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Sewer Cleanout

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What are sewer cleanouts and why do you need them?

Many things can cause a blockage in your sewer line. Tree roots, damaged or defective pipes, sanitary and personal items, toilet paper, paper hand towels, plastic toilet cleaners, wet wipes, grease, and other foreign objects, to name a few, can make their way into your sewer system causing blockages. Unblocking the drain using a proper drain clearing process is easier, faster, and less stressful for both you and the Plumber if your home has drain or sewer cleanouts.

From our experience about 80% of Sydney homes we visit to clear a blocked drain will have one or more accessible sewer cleanouts somewhere on the property that will be suitable for us to gain access into their sewer line to use our high-pressure water jet and CCTV drain camera inspection equipment to clear the blocked drain they are experiencing.

What is a sewer cleanout?

Cleanouts provide Plumbers with direct clearing and inspection access to your underground sewer line in the event you have a sewer blockage. If you have one or more cleanouts they are normally located outside of your home in the front or back yard or can be at the side of the house outside a bathroom, kitchen, or laundry. Cleanouts typically go unnoticed until there is a problem. It is important not to confuse a “Gully” with a Cleanout as not all Gully types are suitable for drain clearing and inspection purposes.

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Having proper access to your underground sewer pipes is the most important consideration for a Plumber dealing with a blocked drain

How to tell the difference between a cleanout and a gully

Identifying a cleanout (CO)

A Cleanout (CO) provides Plumbers unhindered access via a direct access shaft to the sewer line underground. Depending on the design and location of the Cleanout, the shaft will provide access to either one, two or three directions within the sewer line - upstream, downstream, branch drain. Unlike a Gully which has a loose plastic or metal grate on top, Cleanouts will always have a sealed plastic or metal lid secured by either screws, bolts, or a screw on or bayonet cap. As Cleanouts are a direct access point to the sewer line, they must be sealed to stop sewer gases from escaping into the environment.  

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Identifying a gully (ORG)

A Gully or ORG (Overflow Relief Gully) has only one purpose. To provide an overflow point in the event of a Sydney Water main line sewer blockage, so sewage does not backup inside the house. Unlike a Cleanout which has a sealed lid or screw on cap, Gullies will always have a loose plastic or metal grate on top. The grate will float off during overflow events allowing free flow of wastewater onto the ground outside the house preventing flooding inside the house. Gullies do not need to be sealed because they have a 'P' trap water seal at the bottom of the shaft which prevents sewer gases from escaping into the environment.

sewer gully trap blocked drain sydney nsw

Gullies come in many different designs, shapes, and sizes. If you want more information about gullies? Just Google "what is a sewer gully" or "what is an ORG" for more information or you can call us. 

Examples of suitable cleanouts used to clear and inspect blocked sewer lines

The word "Cleanout" is a generic term used to describe any above ground level direct access point to the sewer line underground. An overflow relief gully (ORG), floor waste or fixture trap, disconnector gully, plumbing fixture outlet, vent, or underground inspection opening (IO) is not a sewer Cleanout.

Cleanouts come in many different designs, shapes and sizes and are designed specifically for sewer and drain clearing and pipe inspection purposes and the use of drain clearing equipment and tools such as high-pressure water jets, electric eels, and CCTV drain cameras.

Watch this drain clearing video to see us working through a sewer cleanout. 

Suitable Cleanouts
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PVC Bolted Trap Screw

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Cast Iron Bayonet Lid

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PVC Stack Gate 

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PVC Inspection Point

Not all homes have cleanouts

Not all cleanouts are suitable

Not all cleanouts are accessible

But what if I don't have a cleanout?

No Cleanout

If you do not have drain Cleanouts (CO), sewer blockages can still be cleared but it can sometimes be more challenging and time consuming. Once it has been established that suitable cleanout access is not available the Plumber will need to gain access to the underground sewer line by other means such as excavating down to the sewer line to access an Inspection Opening (IO) or to cut into the existing pipework to create an access point, dismantling or cutting into vents or removing internal fixtures such as toilets, basins or laundry tubs, however, clearing blocked sewer lines from inside the house or by removing plumbing fixtures should always be considered a last resort!

Why would a cleanout not be suitable?

Cleanout Not Suitable

There are no two sewer systems the same. A sewer system is an underground network of pipes running under your home (Internal Branch Drains) that connect plumbing fixtures (toilets, basins, showers, sinks, tubs, baths) inside your house via junctions to an underground network of pipes running around the outside of the building (External Main Drain) that leads to your connection with the Sydney Water Sewer Main Line. A cleanout installed on a branch drain will only give access to that branch drain and possibly a section of the main drain but not to the entire sewer network and cleanouts installed on the main drain usually only give access to the main drain and not the branch drains.


As sewer systems are unique to each property there are infinite variations to the above however sometimes although there may be existing cleanouts available on the property the blockage can be located anywhere within the homeowner's sewer network that is not serviced by those existing cleanouts. If this turns out to be the case, then other work will need to be carried out or another cleanout installed to gain access to that affected part of the sewer line.

Sewer Diagram Bathroom Example

Your sewer drainage system consists of three sections.

  • Fixture Pipes - A Fixture Pipe (40mm - 50mm) connects a single Plumbing Fixture inside your home to its Branch Drain under the floor underground. Fixture Pipes are above ground inside your house and are usually PVC pipes. If you look under your Basin, Kitchen Sink or Laundry Tub you will see that Plumbing Fixtures "Fixture Pipe".

  • Branch Drains - Every Plumbing Fixture in your home also has a dedicated Branch Drain (100mm) under the floor underground that carries the waste from a single Plumbing Fixture to the Main Drain outside the house. Your Fixture Pipes are connected to your Branch Drains and your Branch Drains are connected to your Main Drain. Your Branch Drains can be earthenware or PVC pipes. You will have multiple Branch Drains and they are usually found under your home underground, and they are called "Internal Drainage".

