Read our expert guide for everything diesel storage related from the types of diesel tanks available, storage regulations, how to get the best price on fuel and preventing fuel theft. We’ve been manufacturing tanks for the storage of diesel for national and international clients for over 30 years and we’ve tried to sum up this knowledge in this expert guide.


What are diesel and biodiesel fuels?

Diesel is a liquid fuel and has been used to power combustion engines for around 100 years.

However, diesel has a high carbon intensity and so releases large levels of CO2 into the atmosphere. This has led to the production of biofuels which are fossil-free, more sustainable and have a lower carbon intensity.

Mineral diesel
Mineral diesel fuel is a mixture of hydrocarbons obtained by the distillation of crude oil. Unlike a spark-ignited petrol engine, diesel engines are ignited by the heat generated through air compression. Diesel is a fossil fuel with a high carbon output meaning it’s non-renewable, releases harmful greenhouse gases in to the environment when burnt and we will eventually deplete the world’s diesel reserves.

Biodiesel is an alternative to conventional diesel. As biodiesel is primarily derived from plants it’s considered a renewable resource. Usually, the biodiesel FAME is blended with ordinary diesel and works in most diesel engines without the need for engine modification. Because the UK government
aims to reduce vehicle emissions (and burning biodiesel releases lower emissions than conventional diesel) it is most commonly used in transport.

Hydrotreated Vegetable Oil (HVO) is a second generation biofuel meaning it derives entirely from waste animal and vegetable products and therefore is fossil-free and sustainable. In most cases, HVO is a drop-in alternative to diesel and boasts a reduction in greenhouse gas emissions on up to 90%. For more information, view our Expert guide to HVO fuel tanks.

diesel fuel

What are the diesel storage regulations?

Everyone storing oil (including diesel, biodiesel, kerosene and petrol) in a container with a capacity of over 200 litres must follow oil storage regulations. The exact regulations that apply to you depend on the quantity of diesel you are storing, whether it’s used for commercial or domestic applications, and the country in which your diesel tank resides.

Oil storage regulations for diesel storage tanks specify whether the tank is required to have a secondary containment, often called a “bund”. A bund is an outer container surrounding the inner tank which stores the fuel and is required to have a capacity of at least 110% of the inner tank. The bund works to catch any spillages from the inner tank and reduces the risk of oil contaminating waterways and the environment.

Do I need a bunded diesel tank?
While the vast majority of commercial and agricultural tanks must have a bund, not all domestic locations do. View the table below to see if you need a bunded tank.

Domestic diesel storage regulations
In England, oil stored in containers with a capacity under 3,501 litres used for domestic applications aren’t required to have a secondary containment unless they are sited in locations where oil spills can reach public water sources. This includes:

• Where oil spills could run over hard ground and reach coastal waters, inland fresh waters or a drinking water source.
• Where oil spills could run into an open drain or a loose manhole cover.
• Where the tank vent pipes cannot be seen when the tank’s being filled, for example, because the delivery tanker is parked too far away.
• Within 10 metres of coastal waters or inland fresh waters like lakes or streams.
• Within 50 metres of a drinking water source, for example, wells, boreholes or springs.
• In the inner zone of groundwater source protection zone 1

While in these circumstances a bund isn’t compulsory, we still recommend bunding all tanks as good environmental practice. Additionally, when you install a single skin tank you face the risk of regulation updates making your tank no longer compliant.

Commercial diesel storage regulations
Commercial oil storage regulations must be followed if your business (including marinas and public sector premises) stores oil in a tank with a capacity of 201 litres or higher, or if your domestic premises stores oil in a tank with a capacity over 3,500 litres. Regulations state that all commercial diesel tanks must be bunded.

Agricultural diesel storage regulations
Diesel stored for agricultural usage follows slightly different rules in England. Diesel storage containers with a capacity over 1,500 litres must be bunded. Additionally, no part of the oil storage installation – including yard drains, dry ditches and land drains – can be within 10 meters of inland or coastal waters.

Diesel storage regulations in Wales, Scotland and Northern Ireland

With an increased focus on protecting the environment oil storage regulations are becoming increasingly strict and new regulations in Wales now require all new oil tank installations with a capacity over 200 litres to be bunded. In Scotland all oil tanks with a capacity above 2,500 litres must to bunded. Diesel tanks in Northern Ireland follow the same secondary containment requirements as England and must be bunded when above 2,500 litres. Tanks in Scotland and Ireland used for agricultural applications with a capacity above 1,250 litres must be bunded.

