Whole-House Sewer Clog

clogged toilet

clogged bathroom sink

clogged bathtub drain

clogged kitchen sink





It’s not uncommon.  Yesterday everything seemed fine.  Today every drain is backed up.  What happened?  

A Whole-House Sewer Clog…

  • In many cases, the problem was building over time, and eventually a Whole-House Sewer Clog has occurred.  
  • In some cases, the problem happened all at once due to something becoming logged in your home’s main sewer line (from your house to the connection at the Public Sewer).
  • Other cases are due to a failure of the sewer main line, either under the house or in the lawn.

This Article Describes How A Sewer Main Works, And The Typical Reasons A Whole-House Sewer Clog Occurs


Sewer Main Line From House To City’s Sewer Connection

residential sewer lateral to city sewer connection

This Diagram Shows The Underground Private and Public Sewer lines


The common name for the portion of the sewer pipe, from where it connects to the house and where it connects to the city’s Public Sewer, is called a “Sewer Lateral”.   This pipe is private because it serves only your home, and it is entirely the Home Owner’s responsibility.  Clogs, Repairs and Replacements of each home’s private sewer lines are paid for by the Home Owner.  The city is responsible for only the Public Sewer Lines.


How a Whole-House Sewer Clog Is Cleared

When every drain in the house stops working, there is a problem with the main sewer line (sewer main).  The blockage can be in the lawn, or under the house (under the slab).  In most cases, the blockage can be cleared with a drain-cleaning “snake” machine.

sewer drain line auger cleaning machine


This machine will enter the drain line through a plumbing clean-out in the lawn.  If your home does not have one, the auger-line will be inserted into a drain-vent stack on the roof.

Exterior Sewer Clean Out  Sewer Vent Pipes in a roof

Plumbing Clean-Out in the lawn                      Drain-Vent Stacks on the roof


Things You May Be Doing That Cause Whole-House Sewer Clog

(Blockages In Your Private Sewer Main)

Expecting Too Much From A Garbage Disposal

  • Lack of knowledge of types of food waste that can pass through a garbage disposal can create a blocked sewer line.

Always run cold water for at least 2 min. after disposal use, to make sure it everything gets through the drain line. Grind food in small batches, giving the water a chance to move the waste down the drain. Do not attempt to grind fibrous foods such as: coffee grounds, banana peels, onion peel, corn husks, artichoke leaves, breads, and celery for example.

food waste that is not to be put in garbage disposer


Build-Up Of Grease From Cooking

  • Put discarded grease in a sealable container and discard with your trash.

Fats, Oils and Grease (FOG) shouldn’t be poured down the kitchen drain.  The EPA estimates up to 36,000 Whole-House Sewer Clogs occur each year in the U.S., with approximately 1/2 of the backups being grease-related.

If you must put grease down the drain, do it with COLD water.  With cold water, the grease solidifies into “balls” — most of which will be carried to the City’s Sewer Line within the cold water the grease was flushed with.  Never use HOT water.  If you do, the grease will start to solidify on its way to the City Sewer Line — when this happens, the grease will stick to your private sewer pipe as it cools.

sewer main clogged with grease

Sewer Line Clogged With Grease

Flushing Anything Other Than Toilet Paper

Sewer lines are designed to accept only human waste and toilet paper. Do not flush anything else, including the worst offenders: baby wipes, diapers, paper towels, Q-tips, dental floss and feminine hygiene products.

image saying no baby wipes in the pipes

Disposable Baby-Wipes.  Though marketed as “flushable” these wipes have a notorious reputation for a Whole-House Sewer Clog.  Unlike toilet paper (which breaks down rapidly when wet) Baby-Wipes don’t break down fast. After the water from the flush is gone, they can float to the bottom of the sewer pipe.   Once a wipe is at the bottom of the pipe, it provides a place for additional wipes to catch on.

baby wipes demonstration showing they don't break down like toilet paper

This photo shows Toilet Paper broken down in water — while Baby Wipes are still the same as when flushed

For more detail on the problems caused by Baby Wipes, see this article by ABC Baby Wipes Clogging Sewers – ABC News

Foreign Objects Flushed

There are many things which fit through a toilet, but won’t make it to the City’s Public Sewer Line.  Once they land at the bottom of your sewer main, they provide a surface for other things to get caught on, eventually causing a Whole-House Sewer Clog.  While many objects are flushed by mistake, you don’t get a free pass on unclogging the sewer line.

