Whether you plan to install your own sewer pipes or you’re wondering if you might damage them, you may need to know how deep technicians bury sewer pipes.
There are certain regulations that sewer companies need to follow to be compliant with the county.
A lot of calculation also goes into the depth of the sewer pipe to ensure it slopes the correct amount to reach the main sewer line.
We dug up everything you need to know about how deep sewer pipes are.
How Deep Are Sewer Pipes? (Full Breakdown)
Private and public sewer pipes each have their own depths.
Private sewer pipes have a broader range of depth than public sewer pipes.
For private sewer pipes, the average depth is between 18 inches and six feet.
Sewer companies may bury them deeper than six feet if the climate has frequent cold temperatures.
There are a few regulations for public sewer pipes.
They’re buried at least 12 feet deep.
Private sewer lines gradually become deeper as they extend past your house.
This is because they need to connect with the main sewer line at the road.
Main sewer lines can be 10 feet or deeper.
Your public sewer line may start shallow, but it progressively becomes deeper as it reaches the main sewer line.
The minimum depth a public sewer can be is one foot.
It’s also important to know that you cannot bury certain types of sewer pipe materials under heavy structures like buildings.
Some can’t even be close to a building.
Standard regulation requires sewer pipes to be two feet away from any building.
If you do want to bury a sewer pipe under a building, then you need to use a material that can support the weight and pressure.
How To Determine How Deep Your Sewer Line Needs To Be
There are a few aspects you should keep in mind to help you determine how deep you need to bury your sewer line.
Keep these things in mind to ensure you install the sewer line the correct way.
Failing to do so can result in a sewer line that could be damaged and pose a health risk.
Also, if the county discovers that the sewer line was improperly buried, then you could receive a hefty fine.
1. Type Of Climate
The type of climate you live in influences how deep you’ll need to bury the sewer line.
Colder climates require sewer companies to bury sewer lines below the frost line.
That line can vary from climate to climate.
In warmer climates, the frost line may be closer to the surface because it takes less time to thaw the ground.
The temperatures are never cold enough to set in a deep freeze.
In colder climates, however, the frost line may be deeper.
As the temperature drops, the water in the soil starts to freeze.
Over time, the freezing temperatures permeate deeper and deeper.
It freezes everything in its path.
Your sewer lines can also freeze if they’re made of metal.
Understanding your climate will tell you how deep you need to bury the sewer line.
Consider your winters.
Are they mild or frozen?
If they’re frozen, then you should bury your sewer line deeper to avoid the frost line.
This may be as shallow as six feet, but it could be as deep as 10 feet.
Do a little research in your area to determine the location of the frost line.
2. County Regulations
Your county will also have regulations about how deep you need to bury the sewer line.
These regulations consider the frost line, other soil conditions, and health hazards.
Before you bury your sewer pipes, contact the proper authorities to understand the minimum and maximum depths for sewer pipes.
You can also receive information about the main sewer line and its location and depth.
Counties will also help you determine how wide your trench needs to be for the pipe.
3. Location Of The Main Sewer Line
The final factor to help you determine how deep to bury your sewer pipes is the location of the main sewer line.
Your sewer pipes need to slope towards the main sewer line.
To determine how much slope you need to create, you need to know the depth of the main sewer.
Otherwise, you could spend days digging around trying to find it.
Main sewer lines run through the street.
They’re usually at 10 feet below the surface, but they can sometimes be deeper.
Once you know the depth and location of the main sewer, you can figure out the slope that you need to allow your sewage to easily slide through the pipe and reach the main sewer.
With that slope in mind, you can figure out the minimum depth that you need to bury your pipes.
How To Find Your Sewer Line
You may need to know how deep your sewer pipes are because you want to find them.
The sewer pipes may need repair, or you may want to remove a clog.
Knowing how deep they are can help you plan your digging.
If they’re shallow enough, then you may be able to dig with your shovel.
If they’re very deep, then you may want to consider renting a digger to make the job easier.
Use these tips to help you find a sewer line and its depth.
1. Call The Previous Owners
If the home is pre-owned, then you can contact the previous owners.
They’ll know where the sewer line runs and may be able to remember how deep it is.
You can find contact information for the previous owners on the deed of the house as well as on past tax records for the house.
One option is to video call them and walk them through the back of the house.
They’ll be able to visually show you the location of the sewer pipes.
2. Contact The County’s Office
When any sewer work happens, the county office receives a record of it.
You’ll find installation and repair reports at your local county office.
Those records can tell you the location of the sewer pipes and their depth.
The county office may even be able to tell you the information about the company that installed the sewer pipes.
You can then contact that company to see if they have any other records that can help you find the pipes.
3. Ask Neighbors
There’s always a chance that your neighbors hired the same sewer company to put in their sewer.
If that’s the case, then they may be able to give you an approximate location of your sewer based on their own.
They may even remember when the sewer was being installed and be able to tell you its location.
4. Look For The Main Drain
Another way to find your sewer pipes is to first find the main drain in your home.
This is the drain where all pipes connect in your home before exiting to the sewer or septic tank.