To find out more about diesel storage regulations in your country click on the appropriate link:

Diesel Storage Regulations England
Domestic and commercialControl of Pollution (Oil Storage) Regulations 2001
AgricultureStoring Silage, Slurry & Agricultural Fuel Oil
Diesel Storage Regulations Wales
Domestic and commercialControl of Pollution (Oil Storage) Regulations 2016
AgricultureControl of Pollution (Oil Storage) Regulations 2016
Diesel Storage Regulations Scotland
Domestic and commercialThe Water Environment (Controlled Activities) Regulations 2011
AgriculturePrevention of Environmental Pollution from Agricultural Activity
Diesel Storage Regulations Northern Ireland
Domestic and commercialControl of Pollution (Oil Storage) Regulations 2010
AgricultureSilage Slurry and Agricultural Fuel Oil Storage

Diesel storage tank manufacturing and quality standards
All diesel tanks should meet British Standards and trade association standards. At a minimum, tanks need to comply with BS EN ISO 9001, should be made of a material suitable for the oil stored with sufficient strength to ensure it won’t burst or leak with ordinary use and are expected to last at least 20 years with proper maintenance. Rotationally moulded polyethylene tanks must also meet BS EN 13341 standards and be CE marked to indicate conformity with health, safety and environmental protection standards. Steel tanks must meet BS 799 standards. Your manufacturer, supplier, or installer should advise you on whether a tank meets these standards.

What are the advantages of owning a diesel storage tank?

Diesel storage tanks are commonly used when a business requires onsite fuel storage to fuel a fleet of vehicles or other machinery. Owning your own diesel tank is often a prudent decision to save time, reduce costs, improve the efficiency of operations, or all three. The benefits of private diesel storage and dispensing depends upon the industry, but for industries such as agriculture and uses such as Uninterruptible Power Supply (UPS) it’s usually a necessity.

Bulk diesel storage
For fleet operators who regularly use large quantities of diesel, bulk fuel storage is essential. Buying fuel in bulk also reduces the price you pay per litre and gives enables businesses to bulk buy their fuel when prices are low. This is especially important for the transport industry where small savings are multiplied over dozens, hundreds, or thousands of vehicles.

On-site diesel storage
Having a diesel tank onsite reduces time queuing at forecourts while offering haulage companies greater protection from the risk of fuel shortages. For industries such as agriculture, storing red diesel onsite is a necessity for non-road vehicles which can’t legally use red diesel on public roads.
HVO is not currently available at UK forecourts so anyone using HVO biofuel must also have a private tank.

Fuel management systems
One of the biggest benefits of fuel tanks for fleet operators is the tanks synchronisation with a fuel management system. This enables a company to control and monitor fuel consumption for cost analysis and to improve fuel efficiency. We supply a pulse meter with every steel tank and can also fit a Fuel Management System to get detailed fuel consumption data for drivers and vehicles.

Generator diesel tanks
Diesel tanks can be used for variety of purposes such as feeding back-up generators to power hospitals and city councils for emergency electricity in the event of a blackout. We recently manufactured two 30,000L tanks for an NHS COVID testing facility known as a ‘Lighthouse Lab’. Health and safety regulations and the need for quick COVID results meant that two backup generators were required.

What are the disadvantages of owning a diesel storage tank?

The biggest reason not to invest in your own diesel tank is often that you are taking the responsibility of storing your own fuel – rather than letting the fuel station take the risk. Probably the greatest risk is fuel theft. Thousands of litres of diesel amount to a small fortune and can be a target for would-be thieves. For someone with a very secure yard sited in a quiet area theft may not be a big issue. If that isn’t you, then this is a serious consideration. Check the crime rates in your area to see if theft has been a big problem.

Another reason not to own your own diesel tank is the risk of oil spillage. Oil leaks can also occur due to human error or damage to the tank. Decontaminating the area after an oil spill can cost thousands. However, there are ways to avoid oil spills. Providing a secondary containment will capture oil leaks from the inner tank. Additionally, steel provides greater impact resistance for tanks and Armco barriers offer additional protection for plastic and steel tanks.

What types of diesel storage tanks are available?

Diesel storage comes in a variety of types and sizes from drums and bowsers to above-ground diesel tanks and underground tanks. As above-ground diesel tanks are made for bulk liquid storage they tend to be used commercially. These are available for regular diesel and biodiesel, in plastic (polyethylene) and steel. Our standard tanks are available in sizes from 1,350 litres to 100,000 litres.