foreign objects that clogged sewer lines

Foreign Objects Removed From Clogged Sewer Lines

Other things make it into the sewer line on purpose.  It’s not uncommon to discover a child flushed something which caused a Whole-House Sewer Clog.  As parents, we tell our kids not to put stuff down the toilet, but sometimes the temptation (to see if it will flush) is simply too much…

foreign objects found in sewer main

Toys Which Were Given “A Burial At Sea”


Problems Which Clog All Sewer Lines (That You Can’t Control)

1. Sludge Build Up

Over time, all sewer mains accumulate sludge.  This is normal and will require cleaning to remove it now and then.  Sludge is a sticky concoction of soap-scum, grease, hair, food particles and dissolved minerals in the water. Once a layer of sludge forms, more sludge tends to accumulate in that area of the pipe, increasingly narrowing the size of the pipe until only a small channel exists.   Once this has occurred, even minor amounts of solid human waste flushed down the toilet can cause a total blockage.

Sludge cannot be prevented, it’s an accumulation of waste that is flushed which does not make it completely out of your sewer line (into the City’s Sewer Line).

sewer main sludge build up

Sludge Build Up

2. Pipe Dislocation In The Line

sewer line dislocated

 DFW is built on expansive-soil.  Expansive Soils Contain Clays Which Absorb Water.

When wet, the clay increase in volume and can exert upward force (from below) on sewer pipes. When dry, expansive clays shrink.  This can cause insufficient support (from underneath) the sewer line. As with home foundations, the movement of the sewer pipe can damage it over time.

While dislocation is common in clay sewer pipes, it may also happen to PVC (white plastic) pipes.   A joint misaligns the sewer pipe from its original position, allowing tree roots to get into the pipework and cause blockages.   Even when trees are not near the pipe, tree roots can reach the pipe from nearby trees (which may appear too far away to cause problems).


Problems Which Clog Private CLAY Sewer Lines (That You Did Not Contribute To)

3. Damage From Tree Roots

beginning of tree roots in sewer pipe  tree roots in sewer pipe  tree roots in sewer

The Three Stages Of Tree Roots Damage:

  • Infiltration (at the connections):  This is common with clay sewer pipes, because they leak a little at the connections.
  • Blockage due to growth of the roots:  Once roots are in, they will continue to grow until they eventually clog the pipe.  Additionally, debris can catch on the roots and cause a clog.
  • Damaged Clay pipe:  Tree roots will get as aggressive as needed to get water for the tree, and can damage pipes.  In dry DFW summers, trees will do what they must to survive.

Tree roots are frequent reason for sewer main clogs and damage.  If you have a home built before 1975, chances are the Sewer Main in the lawn is made of Clay pipe.  Clay pipe last a long time, but is often damaged by tree roots because clay pipes leak a little at the connections, attracting tree root growth.  Sewer main clogs are common where clay sewer pipes are near trees.

Trees are always in search of water and will extend their roots as long as necessary to find it.  If the tree is young, there may be no problems for many years, until its roots grow long enough to reach the sewer main.   It’s a good guide to note that a root’s crown (area with leaves) is roughly the size of its underground root-structure. If you have trees in the area of the lawn where a clay sewer main is located, in time you will likely have sewer main clogs due tree roots damaging clay pipes

NOTE: For homes built later than 1975, PVC (white plastic) pipe was typically used.  PVC seals tightly at the connections and does not attract tree roots.

Clearing The Sewer Line May Temporarily Help With Tree Roots

If tree roots are clogging your sewer line, in many cases a temporary fix is to have the sewer line cleaned.  The machine may be able to cut through root growth (it depends on how big the roots are).   If roots have found a way into your sewer line, and they are removed, they will grow back — how long that takes cannot be determined.

The trees near your sewer line breached the sewer line in search of water.  Watering the trees will reduce the root growth back into the sewer line.  At best, this will slow the root growth and provide more time before a permanent fix occurs.

plumbers snake removing tree roots

Diagram showing sewer cleaning removing tree roots.


Watering Trees Near CLAY Sewer Lines May Help Reduce Root Growth

You may be able to reduce aggressive tree root growth by ensuring the nearby trees are adequately watered.  If enough water is near the tree, the roots don’t have to continue reaching farther out in search of needed water.   One commonly used formula suggests 10 gallons of water (per week) for every 1 inch of tree-trunk diameter.  Always water under the tree crown (the outer limit of the branches).  This encourages the tree not to extend its roots farther.

NOTE:  If your home has PVC (white plastic) sewer lines in the lawn (which is common if the home was built in 1975 or later) you don’t need to worry about tree root growth.   Clay sewer pipes leak a little at the connections — PVC are water tight and won’t attract tree roots.

