Power-Free Grey Water Treatment Systems

NaturalFlow is an innovative way to treat grey water in homes and commercial properties, making the process significantly simpler, cost-effective and 100% sustainable.

grey water treatment system

Revolutionary Sewage Treatment

After following the history of sewage treatment, NaturalFlow recognised the benefits of treating low-volume, high-toxicity black water separately from the high-volume, low-toxicity grey water. NaturalFlow created grey water treatment systems that separate these waters at their source, they then receive selective treatment within the system, resulting in a number of advantages.

What is Grey Water?

Grey water comes from baths, showers, basins, laundries etc. By having a grey water system, homeowners and business owners can convert waste into a valuable resource. Throughout New Zealand, many are already enjoying the benefits of reusing grey water. Some use grey water to water their lawns while some reuse the water for other non-potable applications. As grey water has less solid waste than water coming from toilets and kitchens (black water), it is easier to treat and safe to reuse as irrigation for landscaping, orchards, lawn and other non-potable uses.

How NaturalFlow’s Grey Water Treatment Systems Work

In other sewage systems, like septic tanks, grey water and black water are piped together into one big tank, where the solids, over time, settle to the bottom and the lighter scum floats to the top, leaving the relatively liquid water in the middle. As the solids and scum accumulate and build up, the water becomes narrower, and in effect, more solids are released through the tank, out into the soakage fields. The same thing happens when there is an influx of wastewater into the tank, and there is no time for the solids to separate and settle. The result: the trouble and foul odour that septic tanks are known for.

With NaturalFlow’s grey water treatment systems, process is better controlled.

Grey water and black water are separated at their source for selective treatment within the system. This prevents the low-toxicity grey water from emulsifying with the high-toxicity black water, simplifying the treatment process.

The black water passes into the Wormorator, an enclosed ecosystem simulating the forest floor, where the solids are separated from the liquid and treated through vermiculture, filter media and other natural processes.

Separately, the grey water undergoes a series of natural settling and filtration systems that reduce scum and solids. The water is later combined with black water for final disposal into the soil and the environment.

Grey water has low solids but carries soap scum. If this scum is retained for too long, it begins to putrefy, as it loses oxygen and allows anaerobic bacteria to grow. Thus, the sooner this water is released into the environment, the safer it is.

The Do’s and Don’ts with Grey Water

What to Do with Grey Water

    • Use Immediately

Grey water should be reused right after it is treated when toxins and scum are at their lowest levels.

    • Garden and Land Irrigation

The treatment process reduces the scum and solids which makes the water usable for surface or sub-surface irrigation systems.


What Not to Do with Grey Water

    • Non-Potable

No matter how stringent the treatment process is, grey water is still waste water. It is not safe for consumption and should only be used for reintroduction to the environment.

    • Stagnation

Allowing grey water to store for too long, without aeration, will cause it to stagnate which will create toxins that are harmful to humans and nature.

    • Water Reintegration

Grey water use should not be reintroduced to bodies of water because its chemical residue is harmful to these types of water.

    • Toilet Flushing

Only with further treatment Grey water can be reintroduced to the plumbing system to be used as an eco-friendly substitute for flushing toilets.

The Benefits of NaturalFlow

By its power-free, sustainable practice, NaturalFlow brings a wide array of benefits:


Low Maintenance

The NaturalFlow System comes with easy and straightforward installation process operation and has extremely low maintenance requirements. You can be trained to manage your system, which mainly involves easy visual checks on the system. Having high resistance to shock and intermittent loading, NaturalFlow’s components are highly robust and require minimal maintenance.

By choosing NaturalFlow, many homes and businesses across New Zealand have enjoyed significant savings from reduced maintenance activities. Compared to other wastewater systems, NaturalFlow needs 75% less maintenance work.



When it comes to eco septic tank systems, NaturalFlow is a cut above the rest. It uses natural processes to treat grey water and black water. It does not draw from any other source of power or other resources in any of its black and grey water treatment systems. It is self-sufficient, powerful and built to work at peak performance from day one and into the future.

Using a natural filtration process to convert solid waste into a liquid fertiliser, NaturalFlow dramatically reduces the impact of wastewater on the environment.

Contact Us Today

If you want to learn more about the NaturalFlow grey water treatment process, contact our friendly team. You may also call 0800 628356 to find the installer nearest you.


Suitable for Residential and Commercial Use

The NaturalFlow grey water system is suitable for both homes and businesses. Our range of systems can accommodate 1-2 bedroom houses or facilities with 10 staff members up to 3-8 bedroom houses or businesses with 40 employees. Running without pumps and aerators, the system works quietly to minimise disruption to your business’ operations or the tranquillity of your home. With NaturalFlow’s design, it fits well in steep and difficult sites benefitting homes and businesses in challenging locations.

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