Diesel and petrol tanks on farms: what the rules require

Most farms keep fuel on site, often a diesel tank by the shed and sometimes a petrol tank or drums for bikes and small engines. The Health and Safety at Work (Hazardous Substances) Regulations 2017 treat farms a little differently from other workplaces, and WorkSafe's guideline on above-ground fuel storage on farms sets out how. For these rules, a farm is an area of land of at least four hectares. Smaller lifestyle blocks follow the general rules, which are stricter.

Does the tank need a compliance certificate?

A stationary tank and the pipes, hoses and dispenser attached to it form a stationary container system. Above certain sizes the system needs its own compliance certificate from an authorised certifier:

• an above-ground tank holding more than 2,500 litres of petrol
• an above-ground tank holding more than 5,000 litres of diesel
• a tank supplying an engine, from 500 litres for diesel or 50 litres for petrol
• a tank supplying a burner, from 60 litres

How long the certificate lasts depends on the tank. Under WorkSafe's 2018 safe work instrument on validity periods, a single-skin tank of up to 250,000 litres with secondary containment of 110% runs for five years, and a double-skin tank with a monitored interstitial space runs for seven years on its first certificate. Where nothing else sets the period, the certificate is valid for one year.

Does the farm need a location compliance certificate?

Diesel never needs a location compliance certificate. Petrol on a farm needs one if more than 2,000 litres is stored at a single location. Below that, petrol is exempt as long as the tank is certified, sits at least 20 metres from protected places such as houses and 6 metres from anything combustible, and is placed so a spill can't reach buildings or water.

Distances, containment and the dairy shed

WorkSafe's guideline sets separation distances for petrol and diesel tanks, and they differ between steel and plastic diesel tanks, so check the tables in the guideline for your setup. Two rules apply widely. A plastic diesel tank must be at least 6 metres from an ignition source, and other fuel tanks at least 15 metres. Bulk fuel must also be at least 20 metres from a farm dairy, which comes from the dairy code of practice under the Animal Products Act.

Secondary containment, such as a bund or a double-skin tank, isn't needed for less than 2,500 litres of fuel in a tank or less than 2,000 litres in drums at one location. Above that, the tank needs containment that will hold a spill.

Signs, extinguishers and an emergency plan

Put up hazardous substance signs if you hold more than 2,000 litres of petrol or 1,000 litres or more of diesel at one location. Fire extinguishers must be rated at least 30B, which a 2 kg dry powder or 9 litre foam extinguisher meets. Petrol needs one from 50 litres and two from 200 litres, and diesel needs two from 500 litres.

A written emergency response plan is needed once the farm holds more than 2,000 litres of fuel. It must be tested at least once a year. Our guide to emergency response plans covers what goes in it.

A worked example

A sheep and beef farm keeps an 1,800 litre steel diesel tank by the shed. The tank doesn't need its own compliance certificate, because the line for an above-ground diesel tank is 5,000 litres, and the farm doesn't need a location compliance certificate, because diesel never does. At 1,800 litres it is below the 2,500 litres at which secondary containment is required and below the 2,000 litres that would call for a written emergency plan.

It does need hazardous substance signs, since it holds more than 1,000 litres of diesel, and two fire extinguishers rated at least 30B, since it holds more than 500 litres. As a steel tank it must be at least 15 metres from an ignition source. A tank that feeds an engine directly, such as a generator, has a much lower line for certification, from 500 litres of diesel.

Getting a farm tank certified

HSWNZ certifies above-ground and below-ground tanks for petrol and diesel up to 120,000 litres, and works nationwide. Tell us the tank size, what's in it and where it sits, and we'll tell you what it needs before we book the visit. Book a tank inspection.

This is general guidance based on WorkSafe's published material. It is not legal advice, and the regulations take precedence where they differ. WorkSafe's farm guideline and its farm fuel checklist differ on some figures; the guideline is used here.

Sources

1. WorkSafe New Zealand. "Above Ground Fuel Storage on Farms." Last modified 7 October 2021. Accessed 16 October 2026. https://www.worksafe.govt.nz/topic-and-industry/agriculture/chemicals-and-fuels-on-farms/above-ground-fuel-storage-on-farms/.
2. WorkSafe New Zealand. "Stationary Container System Compliance Certificates." Last modified 11 January 2021. Accessed 16 October 2026. https://www.worksafe.govt.nz/topic-and-industry/hazardous-substances/certification-authorisation-approvals-and-licensing/certification-of-equipment-plant-buildings/stationary-container-system-compliance-certificates/.
3. WorkSafe New Zealand. Health and Safety at Work (Hazardous Substances—Validity Periods of Compliance Certificates for Stationary Container Systems) Safe Work Instrument 2018. Accessed 16 October 2026. https://www.worksafe.govt.nz/dmsdocument/3792-safe-work-instrument-validity-periods-of-compliance-certificates-for-stationary-container-systems/.
4. WorkSafe New Zealand. "Diesel." Last modified 29 September 2021. Accessed 16 October 2026. https://www.worksafe.govt.nz/topic-and-industry/hazardous-substances/guidance/substances/diesel/.
5. Health and Safety at Work (Hazardous Substances) Regulations 2017 (LI 2017/131), reg 5.6. New Zealand Legislation. Accessed 16 October 2026. https://www.legislation.govt.nz/regulation/public/2017/0131/latest/whole.html.