Bunded diesel tanks
Bunded diesel tanks have two layers – an inner tank and an outer tank (bund) which acts as a secondary containment (a tank within a tank). In the event of a leak from the main tank, the outer layer will contain all the oil which would otherwise risk contaminating the local area. Integrally bunded tanks are the most popular kind of secondary containment. The alternative involves constructing a bund from masonry or concrete which is inconvenient, costly and makes a time-consuming installation. All of our diesel tanks are bunded.

Plastic diesel tanks
Our polyethylene diesel tanks are manufactured from a durable UV-stabilised and corrosion resistant polymer. Plastic tanks are a hardy but more cost-effective alternative to steel tanks. To increase the strength of our plastic tanks they are roto moulded – a process which creates a single unit without joints and seams which create weaker areas. Our bunded plastic tanks have a design life of at least 20 years and hold a 10 year warranty.

Steel diesel tanks
Steel diesel tanks are more expensive to manufacture than plastic but offer greater adaptability and have a design life of 30 years with a 10 year warranty Generally steel diesel tanks are made to order meaning they can meet bespoke requirements, capacities and dimensions. This makes steel tanks popular with people who need to install a diesel tank to fit into an exact area such as those who want to replace a tank with the same footprint. Because steel tanks are fabricated by hand and don’t rely on moulds they can reach a much bigger capacity than plastic tanks. Our steel tanks are available in capacities up to 100,000 litres.

Biodiesel tanks
Our existing range of plastic and steel diesel tanks is compatible with biofuels such as HVO. To check our tanks’ compatibility with other biofuels simply contact [email protected] with details on the fuel.


How do I get the best diesel prices?

The price of diesel fluctuates for many reasons including demand, the exchange rate, natural disasters, and political unrest. By buying diesel in bulk while prices are low, those with diesel tanks can benefit from these fluctuations.

Buying diesel when prices are low
The average price of diesel over the past decade in the graph below shows how much prices can vary and the reasons for the variance. In July 2020 (during COVID when demand was low) the average forecourt price of diesel was just £114.95 compared to two year later (during political tensions with Russia) in July 2022 with the average prices reaching £198.84 at the month’s beginning.

While long-term fuel price fluctuations are almost entirely unpredictable you can often save money by purchasing fuel at the right time of year. The graph below shows a breakdown by month of the average price of diesel. While you can’t guarantee cheaper fuel at a given month, prices tend to drop after the Christmas period. This means January and February are often the best time to purchase. With a difference of 3.88p per litre between February and October, purchasing 25,000 litres of fuel at the right time will save you nearly £1,000.

Fuel management systems & improving fuel efficiency
Getting the best price for diesel doesn’t end after you’ve purchased the fuel – it’s also about improving fuel efficiency to get the most value out of every litre. That’s why our plastic and diesel fuel stations are available with a Horn fuel management system which gives you greater control and fuel consumption monitoring abilities. The data provided can identify underperforming vehicles or drivers who would benefit from additional training.

What size diesel tank do I need?
To get the lowest diesel prices possible we recommend purchasing the highest capacity tank you feasibly can. This is because fuel suppliers offer incremental savings on the price you pay per litre – the more diesel you buy, the lower the cost per litre. A mainstream national fuel supplier we contacted had incremental savings for purchasing diesel in these quantities: 500L, 900L, 2000L, 4500L, 7500L, 10000L, 15000L, 18500L, 24000L, 30000L and 36000L litres. The cost of fuel delivery must also be accounted for, even if the cost is ‘hidden’ in the fuel’s price. The longer your fuel lasts, the less you pay for delivery. Additionally, larger tanks mean you can benefit more from purchasing fuel while prices are at their lowest.

Tuffa manufacture the largest plastic bunded diesel tanks in the UK including the 10000 litre diesel tank and a 15000 litre diesel tank available as a single unit or 30,000 litres with interlinking. While plastic tanks will gives you the lowest cost per litre of storage, we also have steel diesel tanks available in high capacities up to 100,000 litres.

Where can I bulk buy diesel from?

There are many fuel suppliers in the UK offering regional or national delivery. Unfortunately, bulk diesel seems to be the only product which doesn’t appear on price-comparison websites. This puts the onus on you to shop around and find the best deal. Initially, you want to check the fuel supplier delivers the quantity of fuel you require; a typical minimum order is 500 or 1,000 litres. It’s also worth getting quotes from regional and national suppliers as, with the inclusion of delivery, the prices will vary.

Once you’ve shortlisted the top diesel suppliers and received a quote from each it’s well worth pitching the top few against each other to lower the price.

How long can diesel be stored for?

