What is a lateral?

All homes and businesses connected to sanitary sewer systems have a lateral. It's the pipe that transports water used inside your home out to your city's sanitary sewer system in the street (see the pipe highlighted in the picture below).

Just like roofs and driveways, maintaining a lateral is the homeowners responsibility. Some communities require homeowners to repair and maintain laterals from the house out to around the sidewalk or tree lawn, what's known as the right of way. In other communities, homeowners own the lateral from the house all the way to where it connects to the city's sewer system in the street. Check with your city to find out.

Lateral Cut-Away Diagram

How Do Laterals Play a Role in Basement Backups?

Laterals are only supposed to carry water you use in your house out to the city's sanitary sewer pipe. Cracks and leaks in laterals end up allowing too much excess ground water into city owned pipes, which can overwhelm the overall sewer system and cause stormwater and wastewater to backup in the sewer system and into people's basements.

(Above) Crews install a lateral (blue pipe at bottom of the picture) in gravel at the bottom of a trench and a water supply line (copper tubing) at a construction site in the city of Milwaukee.

How Can I Tell if My Lateral is Cracked or Leaking?

If you have ever had to call a plumber to unclog your lateral, you most likely have a leaky lateral. Tree roots are always seeking water and end up growing through cracks in laterals. The roots end up accumulating things that are flushed or poured down the drains in your home, leading to a clogged pipe. You can tell when your lateral is clogged when water backs up into your basement during dry weather. It's the water you used in the home that cannot get out the lateral to the city's sanitary sewer in the street.

You can also check for leaks and cracks by having a plumbing company run a television camera through your lateral. You will be able to see any major problems right away. Identifying smaller cracks may require soaking your front lawn with water and an environmentally friendly green dye. When the camera views green water in the lateral, you know there are leaks in the pipe. (Watch this video to see how it's done). Make sure to get a copy of the video from your inspection. You may want to get a second opinion on any problems that are diagnosed and potential solutions.

Cracked Lateral Drain

How Should I Maintain My Lateral?

You should have your lateral inspected every five to ten years, depending on the age of your home. Newer laterals are made out of PVC, a high-strength plastic that is slightly flexible. PVC pipes for home laterals come in 10 foot lengths and have long lasting, water-tight joints if installed properly. Plumbers started installing PVC laterals in Wisconsin in the 1970's.

Older laterals may be made out of clay pipes that were typically installed in two foot sections. Joints and cracks on clay pipes tend to fail over time, allowing large gaps to permit excess water into the sanitary sewer system.

(Below) A broken clay lateral.

Broken Clay Lateral

FATS, OILS & GREASE - Do Not Pour Them Down the Drain!

Don't pour Fats down the drain Don't pour Oils and Grease down the drain

How Do I Know if a Basement Backup is From Too Much Rain or a Clogged Lateral?

If it's not raining and you get water backing up into your basement through the floor drain, there's a good chance you have a clogged lateral. The water that you used inside your home cannot get through the lateral and empty into the city's sewer out in the street.

Even if it is raining and you have water coming through the floor drain, you could still have a clogged lateral that needs to be cleaned out. When basement backups occur because of capacity issues in the sanitary sewer system, they usually impact more than one home on the block. Contact your city or village department of public works right away so they can check to see if there are any problems with the public sewer out in the street.

What's the Fix if My Lateral Needs Repairs?

There are many newer repair techniques that do not require digging a large trench in your front yard. However, laterals in substantial disrepair may require digging a trench to install a new pipe from the street to the foundation of your home.

Open trench excavation

Open trench excavation

Open Trench

Crews dig a trench down, 6 feet to 16 feet, to your existing pipe, take out the old pipe and lay a new one from your house out to the city's sewer in the street.

Lateral lining method (below) Crews prepare to install a liner, which is the white fabric at the end of the hose.

Lateral lining

Lateral Lining - This technique involves pulling special fabric through your existing lateral that is applied with a resin. Think of it as a big sock that's turned inside out when they pull it into the pipe so the resin is on the outside of the sock. They then fill the inside of the sock with hot water or steam and allow the resin to cure or harden. The finished product becomes a hard, fiberglass type material that should last for decades.

Pipe bursting method

Pipe Bursting Method

Pipe Bursting

Workers dig a hole next to your home and another hole in the street near the city's sanitary sewer. They attach a device to the new sewer pipe and pull the new pipe out to the road. The device busts out the old sewer line while clearing a path for the new line.

Flood Grouting method

Flood Grouting Method

Flood Grouting - A two step process involving chemicals that are poured through the sewer line and seal any cracks in your lateral.

Slip Lining - Depending upon the size of your existing lateral and local ordinances, in some cases a smaller diameter pipe can be simply pulled through your existing lateral and connected to your home and the sanitary sewer in the street.

Grout Packing - This type of fix uses a machine that is pulled through the existing lateral and pumps grout, a sealer, into any cracks or bad joints along the way.

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