Septic Tanks

Failing Septic Tank?

Our team of professionals can assess your system and suggest remedial action.

Wastewater treatment systems are our passion. And finding the right treatment system for your wastewater or sewage is what we do best.

Septic tanks on their own aren’t commonly used, due to a lack of treatment and environmental concerns of the industry and regulators. Instead, there is a push towards more advanced treatment systems.

That doesn’t mean they are disappearing anytime soon. There are still a handful of applications where a conventional septic tank is permitted and may be suitable, such as large properties with free draining soils and no water bodies nearby.

We install septic tanks, but before you look at this option for your site there are two things to consider: price and the contaminants.

Are Septic Tanks Actually Cheaper? It’s often thought that septic tanks are the cheaper way to go, compared to treatment systems. Not necessarily.

In our experience, septic tanks offer little price benefit when it comes to installation. They are predominantly concrete so require good access and a Hiab to position them. Plastic tanks are available for more difficult sites, but they do come at a higher price.

Due to the distinct ‘septic’ odour and low levels of treatment a much more robust land application system must be considered. Effluent should be discharged into the ground via a soakage bed system - these require excavation and more material so do increase the cost of installation.

Do Septic Tanks Actually Treat Wastewater? The principle of a septic tank is this: the wastewater all enters a tank of one or more chambers, in each chamber the solids settle to the bottom and the scum floats to the top. The clear water in the middle then passes to the next chamber and finally out to a soakage area.

Anaerobic bacteria inside the tank break down solid matter at a very slow rate, therefore the solids accumulate in the bottom of the tank and require periodic removal (suck outs).

The discharged water has no large solid matter but can contain various contaminants; the final treatment occurs in the soil where the effluent is discharged. While the settling process and anaerobic organisms provide Primary Treatment, the wastewater is not cleaned nearly as thoroughly as it would be using a vermifiltration or aeration system.

Common Problems

Many old septic tanks are starting to fail, or no longer meet the current standards.

Blocked Soakage Field Some old septic tanks have no outlet filter, allowing solid material to exit the tanks and enter the land application system. This leads to blockages and results in backed up drains and sewerage overflowing onto your property.

Most old septic systems rely on a trickle discharge, essentially what goes in comes out. Since the land application system is only receiving a small amount of water at a time, it tends to soak away at the beginning of the soakage area; until the constant flow causes a build-up of slime and sludge and blocks the soil, then it progresses along a bit further; this is called ‘creeping failure’. Over a number of years, the entire area will block up.

We can reinstate your land application system to its original state, as long as we know where it is and how big. If the area or location changes significantly, a building consent will be required, otherwise it can be done as repair work. We will dig it up and use new materials to reinstate it.

In many cases, the most future proof option is to bring the land application up to standard and get it approved by council, as this will improve the current operation and future sale value of your property. By doing this we can also add a dosing module to the septic system, improving the loading of the soakage and increasing its life span.

No Septic Access Hatch We can improve access to the tank by adding a riser and lid to an existing septic tank.

To meet current regulations, every septic should have an access maintenance hole. Many old septic tanks had a concrete hatch buried under the ground; which meant that when a suck out was being carried out the hatch would have to be dug up to fully suck out the tank.

Ground Water Backflow Most old septic tanks rely on a trickle discharge, which can cause complications.

If there is high ground water, it can flow back through from the soakage into the septic. This typically occurs on flat sites where the water can’t get away easily. In this situation, large rain events can prevent the septic discharging correctly, in the worst case resulting in sewage overflowing out of the tank onto your property, which is definitely not what you want to happen.

This can be remedied by adding a dose tank to the end of the septic and pumping it into the soakage area. The pump forces the water into the soakage area, where it is unable to return to the tank.

We also have smaller gravity dosing modules to improve the dosing of soakage areas.

Broken Inlet/Outlet Smelly on the Inside and Out

Broken inlet pipes can result in sewage landing on the top of the effluent in the tank. This breaks up the crust, turning your tank into a smelly soup. Simply replacing the inlet junction can stop the smelly problems you are experiencing.

Broken outlet pipes mean there will be no outlet filtration, leading to blockage in the soakage field. Blockage in the soakage results in break out and smelly wet areas on your property.

"We are happy with the installation of our septic system thanks.

