Passive Wastewater Treatment System

NaturalFlow brings you truly passive wastewater treatment systems. For owners, this means long-term treatment options, minimal costs and minimal supervision.

Replicating nature’s biological purification processes, NaturalFlow is a free and eco-friendly way to treat wastewater. As the system utilises vermiculture, it greatly improves an area’s soil structure.

What are passive treatment systems?

Passive water treatment systems do not have an external power source, have no perceptible operation and do not require chemical reagents to conduct treatment.

Passive treatment systems are generally considered for storm water runoff, low pollutant runoff and acid drainage seepage. But with systems like NaturalFlow, passive treatment can be as effective with black water (from toilets and kitchen).

Why use a passive system when there are active systems?

When it comes to rural sewage systems, passive is superior to active. Why? An active system requires energy to elevate, distribute and treat wastewater. In most cases, the energy source is electricity. Active systems also have moving mechanical parts.

For property owners, this means:

  • Higher installation and operation costs
  • More complex maintenance required
  • Higher risk of damaged components

Beyond the advantages of passive systems over active systems, NaturalFlow also provides the following benefits:

  • Quiet biosystem

          With no pumps and aerators, NaturalFlow treats your water without any noise.

  • Eco-sustainable

          Treating water just like nature does, no external energy or harmful chemicals are used.

  • The choice for difficult sites

          Some sites are difficult for other systems but NaturalFlow thrives on them. Whether your site is steep or difficult to access, NaturalFlow can fit and works efficiently.

Truly passive treatment systems

Many companies adopt the term passive treatment, but only a few offer real passive systems – and none are like NaturalFlow.

NaturalFlow offers a sewage and wastewater treatment that operates with zero electricity and has no mechanical operating component. Its system is cleverly designed to lead waters to their appropriate treatment route and purify them enough to be reintroduced to nature.

Our systems do not use reticulating pumps or aerators. Using trickle filtration and vermiculture, NaturalFlow treats wastewater like how the forest floor breaks down solids to fertilising substances. 

Passive, not Inactive

NaturalFlow and septic tanks are both passive systems but NaturalFlow gives one clear advantage. Unlike the septic tank that simply acts a settlement chamber, NaturalFlow treats wastewater. NaturalFlow doesn’t sit and accumulate waste, waiting for future removal. The system continuously treats waste daily.

Contact Us Today

NaturalFlow is the solution for rural domestic and commercial sewage treatment. For more information on our wastewater systems, download our brochure or contact us on 0800 628356. Our friendly team is ready to assist and guide you to the nearest NaturalFlow installer.

Talk To Us Today

Waterflow NZ Ltd has professional Installers and Designers that cover every region of New Zealand, so where ever you are situated from the Cape to the Bluff, just call our friendly team now to find out the closest one to you.


What Others Think

“Gee I love you guys :)”

I was called this morning from Rangi to say the 6-monthly inspection is being done at 2pm today.

Your guy doing it has been held up, so he actually called to let me know.
This is never happens normally with tradie type people.

If your company ever needs someone to sell your systems up this end of the woods then give me an interview.
After my experience with all your people, I would be proud to sell it!

Kim Robson


What Others Think


“NaturalFlow system is such a basic and easy system to look after and operate. We are very pleased with it and are glad we went with the system. The grey water has certainly been great on the gardens and the black water bed once planted looks after itself. Great!”

Dennis & Marie


What Others Think

“Looks after itself”

“Back in 2008 along with our building projects we decided to go for the NaturalFlow sewage system as it didn’t require any power, on our site. We have been very impressed with the performance of this system, with very little maintenance, it basically looks after itself.
Without hesitation I would recommend the NaturalFlow system to anyone as I have had no difficulties with product or the friendly team at Waterflow NZ Ltd. 



What Others Think

“Low site impact”

Just a quick email to say a huge thank to you , ken & the team.
Stoked with the work done , the boys on the diggers did a awesome job .
Every thing was left nice & tidy , super happy !!
Xmas bonus for all !!

John Cullen