If a clog still occurs, you can remove it by trying one of the above methods. They are easy ones with minimal effort.

If you don’t fix the drain clogs in time, it can cause problems. A foul odor and toilet backflow are one of the most annoying outcomes. The best remedy is to keep proper check out of main drains. If drains get clogged, remove them in the first place. Consult a plumber if you fail to get desired results.

Ask For A Water Control Solution Now

We do not only provide basin waste, but we can provide solutions for water control.

Get In Touch Now!

*We respect your confidentiality and all information is protected.

× How can I help you?