Resources and FAQ

Resources – useful guides

Looking After Your Disposal Area

A simple one page guide on how to look after your wastewater disposal area.

Frequently asked questions

What are the methods for disposing of wastewater?

Absorption trenches

A shallow, underground trench that can vary in design, width and length depending on the type of soil and the size of your house. Wastewater flows downhill from the septic tank to the trench. A collection well with a pump can be installed if the trench location is higher than the septic tank.

Evapotranspiration beds

Used when soil conditions are less suitable for absorption trenches and there is limited space. Typically, they are a rectangle area of ground that is excavated up to 600mm deep, filled with gravel and plumbed to disperse the water evenly. The top soil is moulded over the top of the bed and planted with grass and other plants.

Sub surface effluent irrigation

Effluent grade poly pipe buried underground, with evenly spaced drip emitters which allow a pre determined amount of wastewater into the soil across a wide area.

Surface effluent irrigation

Can simply be a line of above ground pipe and sprays.  

BluenGrey can advise on the best method for your particular property and septic system, taking into account any requirements that your Council has and subject to a Geotechnical Report.

Sprinklers do get blocked and it is the responsibility of owners to check between services. They can become blocked due to various factors such as:

  • Dirty water from the clarification chamber
  • Sludge
  • Septic system is overdue for a pump out
  • An aeration problem.

Sprinklers can also stop working because the pipe is kinked or damaged (due to moving them or mowing) and the water can’t get out.

You can tell if the trench has failed because the area will be soggy, smelly and covered with lush vegetation and weeds. Sewer lines may block. Absorption trenches should last for 15–25 years, but if they are not maintained properly the trench life can be reduced to as little as two years. This is why you need to pump out the sludge in the tank every 3-5 years.

There are a few reasons your system may need upgrades to the irrigation:

  • Your irrigation is broken and the wastewater is not able to be dispersed into the disposal area.
  • Not enough sprinklers
  • Sprinklers are in the wrong location (not in the area specified in Geotechnical report or by Council) 
  • Sprinklers are in a low boggy area. 

Generally, your irrigation should remain as specified in your Geotechnical Report.

No, NSW Health and local Councils do not suggest that effluent is used to water fruit or vegetables.

It is a herbicide within the drip emitter that prevents roots blocking the dripper outlets.

Interested in upgrading your absorption trenches, evapotranspiration beds or effluent irrigation?

Get in touch with our friendly and knowledgeable team to organise an on-site inspection today.

BluenGrey Wastewater Irrigation Service Provider in South East NSW


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    “Rod Wilks and the crew at BluenGrey put in a massive water tank for us after our old concrete tank began to leak. We were caught north of the Qld border the whole time but just a phone call was all that was needed for Rod and the team to take care of everything for us during our absence, including design, liaison with manufacturers, site preparation and integrating the new tank with existing lines. We genuinely recommend this business to anyone who wants a super professional and experienced outfit for everything tanks and septics.”

    – Bernie and Deb Morrison, Kianga.

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    “BluenGrey are an absolute pleasure to deal with. Their Service Technicians are always professional and reliable, and I like to know that our wastewater system is looked after so we’re always meeting our Council’s regulations. I feel reassured knowing I can call on them should I have any worries about our system, and especially that they can respond to emergencies.”

    – Emma, Shoalhaven

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    “Having made the decision to move to a semi-rural property at Yass we investigated options for our grey and rain water requirements. We approached BluenGrey who provided a range of options for us to select from. Their personal and professional approach, which included on-site meetings, ultimately led us to choose to proceed with BluenGrey who offered a ‘one stop shop’ service at competitive prices. The installation was trouble free and their follow-on service and advice has been excellent. We are completely satisfied with the BluenGrey services and have no hesitation in recommending them to future customers.”

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    “We would like to thank Rod for all his guidance and patience while we were investigating water and sewerage systems, and asking a myriad of questions. We had never built before and knew nothing about what we needed for water and sewerage, so Rod was a fountain of knowledge. His expertise has been exceptional. Both the water tank and the sewerage system were installed hassle-free and passed Council inspection without any issues. We look forward to an ongoing relationship with Rod when he visits to do the necessary checks and balances of our sewerage system”

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    “From our initial conversations through to final installation BluenGrey were very helpful in every respect, and courteous and obliging with regards to my requirements. Work commenced on time as planned with pictures texted through to us during the installation showing progress. All in all job a well done with zero issues. I would recommend BluenGrey to anyone considering waste disposal units and / or rainwater tanks.”

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