Diesel can be stored for between 6 and 12 months without the need for additives. The rate of sediment buildup, and therefore the storage life of the fuel, depends upon the condition it’s kept in. Ideally, diesel should be kept below 20°C, out of direct sunlight (especially for polyethylene tanks), and free from water. If diesel is kept in these optimum conditions, then the degradation process can be decelerated and diesel can be stored for up to a year.

How long can biodiesel be stored for?
Like conventional diesel, oxygenation, heat and water degrades FAME (Fatty Acid Methyl Ester) biodiesel. FAME is more susceptible to oxygenation and contamination from microorganisms, accelerating the degradation process. In optimum conditions biodiesel can be stored for up to four or five months but this can be extended with the use of additives.

While FAME is a first-generation biodiesel, HVO is second-generation and is hydrotreated which removes the oxygen from the fuel and significantly reduces the rate of degradation. HVO can be stored for up to 10 years.

How to prolong the lifespan of diesel
As well as keeping your tank cool and free of water there are a number of initiatives which will help to prolong the lifespan of your diesel:

• Keep away from copper, zinc and other metal alloys
• Fuel maintenance programmes and regular maintenance of the diesel storage tank
• Keep your storage tank free from condensation
• Empty and clean your tank fully, at least, every ten years
• Use thoroughly refined fuel, for better stability
• Use additives which help to aid the safe storage of your fuel; from metal de-activators, fungicides, biocides, antioxidants and fuel stability foams.

How do I maintain a diesel storage tank?

To help achieve the tank’s full design life and reduce the risk of a leak, it’s vital to ensure that diesel tanks are maintained and inspected on a regular basis by a competent person. Diesel tanks, particularly those storing gas oil with a high percentage of FAME, may also require a fuel maintenance program to detect and remove water.

Checking your diesel
It’s recommended that you check your diesel tank on a monthly basis and after any episodes of extreme weather. Some of the visible signs you should look for on the tank include:

• The fill point arrangement for soundness and leaks
• Any outlet valves should be checked for leaks and operation (open and close successfully)
• The testing of contents gauge, any high level / overfill alarm and bund alarm.
• If vents can be seen that they are clear and unblocked and free of debris.
• A visual inspection around the tank with emphasis on the base of the tank.

The inspection for plastic tanks should include any deformation of the surface of the tank such as:

• Excessive bulging
• Change in colour due to chemical attack
• Crazing or stress fractures.
• The inspection of steel tanks should include looking for evidence of:
• Rust and heavy corrosion
• Damp patches on seams & seam fractures.
• The bund to be visually inspected for soundness and integrity, water, spilt product, or other debris.

Fuel maintenance program
Diesel stored over a long period of time will deteriorate. This causes a slimy residue made from bacteria, algae and fungi, sometimes known as ‘diesel bug’, to appear in your tank. Often the first sign of this is when filters become blocked on dispensing pumps.

Water is the primary cause of diesel bug as it creates an environment where microorganisms can grow. For that reason, water prevention and removal make up the greatest part of maintenance. Water enters the tank due to condensation from temperature changes and rainwater entering faulty seals. However, water isn’t the only contaminant. Dirt, debris and must also be removed from the tank. To properly maintain your tank you should:

• Establish a fuel maintenance program to detect when water is present.
• Check the tank for water – on a basic level, this can be achieved by using a water finding paste which you apply to a gauge line or rod. The detection of water will make this change colour. For a more comprehensive method, you can use a filtration tank sampler kit which is then sent off to a lab for analysis.
• Remove water and debris from the tank before microorganisms can grow.
• Inspect fill points and gaskets for damage which may permit water to enter the tank.
• Check and replace filter if necessary. This is usually every 3 to 6 months but depends upon the frequency of use.

Fuel cleaning
There are numerous fuel additives on the market which work to clean the fuel and prevent contamination. Fungicides and biocides prevent the growth of fungus and bacteria which keeps the tank clean and ultimately extends the life of diesel. Anti-oxidant additives prevent fuel from oxidising which reduces the formation of diesel bug.

As well as using cleaning additives in a tank, the tank itself should be emptied and thoroughly cleaned roughly every 5 years. We recommend using a professional tank cleaning service to reduce the risk of fuel spillages or fuel contamination.

What insurance do I need for a diesel tank?

As well as properly maintaining your diesel tank you should check your premises insurance to ensure it covers you for the full cost of diesel leaks. Many insurance companies won’t cover you for diesel leaks if your tank doesn’t have a bund (i.e. if it’s single skinned) and if the leak was caused by neglect. You should check that any insurance policy cover you for:

1. Expenses for cleaning up diesel on your own property including buildings and land.
2. Third-party liability expenses to cover neighbouring land and property.
3. Environmental investigation and clean-up costs if the oil spills into surface or groundwater.

