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Drainage and Blockages

Maintain your house drainage system (including sewerage)

Your home is connected to Council's sewerage system by a pipe called a house drain. The house drain belongs to the home owner.

A Vertical Inspection Shaft (VIS) is located where the house drain meets Council's sewerage system. It is located within the property and has a small concrete surround with a water-tight cover. The VIS also belongs to the property owner. Removal of this cover enables a plumber to locate and identify a blockage or problem at the connection of your property or in Council's sewerage system.

Standard 100mm Bolted Trap Screw fitting used to seal the Vertical Inspection Shaft at the point of connection to sewer
Photo: Standard 100mm Bolted Trap Screw fitting used to seal the Vertical Inspection Shaft at the point of connection to sewer

Manhole, Vertical Inspection shaft with 150mm bolted trap screw fitting and overflow relief gully with hose tap over
Photo: Typical household-type overflow relief gully with hose tap

All houses should have an overflow relief gully (ORG) - also known as an overflow gully or gully trap. The ORG is designed to overflow if a blockage occurs and preventing flooding inside the house. It is a dished concrete surround with a loose-fitting grate. The ORG must be lower than all floor waste outlets within the home, and finished 75mm above ground level. The loose-fitting grate should never be sealed or restrained by placing pot plants or other materials on top of it.

The ORG is an opening that acts as a relief point between the house drain and Council's sewer system, and prevents smells and overflows entering buildings. All wastewater from the laundry, kitchen, bath and shower goes through pipes into the ORG. The toilet is different as it connects separately to the main house pipe.

The ORG is located outside your house, generally in the area outside your kitchen. The ORG should be above ground level to ensure that stormwater does not enter. Inflow through the ORG is normally unintentional, where stormwater cannot flow away due to landscaping or other obstructions blocking the flow-path of the stormwater. Stormwater builds up around the ORG and then, when high enough, enters the sewer network. Property owners should ensure that no rainwater or run-off water enters the ORG as this will overload the sewer system - and is an offence under the Local Government Act.

If you require a copy of your internal house drainage plan, complete the Application and fee payment here.

What can't I flush down the sink?

Fats and oils clog more than your arteries...

What you put down your sink and into the sewerage system can have a significant impact on the effectiveness of the sewage treatment process and the health of our local environment. You can help protect the environment by disposing of your household waste products thoughtfully.

Fats and oils solidify in drainage pipes forming a thick greasy film and odour. Pouring fats, cooking oils and food scraps down the sink can result in damage to the pipes within your property and cause blockages that can be costly to remove. Small brand label stickers on fruit and vegetables are non-biodegradable and get caught in the sewerage screens that filter waste.

Blockages also cause Council's expensive sewerage infrastructure to perform poorly, or fail. The effectiveness of the treatment process at our sewage facilities is crucial to the health of our creeks, rivers and oceans.

What can't I flush down the toilet?

  • Baby wipes, kitchen wipes, nappies, sanitary items, cotton tips - Flushing cotton tips/buds and baby wipes down the toilet can cause significant sewer blockages along the network and equipment failure at sewage treatment plants by jamming pumping equipment. These should be wrapped and disposed of in the RED bin. Even if baby wipes are labelled 'flushable' they can still cause major problems.

  • Paints, pesticides and other hazardous materials - Hazardous chemicals used around the home and garden, including paints and pesticides, can corrode your pipes and damage the environment.

  • Pharmaceuticals, syringes - Never flush syringes, razor blades, chemist (or other non-biodegradable) products down the toilet or sink. Pharmaceuticals, medicines and syringes should be taken to your chemist for safe and free disposal, not disposed of in your RED bin.

A ' Think Beyond the Sink and To Flush or Not to Flush424KB pdf(PDF, 424KB)' information sheet is attached.

Sewer infiltration and overflows

Port Macquarie-Hastings Council's sewerage system is designed to transfer sewage and wastewater from each home or business to the wastewater (sewerage) treatment plants via house drains, sewers and pumping stations. The sewerage system is not designed to carry runoff from rainfall which can result in overflowing into other residential households or businesses. In times of heavy rainfall, the sewerage system can become affected by the inflow of stormwater which, in turn, can have the following effect:

  • The capacity of the sewer network becomes overloaded; and
  • Sewage overflows can occur.

The majority of inflow is caused by:

  • Illegal rainwater connection into the sewer network; and/or
  • Landscaping that diverts stormwater into manholes or overflow relief gullies.

Residents need to be aware that any discharge of stormwater into the sewer network, whether through the overflow relief gully or connection of stormwater downpipes, is illegal and can result in a Council fine.

What constitutes inflow/infiltration, and why is it a problem?

Inflow/infiltration is any external source of water, stormwater or groundwater that enters the sewerage system.

Inflow/infiltration increases the volume of water in the sewer systems which can result in the capacity of the network being exceeded. This causes the network to overflow, resulting in environmental harm and creating risks to human health. To fix this problem through the construction of larger pipes, pump stations and treatment plants would cost Council many millions of dollars - which is not an acceptable outcome for ratepayers.

What do I need to do?

Owners/occupants might not always be aware that rainwater from their property is entering the sewerage system. Previous residents might have connected rainwater pipes illegally to the network. Owners/occupiers must investigate their drainage system by:

  • Checking that all downpipes discharge to the ground or to the street. This can be done by discharging water into your downpipe and seeing the point where the water flows out. If no point of discharge can be found, there might be an illegal connection; and
  • Inspect the area around the overflow gully to ensure that stormwater can flow away. Verify this during a rain event and if water dams up around the overflow gully, adjust the landscaping or remove the obstacle.

Please contact Council if you cannot find your overflow gully or think you might have an illegal connection. Contact Council’s Customer Service Centre on (02) 6581 8111 or email council@pmhc.nsw.gov.au.

Protect the manhole

Standard twin lift manhole lid and surround (nominal sizes:- Lid 720mm Diameter and Surround 900mm Diameter)
Photo: Standard twin lift manhole lid and surround (nominal sizes:- Lid 720mm Diameter and Surround 1200mm Diameter)

A manhole will be at ground level with a circular concrete cover, approx. 1200mm in diameter (see photo).  The purpose of the manhole is to allow access to Council’s sewer pipes. 

If you have a manhole on your property please ensure it is not obstructed, and has a 1 metre clearance around it to allow easy access for inspections or maintenance.  Council continues to experience problems with buried, covered or retaining walls around manholes.  Manholes are installed for maintenance and inspection purposes and must not be covered, altered or have reduced access in order to allow safe entry for CCTV camera, sewer choke (blockage) clearing and in some instances, where necessary, Council staff.  Please be aware that it is an offence under the Local Government Act to build anything over the manhole or cover it with soil or grass.

If you wish to change the ground level around the manhole on your property, please contact Council’s Customer Service Centre on (02) 6581 8111 or email council@pmhc.nsw.gov.au to arrange an inspection.


Sewer Operations staff preparing to enter a manhole with required fall arrestor and tripod setup - hence requirement for 1 metre clearance.


This page was last updated on: 19 June 2020