Best practices for storing fuel for generators
Peter Sitkowski | 30th March 2026 | 8 minutes to read
Proper fuel storage is one of the most overlooked aspects of generator ownership. Whether the unit is reserved for emergency backup, remote touring, or worksite duties, the condition of the fuel inside it plays a critical role in reliability and longevity.
Storing fuel correctly is not just about keeping it in a container and hoping for the best. It requires an understanding of fuel chemistry, safe containment, environmental factors, and rotation practices. After all, a generator is only as dependable as the fuel feeding it, and stale or contaminated fuel has a habit of revealing itself at the worst possible moment.
This guide outlines the essential principles of safe, efficient, and long term fuel storage for generator use:
Understanding Fuel Types and Shelf Life
Generators commonly operate on unleaded petrol or diesel, and each fuel type behaves differently over time. Petrol is more volatile and generally has a shorter shelf life, often beginning to degrade within a few months if left untreated. Diesel is comparatively stable, but it is still susceptible to oxidation and microbial growth when exposed to moisture.
Fuel degradation can result in gum formation, varnish deposits, and reduced combustibility. In practical terms, that means difficult starting, rough running, or complete failure to operate. Ethanol blended petrol introduces further complexity, as ethanol attracts moisture from the air, increasing the likelihood of phase separation and corrosion within the fuel system.
Understanding these characteristics allows generator owners to plan storage intervals appropriately. For those regularly travelling in remote areas or relying on backup power during outages, browsing suitable fuel and water storage solutions can help ensure fuel remains viable and secure for extended periods.
Choosing the Right Storage Containers
Not all containers are created equal. Approved fuel containers are specifically designed to withstand expansion, reduce vapour loss, and prevent leaks. Using compliant containers significantly lowers the risk of fire, contamination, and environmental damage.
High quality metal or heavy duty plastic containers with secure seals are preferred. For portable applications, especially in off road or touring environments, purpose built jerry cans offer durability and safe transport. They are engineered to manage pressure changes and rough handling, which makes them ideal for both stationary storage and mobile setups.
When selecting a container, consider the following:
- Capacity appropriate to expected usage
- Compliance with local safety standards
- Airtight, leak resistant caps
- Clearly marked fuel type labels
It may be tempting to reuse old containers for convenience, but this approach often leads to contamination or evaporation losses. In fuel storage, proper equipment is not a luxury, it is a necessity.
Storing Fuel Safely and Legally
Fuel must always be stored in a well ventilated area away from ignition sources, direct sunlight, and living spaces. Heat accelerates chemical breakdown and increases internal pressure within containers, while poor ventilation raises the risk of vapour accumulation.
Ideally, fuel should be kept in a cool, dry location such as a detached shed with adequate airflow. Containers should remain upright on stable surfaces to prevent tipping or damage. Even in well organised camping setups, fuel should be positioned well away from cooking equipment, open flames, and battery systems.
Basic safety measures include:
- Keeping fuel out of reach of children
- Storing away from oxidising agents and chemicals
- Maintaining appropriate fire extinguishers nearby
- Observing quantity limits set by local regulations
While regulations vary, adhering to conservative storage volumes and prioritising safety best practice is always advisable. A generator may provide convenience, but mishandled fuel introduces unnecessary risk.
Preventing Contamination and Degradation
Contamination is one of the primary causes of generator fuel system issues. Dirt, water, and microbial growth can infiltrate storage containers if they are not properly sealed or maintained. Even minor contamination can clog carburettors, block injectors, and damage internal components.
To minimise degradation, many operators use fuel stabilisers. These additives slow oxidation, inhibit gum formation, and extend usable life. Stabiliser should be added to fresh fuel prior to storage, following manufacturer dosage recommendations. Simply pouring stabiliser into old fuel rarely restores it to optimal condition.
Water management is equally critical, particularly for diesel. Condensation can form inside partially filled containers due to temperature fluctuations. Keeping containers as full as practical reduces air space and limits moisture accumulation. This is especially relevant for vehicles and generators used in caravan touring, where varying climates and storage durations are common.
Routine inspection is a sensible habit. If fuel appears cloudy, darkened, or has a sour odour, it is likely degraded and unsuitable for use. When in doubt, it is better to dispose of compromised fuel safely than to risk mechanical damage.
Fuel Rotation and Maintenance Practices
Even with stabilisers and high quality containers, fuel should not be stored indefinitely. Implementing a rotation schedule ensures that stored fuel remains fresh and usable. A common strategy involves labelling each container with the purchase date and using the oldest supply first.
For generators maintained as emergency backup systems, periodic testing is essential. Running the generator under load every few months circulates fuel through the system and confirms operational readiness. This practice also highlights any developing issues before they become critical.
Effective rotation practices include:
- Marking containers with fill dates
- Limiting petrol storage to a few months without stabiliser
- Inspecting seals and vents regularly
- Draining and replacing stale fuel promptly
It might sound meticulous, but a small amount of organisation prevents significant inconvenience later. Few situations are more frustrating than a silent generator during a blackout.
Preparing Generators for Long Term Storage
In addition to managing stored fuel, the generator itself must be prepared for inactivity. For petrol units, shutting off the fuel supply and allowing the engine to run until the carburettor is dry can prevent residue build up. Alternatively, draining the tank entirely may be appropriate for extended storage periods.
Diesel generators benefit from full tanks during storage, as this reduces internal condensation. However, fuel condition must still be monitored, and stabiliser may be recommended depending on anticipated downtime.
Other long term storage considerations include:
- Changing engine oil before storage
- Cleaning or replacing air filters
- Disconnecting or maintaining batteries appropriately
- Covering the unit to protect against dust and moisture
Ultimately, best practice fuel storage is about foresight. Clean, stable fuel stored in appropriate containers, combined with routine inspection and rotation, ensures that a generator will perform when required. It is a straightforward discipline, yet one that pays dividends in reliability, safety, and peace of mind. And when the lights go out or the campsite needs power, that preparation suddenly feels very worthwhile.