How To Water Trees

For small to medium size trees, there are dedicated tree soaker-hoses. You can also surround the tree with a standard soaker hose.  NOTE:  This may help your home’s foundation too.

tree soaker hose   tree soaker hose installed  weeper hose in use









New Tree Soaker Hose                                                                         Tree Soaker Hose Installed                                                  Soaker Hose Appearance While Watering


4. Cast Iron Sewer Pipes (under the house) That Failed Due To Corrosion, Creating A Whole-House Sewer Clog

Most DFW homes built before 1970 have Cast Iron Waste Pipes under the slab.   Cast Iron lasts a long time, but eventually fails dust to rust (which begins on the inside of the pipe) and eventually making its way all the way through the pipe.  Depending on the quality of the cast iron installed, these pipes in DFW homes will last 40-60 years before they rust through and fail.  Once this occurs, the pipes are typically replaced.

There are other causes of damage to cast iron that can reduce its life span.  For example DFW’s shifting soils may cause joint breaks and other damage.  When foundations experience movement, it can shift and break these pipes.  Tree root damage can also occur once the pipes start leaking due to rust through.  All of these problems accelerate the deterioration of even a high quality cast iron pipe.

Most homes built after 1975 have PVC (white plastic) waste lines.  PVC does not corrode, and is estimated to last up to 100 years or longer.  Shifting soil and foundation movement can damage PVC pipes as well as cast iron.

cast iron sewer pipe rusted from inside

Cast Iron Pipes Rust From The Inside To The Outside

cast iron sewer pipe rusted through with pinhole leakThe First Signs Of Rust Through Often Look Like This

cast iron sewer pipe rusted through

Eventually, Cast Iron Pipes Rust All The Way Through And Must Be Replaced

Why You Must Minimize Your Home’s Slab Foundation’s Movement

DFW is built on expansive clay soil.  When the clay in the soil gets wet, it increases in size.  This creates an upward pressure on your home’s slab, causing the slab to move upward primarily along the edges and corners.

When the clay dries out, it reduces in size. This can cause insufficient support for the slab and allows it to move downward along the edges and corners.   This diagram is a visual representation of what happens to a home’s slab due to changes in soil moisture-level under the slab.

diagram of slab foundation movement on expansive soils with moisture changes

A slab foundation does not move evenly.   The movement at the edges and corners of the slab is greater than farther toward the center of the slab.  This occurs when the soil around the home becomes too wet and becomes larger -or- dries out and becomes smaller.  The farther toward the center of the slab, the less the soil moisture-level changes.  Since the majority of the changes in moisture-level occur at the corners and outside edges of the slab, this is why the slab’s movement is greater at the edges and corners.

How Slab Movement Damages Water Supply Lines and Waste Pipes

This photo helps you understand why slab movement can break water supply-lines or waste lines.  The horizontal waste pipes are under the slab and run through the soil under the house.  The vertical pipes go up through the slab where they are connected to plumbing fixtures above the slab.

When the slab moves up or down (due to soil moisture-level changes):

  • The vertical waste pipes (attached to plumbing fixtures inside the home) move up and down with the slab.
  • The horizontal waste pipes don’t move (because they are located within soil).
  • If the slab movement is enough, the pipes can crack due to the upward or downward pressure the slab-movement creates on the pipes (in the ground below the slab).
  • Water pipes are also just below the slab and covered with soil.  This creates the same slab-movement problems with water supply-line as waste lines.

NOTE: This same movement is also what creates the need for foundation repairs in DFW.

photo of water pipes coming up from the ground before slab cement is poured

This photo shows both Waste Pipes (white) and Water-Supply Pipes (red & blue) coming out of the ground (under what will be the slab floor when cement is poured)

tunnel under slab to sewer pipes

This photo shows how the sewer-main pipe (largest one) runs through the soil.  It’s exposed in the photo only because of the tunnel that was dug.

One Of The Most Important Maintenance Tasks For Your DFW Home Is To Ensure The Moisture-Level At The Edges Of Your Home’s Foundation Stays Fairly Consistent

The less change in moisture level, the less slab movement, and the less likely you will have: cracked water supply-lines (slab leak), cracked waste lines or foundation damage.

Two Things You Must Do To Minimize Slab Movement Due to Soil Moisture-Level Changes

1. Eliminate Rain Water Falling Off The Roof At The Edges Of The Foundation (to minimize large increases in soil moisture-level).

  • This is accomplished with Rain Gutters to catch and move the water away from the foundation.  Allowing rain water to fall right at the foundation causes tremendous changes in soil moisture-level. The more the moisture-level changes, the more the slab moves.
  • It’s equally important important to have Gutter Downspout-Extensions to carry the water at least 3 feet away from the foundation.

rain gutters installed on a home

rain gutters extension installed on a home






Rain gutters at the roof                           Extensions at the ground.


