Dairy Effluent Warrant of Fitness

The Effluent WOF programme consists of a voluntary, independent inspection of a farmer’s effluent infrastructure and practices.

After extensive testing with over 200 farmers, Effluent WOF is now available to farmers and rural professionals around the country.

The Effluent WOF programme is insightful and practical, covering the entire effluent system.

An independent assessor points out areas of risk and suggest practical actions a farmer can take to ensure their system is capable of being compliant 365 days a year.

A 3-4 hour assessment by the accredited assessor covers the farm’s effluent consents and permitted rules, the storage capacity, nutrient loadings, soil risk, irrigator performance, off-pasture infrastructure and general health and safety requirements.

All WoF Assessors are trained professionals who are fully certified as Warrant of Fitness Assessors. Every assessor has completed the Farm Dairy Effluent System Warrant of Fitness Course and a subsequent field assessment.


  • Buying or selling a farm?

    Know if the system is fit for purpose or if you need to factor upgrades into the offer.

  • Are you a share milker coming onto a property?

    Find out what the risk is for your farm.

  • Upgraded the effluent system yourself?

    Find out how well the effluent system is performing and reassurance that your system is fit for purpose.

  • Budgeted for an upgrade to the system?

    An independent person who assesses the current system will help with decision making.

  • Did you know?

    Corporate Board members and absent owners can be liable if there is inadequate effluent infrastructure on a farm.

Murray McEwan

McEwan Ag-Nutrients Ltd 

McEwan Ag-Nutrients Ltd
This email address is being protected from spambots. You need JavaScript enabled to view it.
027 265 3838

I has been involved with farm nutrient management for 20 years and have experience with all dairy farming systems and the associated effluent systems that are applicable to that particular farm. Effluent system design is not just about a big storage solution, there are a variety of options that should be assessed to ensure a fit for purpose outcome. I operate independent of any product supplier. 

My qualifications are 

  • Intermediate & Advanced Sustainable Nutrient Management qualifications from Massey
  • Effluent System Design & Management also from Massey
  • Effluent Pumping & Hydraulics from Massey

This experience & these qualifications are all applied to consenting processes for regional councils and as an independent operator of the Overseer Nutrient Budget programme.


Certified WOF assessors offer a very thorough and consistent assessment of effluent systems.

A certified assessor is an independent, experienced industry professional.

To become certified, the assessor has completed a three-day training course and passed a competency assessment process.

The assessor is committed to observing a Code of Conduct to guarantee professional behaviour and independent advice.

Certified WOF Assessors use the same methodology every time.


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The assessment includes the farm's effluent consents and permitted rules, storage capacity, nutrient loadings, soil risk, and health and saftey..

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