The speed from us saying that we were ready for the installation and the job being completed was great. Also the site being left in a nice clean state was exceptional.

Great people all round to deal with. Thank you"

Meghan and Keith - Kaipara October 2020


We’re in 6,000+ backyards around Aotearoa New Zealand

At WaterFlow we work across the country recommending and installing smarter wastewater and sewage systems, for a cleaner New Zealand.

Whether it’s upgrading a water tank or installing a new water system, we always offer bespoke solutions designed to fit your environment and lifestyle. Take a look at our recent projects to be inspired.

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Our clients came with the mission of creating their own passive solar home. The NaturalFlow system was an obvious choice, being power-free. We were able to help them achieve their dream on this awesome property.

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Family Home

The EconoTreat was perfect for this family home. With higher volumes of waste and council requirements of secondary treatment, they needed a system that would provide a consistently high treatment.

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Packhouse Accomodation

With large seasonal fluctuations, this kiwifruit packing facility needed capacity for peak season staff. A custom designed system by WaterFlow met the requirements for the project, with the capacity to process up to 54,000L per day.

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Otamatea Marae

Struggling to have enough water to sustain the events, we were asked to upgrade the water tanks and drainage. With an additional four 25000L tanks, they aren’t likely to run out any time soon!

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Rural Oasis

The Naturalflow NF8000 System was used in this piece of paradise. The landscaping gives it a tropical feel, as you step through to the pool for some quality time out.

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With major upgrades to the building and facilities, the Spiritual Assembly of the Bahai’s was in need of an upgraded wastewater system.

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"Everyone in your team from your sales, design and the delivery guy has been so knowledgeable and fantastic to deal with.

Everyone that has been here for site visits and install have been so easy and a pleasure to deal with. So much so we are choosing you guys to do it all over again with."

Jo - Kaukapakapa February 2023

"Kia ora, I've been dealing with many different aspects of getting a small house built for us on our section for the last couple of years, and it's taken a long time because so many people we have engaged have been slow or unprofessional in their work.

The two people who really stand out as complete contrast to this work for you - both Caleb and Sandra have been nothing but absolute treasures in this process. They have been professional, knowledgeable, helpful, and extremely patient. We could not be happier with their work.

Thank you for employing such excellent staff."

Joey - Waitakere January 2023

"A big thank you for Adam’s efforts today. He braved the rain and very efficiently checked the system, repaired the two leaks and also helped us out with some paper work. You have a good set up.

Thanks again and best wishes to you and the team there."

Tony - Waipapa November 2022

"I have found your entire staff a pleasure to deal with.

Your first contact personnel, sales people, sales support and installation team have been very helpful and courteous; nothing has been a problem they can’t fix."

Frank - Riverhead June 2022

"Thanks for getting Adam out so quickly today.

FYI, he was extremely helpful in explaining the system etc and I really appreciated his approach and advice."

Paul - Waipapa June 2022

"Yesterday while your workers were at 90 Opito Bay Rd the elderly gentleman owner had a fall grazing his knee and appeared to be a little confused. Some how, someone went to the extra caring mile to find a contact to alert his accident to family.

I want to acknowledge this wonderful & heartwarming humanity with a big thank you. Above and beyond great service!"

Chris - Kerikeri May 2022

"Waterflow n.z. supplied and installed the wastewater system on our lifestyle block completing it on the last working day before the Christmas holidays.

We love the system and were very satisfied with the installation and service. They were great to deal with and left us feeling confident in future servicing and maintenance."

Peter - Whananaki March 2022

"We've been really impressed with the service and professionalism from your team - thank you.

Gary also did an excellent job, very tidy, great to communicate with, and happy to accommodate our requests."

Lauren - Waimauku February 2022

"The biggest thanks to you and your team. You have all been an absolute pleasure to work with and would highly recommend at any time to everyone. Thank you all.

We are so stoked with the outcome and can’t wait for the system to get up and running. A massive thanks to Gerald too for taking the time to educate me in all the ins and outs of sewage – all of you were all so helpful and made the process sooo easy."

Rebekah - Kaipara Flats December 2021

"Water Flow has been an absolute pleasure to work with from start to finish.

Everyone has been knowledgeable, friendly and professional. Your contractors are excellent, highly skilled and very professional. Communication has been exceptional

I have no hesitation in using your services for our new house system and would highly recommend your services in the future."