2. Provide “Foundation Watering” During Periods Of Hot & Dry Weather (to reduce large decreases in soil moisture-level). 

It’s important to “water” the foundation of your DFW home when the soil around the home is too dry (this is mostly during summer).   This reduces the chances of damage to the foundation, water supply lines & waste lines due to slab-movement caused by low soil-moisture around the edges of your home.   Many automatic irrigation (lawn sprinkling) systems are designed to water the foundation (if it was part of the original installation).

For those who don’t have and automatic irrigation system, an easy way to help maintain moisture-level around your home with with Soaker-Hoses connected to Automatic Timers.

weeper hose in use

These hoses add small amounts of water over long periods of time.  This allows the soil around your home to absorb the moisture.

weeper hose

There Are Many Brands Of Soaker-Hoses.  They All Work The Same Way, So Brand Does Not Matter.


water timer for garden hose

There Are Countless Battery-Operated Timers Available For Garden Hoses.  They Connect To A Home’s Exterior Faucets

3. How Long Do You “Water The Foundation”?

If You See A Gap Between The Foundation And The Soil, You Need To Water That Area Of The Foundation.  The amount of water needed changes from side to side of the home due to sun exposure.  East and north exposures are cooler and require less water than west and south exposures.  If the home is elevated above the ground at the foundation, or is on a homesite that’s on a hill, this also affects how much water is needed on each side, as some homesites drain water away better or worse than others.  There are other factors which affect the frequency and quantity of watering needed.

Your lawn will tell you when it’s too dry around the foundation. Walk around your house and look where the soil is against the foundation (you may have to pull back plants or mulch).

  • If you see a gap between the foundation and the soil, you need to water the ground around your foundation until the soil swells and closes the gap.
  • If you do not see a gap between the soil and foundation, your soil moisture is good.
  • Lay soaker-hoses 18 inches away from the foundation.
  • Start by setting the water-timer for 2 hours per day.
  • Check each day for a week to see when the gap closes.  That tells you how many days each week you need to water (at that time of the year).
  • Space the days you need to water over a 7-day period.
  • As the weather gets hotter and drier during the summer, you will likely need to increase the number of days you water.  Once each week, check to ensure the gap in the soil does not exist.
  • The best time to water is at night.  No sun and cooler temps reduces the amount of evaporation.
  • Most (if not all) municipalities allow foundation-watering at any time on any day.  Check your City’s website to ensure you are in compliance if foundation-watering restrictions apply.

gap between soil and foundation means soil is too dry

A Gap Tells You The Soil Is Too Dry

This information is found in the article “Foundation Watering Tips, Texas A & M University”.  Author: Dotty Woodson, Water Resource Program Specialist, Texas A&M AgriLife Extension Service This link takes you to the article:  Foundation Watering Tips, Texas A & M University


The article was designed to educate you about your home’s private sewer line in the lawn, which connects the house to the City’s Public Sewer line.  Also discussed is the sewer main under your home’s slab foundation.  Either of these portions of the sewer lines can cause a whole-house sewer back up.  We detailed what typically causes these clogs and how they are typically cleared.  Also discussed was how older sewer lines are subject to damage, tree root intrusion or degradation of the materials that were used to build the sewer line.

If the material the sewer line was built with fails, it can cause a whole-house sewer line clog.  If the clog is due to sewer line failure, it requires an expensive repair or replacement.  In most cases, the existing sewer line is removed and replaced.  There is nothing a homeowner can do to make the material their sewer lines are made of last longer.  For homes built after around 1975, most homes have PVC (white plastic) sewer lines.  PVC has no history of notable failure, and is currently anticipated to last 100 years or longer.


Al’s Plumbing, Heating and A/C has been serving residents of: northern Dallas County, northeastern Tarrant County, and southern Denton and Collin Counties since 1989.  Al’s Plumbing & HVAC offers 24 /7 Emergency Service, and daytime hours by appointment at your convenience.  Al’s has Service Trucks which are fully stocked with the most frequently needed Plumbing and HVAC System parts, to ensure One-Trip Service in most situations.

Al’s clears Whole-House Sewer Clogs, in addition to individual drain-clearing throughout your home.  Al’s does all residential Plumbing and HVAC System maintenance, repairs and replacements on any brand of Water Heater, Air Conditioner, Heat Pump, and Gas & Electric Furnaces.   Call Al’s today to make an appointment to correct your Plumbing or HVAC System problems.