What should I do if my oil tank leaks?
As discussed in our Environmental and financial implications of bulk fuel storage article, the environmental and financial costs of a fuel spill can be crippling. Just one litre of oil can contaminate one million litres of water and oil spilt into the foundations of a building can lead to major renovation work.

Diesel can be spilt for various reasons including cracks, splits, over-fueling, theft and human error. To reduce any impact to the environment that oil spills have it’s important you keep a spill kit near the tank containing commercial sorbent products, sand and earth. The appropriate members of staff should be trained to take immediate action and soak up the spilt oil with the contents of the spill kit. If the spill is likely to reach waterways then you should report the environmental incident on the 24-hour emergency hotline 0800 80 70 60.

How do I prevent diesel fuel theft?

With diesel fuel tanks storing anything from 1,000 to 200,000 litres, and with fuel prices so high, it’s no wonder that diesel tanks are a target for crime. This is a real problem in the UK and in 2018 there were over 25,000 confirmed fuel thefts leading to losses over £1.75m.

Even if your fuel tank is hidden from site you still present a target as criminals follow fuel supplier tankers, and reportedly even using Google Maps Satellite, to locate fuel. That’s why it’s important to be extra vigilant when tanks have just been filled as this presents an ideal time to steal fuel.

The best way to stop theft is to prevent thieves from even trying to steal from your tank. These visual deterrents increase the risk to the intruder while alerting them that they’re dealing with a security-conscious tank owner. This is often enough to make intruders pick an easier target.

Preventing diesel fuel theft

CCTV cameras are probably the most effective way to deter would-be thieves from stealing fuel. Of course, the footage also gives police the chance of identifying and catching the criminal.

You might be surprised how cheap CCTV is now with 4 cameras including night vision, DVR recorder and a mobile app selling for less than £150. You can also get very realistic looking ‘dummy cameras’ for just over £6, giving you the deterrent but not the footage.

Perimeter alarms
Perimeter alarms alert you to trespassers on your land. Simple systems have a short-range and sound when an infra-red beam is broken. At the high-tech end of the scale, you can be alerted to any motion in a large area and even receive alerts via your mobile so you don’t even have to be in on your premises.

Security lighting
Darkness works to the criminal’s advantage, making it much easier to take what they want without being detected. Security lighting is a great deterrent as it increases the chance of getting caught, decreases the intruders feeling of safety, and suggests that the premises owner is security-alert.

Security lighting can either automatically activate when it gets dark, or work by motion detection, and is available from around £20.

The environment
When installing your tank, you should do so with security in mind. Obviously siting tanks within secure areas with protective barriers such as fences and walls makes it harder to see and access tanks. A tip from Farmers Weekly also suggests siting the tank next to a prickly hedge – or planting the hedge next to the tank – to use nature to your advantage. This has the added bonus of helping the police to identify intruders from traces of blood or clothing left on the prickles.

Protecting your diesel tank

As well as simply preventing diesel theft you can physically protect your tank or become alerted to when theft is occurring. If you haven’t yet bought your tank then you should also consider how much protection each tank offers.

Lockable lid, cabinet or roller-shutter door
Some diesel tanks (including our bunded range) are equipped with a lockable lid which can be fitted with a padlock. This gives the fill points protection from siphoning. We recommend using round-shackle padlocks as they leave little room for bolt cutters to grip and break the lock. Also, shackle padlocks are not spring-loaded so they will not unlock if the key barrel is drilled into.

Lockable fill points
One of the easiest ways to steal fuel is simply to siphon it from a fill point or inspection hole in the tank. If these points are exposed, then tank arms (which act like a steering wheel lock) and security locks can be used to offer extra protection to these vulnerable points.

Tank alarms
A tank alarm such as a Watchman Alarm is used to alert you when there is a sudden drop in oil in your diesel tank. A leak in your tank or someone stealing fuel will trigger an alarm to the monitor or mobile device.

Steel tanks
Unsurprisingly steel is more difficult to penetrate than plastic and drilling into a steel tank is noisier and more time-consuming than accessing a plastic tank. There have even been reports of thieves heating metal rods to melt holes into plastic tanks.

Preventing theft and physically protecting your tank does not have to cost a fortune and in the very least it is worth purchasing basic equipment to keep your fuel safe.


We hope that you found this guide useful but if you still require further advice or a quotation please submit an enquiry or give us a call on 01889 567700.