Advanced wastewater treatment, built for the hardest sites in the country.
A Gradient Drainage installs and supplies Kubota Wastewater Treatment Plants across New Zealand. Kubota Design and manufacture Japan's most trusted residential wastewater technology. A Gradient Drainage is family-owned, certified, and specialises in difficult sites.
Certified Drainlayers
New Zealand
Kubota
Wastewater
Suppliers
Nationwide Installer Network
Island drainage is a different game. We built our business around it.
Difficult-site wastewater is what we do. We built that expertise on the Hauraki Gulf islands, sloping sections, tight access, sensitive coastal environments, and councils that expect a higher standard of treatment, where a standard septic tank simply won't do and we now bring it to projects nationwide.
A Gradient Drainage is a family-owned and operated team, hands-on from the first site visit to long-term maintenance. We supply, install, commission, and service complete systems, so you've got one point of contact the whole way through.
Now installing the Kubota Wastewater Treatment Plants in New Zealand
Kubota, a name in water technology since 1890. It's tested under Japan's Johkasou Framework, one of the world's most demanding residential wastewater standards, including a cold-temperature test at 13°C that AS/NZS guidelines don't require. In plain terms: it's engineered to keep treating reliably through a New Zealand winter. From residential one-bedroom units to large-scale commercial utility plants and everything in between, Kubota wastewater has you covered.
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That reliability is proven at a scale almost no other manufacturer can match. Kubota produces more than 50,000 treatment plants a year, with over 10 million systems installed worldwide, running everywhere from Europe, North America and Asia to the Middle East and Australia, and now New Zealand through our partnership with True Water, Kubota's distributor across the Pacific. Some Kubota plants installed in the 1960s are still treating today, more than 50 years on.
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30+ year engineered design life, units installed in Japan in the 1970s still run today
Near-silent blower and gas-tight covers, no odour, no noise nuisance
Compact, lightweight FRP build, that suits sloping ground and tight island sections
91% BOD removal across a six-stage treatment process
Our Services
Specialists, not generalists
Difficult-site expertise
Years of working the hardest sections on Waiheke and the Gulf islands.
One team, start to finish
Supply, install, commission, service. No handoffs, no finger-pointing.
Compliance handled
We know what Auckland Council expects under GD06 and prepare your documentation accordingly.
“We have been very pleased with the service and professional approach from A Gradient Drainage who installed a 3 tank system for us. They delivered on time and on budget.”
Ian Kuperus
Address
117B Onetangi Road, Onetangi Waiheke island.
Phone
0273833949