You can make finding the main drain easier by starting with a fixture.
Then open up the wall and trace the plumbing to the main drain.
Once you’ve located the main drain, go outside.
Find the main drain on the outside of your home.
Then start digging downwards.
It will eventually lead to the sewer line.
From there, you can keep digging until you reach the sewer pipe that needs repair.
Otherwise, you know the location of the sewer pipe.
5. Use A Pipe Detector
A pipe detector uses a transmitter and receiver to trace a line of pipes.
Pipe detectors are not submergible, so you should never submerge them in water.
Instead, choose a sink and remove the stopper.
Then insert the transmitter inside of the pipe.
It will dangle within the pipe.
Take your receiver and head outside.
With the receiver, walk along the yard and slowly move the receiver over the ground.
When it picks up on the signal from the transmitter, you’ll receive a notification.
Mark this area.
Then continue to pass the receiver over the ground.
Keep marking the area with each signal that’s given.
Once the receiver picks up the pipe all the way to the main sewer line or the septic tank, you can start digging.
Begin at the first mark that you made.
Dig down until you reach the sewer line.
If it isn’t there, then try the next marked area.
Once you find the sewer line, you can continue to dig and follow its path.
You can also tell if the detector is working by looking at the marked areas before you dig.
Do they form a straight line?
If so, then you’re likely marking the sewer pipe.
If not, then the detector may be picking up something else.
6. Metal Detector
The final way to find sewer lines is to use a metal detector.
This method only works if you have metal sewer pipes.
Turn the metal detector on and slowly run it across your lawn.
Since it will detect anything metal, you’re going to have a few false positives.
The key to finding your sewer pipes is to find an area that gives you a continuous reading.
This indicates that there’s a lot of metal in the area.
If the signal continues down a line, then it’s likely the sewer pipes.
Mark the area and start digging to see if you’re right.
How Deep Are Main Sewer Lines?
Most cities build their sewer pipes 18 feet below the surface.
Some cities bury their sewer pipes 10 feet below the surface.
Contact your local city or county to determine how deep their sewer pipes are.
Do You Need To Put Your Sewer Pipe Straight?
Sewer pipes should run straight whenever possible.
Adding in curves or sharp angles can decrease the efficiency and effectiveness of the pipe.
When a sewer line has a curve or sharp angle, it makes it difficult for solid waste to get past that curve.
The solid waste needs to change direction.
The only way that it can do that is with water pushing against it.
If too much solid waste collects in a corner or curve, then it can create a serious clog.
Most sewer lines will have a curve or bend of some kind.
Not all homes can have a sewer line that runs straight from the main drain to the main sewer line.
Limiting those curves and angles is ideal.
Besides limiting curves and angles, you need to slope your pipe as straight as possible.
Plumbing code requires that sewer pipes have a slope of at least 1/4-inch per foot.
The maximum slope is three inches per foot.
Too gradual of a slope makes it impossible for solid waste to slide down the pipe.
Too steep of a slope can make the water run faster than the solid waste.
When that happens, there isn’t enough water to push the solid waste down the pipe.
Clogs happen as a result.
One common practice that some sewer companies will follow is to run a minimal slope down from the home.
Then they’ll let the pipe run vertically if the distance is short enough from the top of the pipe to the main sewer line.
Depending on the depth of the main sewer line, you may need a mild or steeper slope than you originally planned.
Top Problems Of Sewer Pipes That Aren’t Dug To The Right Depth
Here are a few problems you may encounter if the pipes don’t reach the correct depth for your area.
1. Freezing Pipes
One of the most serious problems you’ll face is freezing pipes.
If a sewer line isn’t buried deep enough, then it will be susceptible to freezing.
Water in the pipe can freeze and become solid.
This can block solid waste from moving down the pipe to the main sewer.
A clog forms.
If the clog isn’t removed, then the pressure inside of the pipe continues to build until the pipe bursts.
Not only does the sewer pipe need replacing, but you also have sewage spreading through your yard.
Your home can become a biohazard.
It’s important that you bury your sewer pipes below the frost line.
2. Foul Odors
One of the benefits of burying sewer pipes deep in the ground is that it prevents sewer odors from rising to the surface.
If your pipes are too close to the surface, then you may have a regular sewer smell in your yard and home.
Shallow sewer pipes have less soil to filter out the odor of sewage.
As a result, those toxic fumes rise above the surface and can even travel into your home.
Bury the sewer pipes deep to reduce the odor from the sewage.
3. Damage From Heavy Machinery
One final problem that sewer pipes that aren’t buried correctly can face is damage from heavy machinery.
When you run heavy machinery over the area, the weight and pressure can damage sewer pipes.
Certain materials, like clay, are particularly vulnerable to damage.
When you bury sewer pipes at their correct depth, you can drive heavy machinery over the area.
The weight is evenly spread through the layers of soil and rock.
Standard sewer pipes are up to six feet in depth in your yard.
Certain conditions may increase the depth they’re buried.
Knowing how deep the main sewer is can give you an idea of the depth of your own sewer pipes.
Follow these tips to properly bury your sewer pipes and avoid some of the top problems listed above.