Sanitary Sewer

A sanitary sewer is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment facilities or disposal. Sanitary sewers are part of an overall system called a sewage system or sewerage.

Where does it go?

Did you ever wonder what happens when you flush your toilet or pour something down the drain? Whenever wastewater leaves your home, it doesn’t just “go away.” When you flush the toilet, take a shower, wash dishes, or do laundry, the wastewater needs to be cleaned before it can be returned to the environment. When wastewater goes down the drain in your home, it travels through the sewer system to a treatment plant.

What is the difference between sanitary sewer and stormwater sewer lines?

A sanitary sewer pipe is located mainly in the street or another easement (side or rear property line) that is designed to transport wastewater from sanitary fixtures inside your house or place of business to the wastewater treatment plant. Sanitary fixtures include sinks, bathtubs, showers, and washing machines. A storm sewer pipe is designed to carry rainwater away. Storm sewer lines are normally much larger than sanitary sewer lines because they are designed to carry much larger amounts of water. Primarily, open drainage ditches perform this function in most neighborhoods.

What part of the sewer system serving my property is my responsibility to maintain? What is the Township’s responsibility?

The Township is responsible for maintaining its main sewer lines. Private property owners are responsible for the sewer service line. This line starts at the tap on the sewer main, extends across the customer’s property, and connects at the home or business.

What preventative maintenance measures does the Township of Woodbridge take to keep sewer lines flowing properly?

The Township of Woodbridge uses the following methods to clean and maintain sanitary sewer main lines:

1. Trouble areas, neighborhoods served by typically older sewer mains blocked by tree roots, are kept on a routine maintenance schedule.

2. Sewer main lines are washed out routinely or as trouble calls are reported.

3. The Township can conduct sewer smoke or dye tests to identify main line cracks that can cause sewer leaks.

4. The Township can run a small television camera down the sewer pipe to identify main line cracks and deterioration.

5. Based on any testing that is conducted, the Township will prioritize replacement and/or rehabilitation of sewer mains.

What should I do if a sewer backup occurs at my home or business?

CALL US FIRST! at 732-738-1311. Even if you suspect that the problem may be on your service line, it’s best to call the Township first before you call a plumber. Our service crew will check the Township’s main lines to either identify and repair the problem or to determine whether or not you need to call a plumber. (The Township will wash the sewer main line regardless of where the problem exists.) This step could save you an unnecessary plumber’s bill!

What can I do to prevent a sanitary sewer back up in my home or on main lines?

Here are some very important rules to follow to help keep sewer lines flowing:

1. NEVER pour grease down drains or into garbage disposals. The grease will turn into a hard solid that blocks lines and can result in a sewer back up. Let grease cool down and dispose of it in the trash.

2. Putting food down a garbage disposal in your kitchen sink can be a convenient method of throwing away leftovers. However, many foods, such as certain vegetables and vegetable skins, have natural oils in them. These food particles can convert into grease in your pipes and sewer service line. Frequent use of a garbage disposal can contribute to blockages in service and main lines.

3. Roots from trees can grow into sewer line joints and obstruct flow. If the Township determines that a customer’s service line is blocked by root growth, they must contact a licensed plumber to have the line cleaned from the house to the sewer main. If there are several mature trees and bushes in your yard located near or around where your service line runs, you may want to periodically have the sanitary sewer service line checked and/or cleaned out by a plumber, especially if your toilets, sinks, etc. are experiencing frequent blockages or backups.

4. BE ON THE LOOKOUT! If you see an overflowing manhole, detect a sewer odor, or observe evidence of sewage on the ground or in a stream, please report this by calling 732-738-1311. With your help, we can keep the lines flowing.

SEWER RIGHT OF WAY: Buildings, Landscaping, Fencing, and other Property Improvements

The Township is assigned certain rights to legally gain access to our publicly-owned utility lines that run near or through your property. These rights are known as easements or right-of-ways, and they allow the City to gain access to and perform necessary maintenance on utility lines. Before building structures, performing landscaping, or installing a fence, you should check the legal survey plat of your property to identify where these easements are located. If you do not have a copy of this plat, you may contact the Township to inquire if any sewer or other Township-owned utility right-of-way exists on your property. Should an easement exist, the Township can determine whether or not a structure, landscaping or otherwise, can be located in or around this easement.


Generally, sewer backups occur during rainstorms because the sewer is too overloaded to take the flow. This extraneous flow is expensive because treatment facilities are not designed to handle this type of overload. Both the Middlesex County Sewer Authority and the Rahway Valley Sewer Authority are requesting that Woodbridge Township take measures to eliminate this problem. This costly excess is primarily caused by stormwater that infiltrates the sanitary sewer through illegal connections. Despite our many efforts, there are still some homes in the community that have illegal drainage into the wastewater collection system. With this in mind, we have prepared the following list, descriptions, and remedies that will assist homeowners in eliminating these problems before inspection in order to obtain a Certificate of Approval from the township. Sanitary sewer problems are generally caused by few reasons. All are able to be cured.

Prohibited Discharges into the Sanitary Sewers:
1. Roof drains (gutters, leaders, downspouts)
2. Floor drains (basement, foundation)
3. Sump pumps
4. Yard and driveways drains
5. Sanitary sewer trap caps (missing, loose, cracked, holes)

Roof Drains

No stormwater discharge from downspouts may be connected to the sanitary sewer system. If a house has a connection of this type, it must be plugged permanently. The aboveground downspout must be disconnected from the existing belowground drain that leads into the sanitary sewer system. The underlying drain must then be plugged with newspaper and the bell housing filled with concrete. It is now important to redirect the water away from the foundation. This can be done using a splashblock or by connecting the downspout to a PVC pipe that redirects the stormwater flow from the house to the street.

Floor Drains

No home in the township is permitted to have cellar floor drains. Use a good, tight plug that either you or your plumber can install for a few dollars. Install it a few inches below the floor and cover it with concrete. Remember that sewer gas can be lethal. A floor drain that permits drainage to flow to the sanitary sewer is an opening that can let sanitary sewage or toxic gas back into your cellar.

Sump Pumps

A sump pump is a device that pumps stormwater that has accumulated in, around, or below the foundation. This water should discharge out to the street. A length of plastic PVC pipe or rubber hose will readily carry the water to the street. It should never be discharged to a sink or any other opening into the sanitary sewer. If the home is not equipped with a sump pump and the homeowner desires to install one, the pump can be placed in either a sump pit or a depression at the sanitary sewer trap. In a few instances, it may be necessary to make a hole in the cellar floor to accommodate the pump.

Clear water from fountain drains, cistern overflow, roof drains, and similar sources should not be connected to sanitary sewers because it tends to hydraulically overload the collection system and wastewater treatment plant.

Yard and Driveway Drains

Under no circumstances should this water be discharged to the sanitary sewer. Yard or driveway drains should discharge out to the street. This can be easily done by installing an approved underground piping system that leads to the curb. Any opening that permits drainage to flow to the sanitary sewer should be closed permanently with a good, tight plug and sealed with concrete.

Trap Caps

Sanitary sewer trap caps should not be missing or defective. If they have holes, cracks, and/or do not screw tight, replace them with new ones. These openings are not permitted to drain your cellar.

These requirements will help reduce sewer backups, eliminate illegal connections, decrease the volume of stormwater entering the system, and lower the cost of treatment to the users.

Sanitary Sewer Literature