  • Main Drain - This is a single sewer line (100mm - 150mm) underground that runs from your house down to the point of connection with the Sydney Water Sewer Main Line. Your Main Drain carries waste from all the Plumbing Fixtures, Fixture Pipes and Branch Drains inside your home down to the Sydney Water Sewer Main Line. Your Main Drain can be earthenware or PVC pipes and are usually found underground outside of your house. We call this part of your sewer system "External Drainage".


1 - Sydney Water Sewer Main Line (Owned by Sydney Water)

2 - Sydney Water Manhole Access Chamber

3 - Point of connection with Sydney Water Sewer Main Line

4 - Main Drain (External Drainage located outside of house)

5 - Branch Drains (Internal Drainage located under house)

6 - Main Drain Inspection Opening (IO) (Underground)

7 - Branch Drain Inspection Opening (IO) (Underground)

8 - Main Inspection Shaft (IS) (Required on all sewer lines)

9 - Sewer Cleanout (CO) (Not all homes have Cleanouts)

10A - Toilet Pan - Direct connection to Branch Drain

10B - Basin - Fixture Pipe connection to Branch Drain

10C - Bath - Direct charging connection to Floor Waste P Trap

11A - Overflow Relief Gully (ORG) P Trap (For sewage overflows)

11B - Shower - Direct connection to Branch Drain via P Trap

11C - Floor Waste - Direct connection to Branch Drain via P Trap

12 - Stack Branch - Servicing 2nd floor Plumbing Fixtures

13 - Pipe length - Before 1980 - 600mm | After 1980 - 1200mm

14 - Pipe length house to main line - 5 metres to 100 metres

15 - Vent line - Servicing vent pipe to above roof

16 - Sewer line upstream servicing kitchen, laundry & ensuite

I can't find any cleanouts?

Can't Find Cleanout

Many homes can have one or more cleanouts but unfortunately, they can be difficult to find. Sewer cleanouts need to be installed in such a way as to be exposed at or above ground level and always kept clear so they can be found by the homeowner or a Plumber when they are needed however over time existing cleanouts can become concealed or hidden in one way or another.

  • Buried by landscaping works

  • Concealed under hot water heaters and air conditioner units

  • Covered over by concrete paths, driveways, paved areas, or wooden decks

  • Built over by garden sheds, retaining walls, tennis courts, swimming pools or home extensions

  • Hidden in garden beds under leaves, dirt, plants, hedges, trees or simply covered by grass or a pot plant

The best way to find sewer cleanouts on your property is to follow the path of the sewer line using your Sewer Service Diagram (SSD). An SSD is a plan or map of your sewer system. All properties have a Sewer Service Diagram, if you don't have one you can get one online from Sydney Water or we can get one for you. Having your homes Sewer Service Diagram available when your Plumber arrives to unblock your drain is always a good thing, it will save time and frustration for everyone involved and the Plumber will thank you for that!

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Cast iron cleanout hidden in the garden under a shrub and leaves and covered by a sandstone rock.

Homeowner has lived in the property for 25 years and had no idea this cleanout existed!

Examples Of PVC Cleanout Installation

Cleanout Installation

When sewer blockages are located in a part of the drainage system that cannot be accessed via existing ground level Cleanouts Plumbers may have to excavate down to the sewer pipe to expose an Inspection Opening (IO) to gain access into the pipe to clear the blocked drain. Once the blockage has been cleared one option is to simply reseal the Inspection Opening and backfill the excavation however any future blockages in the same section of drain will require another excavation in the same location to access the same Inspection Opening again. This is true particularly in the case of recurring tree root blockages. As the drain has already been excavated in the first instance to gain access to the Inspection Opening it is always a good idea to install a Cleanout in this location so any future blockages can be cleared quickly without having to excavate again. This saves time and money for the homeowner on any future callouts for blocked drains or for regular servicing to remove recurring tree root regrowth.  

sewer cleanout installation

Single Cleanout Installed On PVC Sewer Line

double sewer cleanout

Double Cleanout Installed On Earthenware Sewer Line

drain cleanout

Single Cleanout Installed On Earthenware Stormwater Line

What Is An Inspection Opening (IO)?

Inspection Opening (IO)

If no Cleanouts (CO) can be found your Sewer Service Diagram (SSD) will also show where the sewer Inspection Openings (IO) are located. Sewer Inspection Openings are sealed earthenware or PVC access points on the sewer line underground that are also used for drain clearing and inspection purposes however Inspection Openings are not accessible at ground level like Cleanouts, they are located directly on top of the sewer pipe underground so they will need to be excavated and exposed to gain access into the sewer line. All homes will have several sewer Inspection Openings as Australian Standards AS/NZS 3500 requires Inspection Openings to be installed in specific locations on all sewer lines. Older earthenware Inspection Openings installed up until the late 1970's when earthenware pipe joints were sealed with cement will consist of an oval shaped earthenware cap with a cement seal on top, while more recent earthenware Inspection Openings installed when rubber ring seals were introduced consist of a round earthenware plug with a black rubber ring seal held in place with a metal clip exactly like in the example below, and PVC Inspection Openings simply have a threaded PVC screw on cap.

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1. Excavation to expose sewer inspection opening to access drains under bathroom 

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2. Inspection opening exposed with cap, rubber ring seal and metal clip in place

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3. Inspection opening exposed with cap, rubber ring seal and metal clip removed

To recap: A Cleanout (CO) is a ground level access point giving quick and easy access to the sewer line and an Inspection Opening (IO) is a buried access point on the sewer line that will need to be excavated to access.

Need more information on sewer cleanouts? Just Google, "what is a sewer cleanout?"

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