A Flushing Composting Toilet


A Flushing Composting Toilet

Making a flushing composting toilet for David's Mud Cubby 

“It was the right choice given all the moving parts of this decision. It’s like the composting toilet that no one needs to know is a composting toilet”


David M.




December 2021

David started building his Mud Cubby around the lockdowns as a form of creative outlet as well as avoiding a commercially made granny flat. The Mud Cubby is an off-grid, handmade, expression of David’s hard work version of a granny flat. The structure is independent of the main house and provides a peaceful sanctuary that friends and family can enjoy. David has told us that many friends have relished their time spent in the Cubby, and they have even had offers to pay full-time rent to live there.

David is no stranger to hard work and building with his business Mud Fun, which has orchestrated projects from clay ovens to cubbies all around Australia.


When it came time to discuss toilets and wastewater options, David got in touch with our Sales Team for advice. The Mud Cubby is an on-ground structure, which means that there was no space underneath the floor for a waterless composting toilet. 

Initially, our recommendation was for one of our Self-contained Composting Toilets - but this didn’t suit the capacity or flexibility that David was looking for. Because the Mud Cubby was going to be used by friends and family regularly the toilet needed to be foolproof and future-proof. 

So we started looking into the SeaLand Microflush Pedestal and what systems were compatible as well as suitable for David's site. This is our pedestal that most resembles a flushing toilet, while still saving a substantial amount of water in comparison to a traditional toilet and septic system. Using this Microflush pedestal meant that David was able to move the waste horizontally to reach a composting tank. 

Normally, the Microflush pedestal is sold with the Sun-Mar™ Centrex 3000 but this system needs to be sheltered from the elements which wasn’t going to suit David’s Cubby. So the tougher solution was to pair the Microflush system with the Clivus Multrum™ CM8 Next Gen. See the below table to summarise the pros and cons of each composting system, specifically about the Microflush: 

Sun-Mar™ Centrex 3000

Clivus Multrum™ CM8 Next Gen





  • Certified/Approved with a Microflush system
  • Higher level of maintenance considering the regular rotation of internal drum
  • System should be placed undercover and out of the weather
  • UV stabilised LDPE can be placed outside and partially buried
  • Design of the tank is capable of draining excessive amount of liquid
  • Larger capacity
  • No current installation manual including the Microflush
  • Not certified/approved with a Microflush

The largest hurdle for David was the space required for the tank. It required an excavation beside the Mud Cubby so that the tank was going to be below the Microflush pedestal. 

The slope of the Microflush system requires a 4% slope; which is a fall of 40mm per metre of waste pipe. We also had to consider the height of the CM8, which is 1300mm. The land sloped away from the Mud Cubby which worked in our favour. So David calculated that he could fit the CM8 behind the Mud Cubby, tucked into the slope by excavating enough space so the CM8 could be on level ground.

What David didn’t expect was that this excavation process was going to require a jackhammer to remove the rocks that were deeper down. This was the greatest challenge to overcome, even creating a moment of doubt:

“I had to dig a lot. I’m glad we have it now but if I had known how much excavation I was going to have to do to get it in I probably would have made another decision. But, I’m glad of my ignorance because now that it’s in place it was definitely the best decision”


Here at Ecoflo, we are just the manufacturer and supplier so our hands are somewhat tied when it comes to installation. We always recommend our customers find a local licensed professional (bonus points are awarded for experience in off-grid systems). Whether it’s to install a toilet or sign off for council applications. 

It was time to call in the cavalry: a local licensed plumber. With the tank in place, the installation of the Microflush toilet just needed to follow the planned slope and lead into the composting tank which was completed under the leadership of said plumber. 

The water is sourced from a repurposed water tank, this type of Microflush system will work with a gravity feed hose or if space doesn’t permit, a water pump to compensate. Our boys did need to install a pump to move the water, and then David took the toilet seat one step further by adding a bidet toilet seat for that luxury experience.

Everyone thus far has loved David’s Cubby and the composting toilet. There were a couple of initial hesitations, but once they were introduced to the toilet it didn’t feel too different from a traditional flushing toilet they were able to embrace the serenity of the Mud Cubby. 

It was challenging but worth it.


In the spirit of reconciliation, Ecoflo Wastewater Management acknowledges the Traditional Custodians of this Country. We pay our respects to their Elders past and present and extend that respect to all Aboriginal and Torres Strait Islander peoples today. 




Ecoflo was the first company in Australia to sell composting toilets certified to the rigorous quality testing of Australian Standards. If you want to be certain your composting toilet has adequate capacity and is safe, you need a waterless composting toilet certified to the tough performance criteria of AS/NZS 1546.2:2008.

Shop our range of certified toilets here