Andrew Chapman - Hakaru September 2021

"Gavin was great during the installation and so far all has gone well so thanks.

The site has been left well-groomed and with minimal mess, which considering the time of year and amount of water around is very much appreciated."

Aaron - Kaiwaka August 2021

"Thank you for making it such a smooth process with excellent communication and even better customer service.

You arrived on time, completed the work to a high standard and caused no issues for us. Thank you must go to you all."

Otamatea Marae April 2021

"We are happy with the installation of our septic system thanks.

The speed from us saying that we were ready for the installation and the job being completed was great. Also the site being left in a nice clean state was exceptional.

Great people all round to deal with. Thank you"

Meghan and Keith - Kaipara October 2020

"Thank you for your services, you have an excellent working crew and you all in the offices there made the whole paperwork and organizing of the job processes so easy for me it was so good to leave it in your hands and not be doing it myself, as I had to with the rest of the stuff I’ve had to do during this time."

Thelma - Ruawai June 2020

"To Whom it May Concern Our Papakainga in Pouto (currently 8 homes on site) had major septic issues and due to Health & Safety reasons the Council was justified in demanding an upgrade.

Natural flow provided an environmentally sustainable system that uses a natural process to treat our wastewater to a very high standard. This was extremely important to us as the Papakainga lies adjacent to the Kaipara Harbour.

To date we have experienced great service and maintenance of the system and the Council is happy too."

Pouto Papakainga – Pouto March 2020

"Thank you very much for the work & installation of your system.

It was a pleasure to see how fast, efficient and what an excellent job they have done, nice and tidy job too, very impressive thanks again, I will enjoy using this system knowing that it's environmentally friendly too."

Victoria - Tinopai July 2020

"Just wanted to add that you guy's have been amazing throughout this process, Gerry has been so great to deal with, himself and the other two guys were super efficient and very tidy completing the job on site and it was done on time even with my dates getting pushed out and not 100% confirmed until about a week out from the house arriving on site it felt like it was no issue to Gerry and he was very accommodating.'

Emily - Hatuma November 2019

"I have to say i am very impressed by your work done given what was the potential. I agree i think its fairly late in the season to worry too much about Grass recovery and if it does need a bt of a help it won’t be until closer to spring anyway, but for now its looking good.

Thanks again. We can touch base later around that. Thanks again, were really impressed by your Company.

I would have absolutely no hesitation in recommending anyone in both the product and your after care support. We really appreciate it!"

Mark - Te Kauwhata June 2019

"I would also like to thank you guys for your exceptional customer service. we have been impressed by the professional attitude by your team.'

Glenn - Ruawai June 2019

"I just wanted to say ‘thank you’ for sending two such lovely, competent men (Hamish & Rangi) to repair our septic waste water field.

They were 100% professional and a real credit to Natural Flow."

Leesa - Whangteau May 2019

"We have been super happy with our new Wormerator. The guys were absolutely awesome on the installation. Jimmy, Terry and Rick were so hardworking, thoughtful and friendly.

They have done an outstanding job. Mary Kay was also very helpful in all our communication."

Jessica - Ngunguru January 2019

"ust a quick note to thank you guys for doing such a great job for us. You made the process very clear from the outset and kept us totally informed along the way.

The drain layers turned up when they said they would, worked in appalling conditions and came back to finish off without a grumble. I wish all our dealings had been so trouble free.

Thanks again to you, Ken, Garry and Terry the drain layers and your team."

Warren - Kumeu September 2018

"Stoked with the work done, the boys on the diggers did an awesome job. Everything was left nice & tidy, super happy!!"

Cullen - Stillwater November 2017


Protecting the Future of Your Property and our Shared Backyard
At WaterFlow we are with you from start to finish – and beyond. Once installation has finished, we are still on hand to provide, maintenance, support and servicing.

Discover ways to maintain your systems in between servicing and how to contact our expert service technicians.


All you need from first inspection to post-install support

For trade professionals, working with WaterFlow means gaining a reliable lifelong partner committed to achieving project success, and a team that values collaboration, precision, and timely execution.

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Your site and dispersal field have the biggest say in which system will work best for you. Let our team take a look, either on site or via aerial mapping, and we can help you find a solution that works for you.

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