Every transport depot stores oil, even the ones that do not think of themselves that way: the diesel tank, the waste oil from services, the IBC of hydraulic oil, the drums behind the workshop. The oil storage rules that apply to businesses in England and Wales, published by the Environment Agency and Defra, kick in at a threshold almost every depot crosses: an oil storage container with a capacity of 201 litres or more. Get the containment wrong and the consequences are not just environmental - you could be fined or prosecuted, and the Environment Agency can serve an anti-pollution works notice forcing you to bring the store up to legal standards.
The rules apply to any business site - the guidance expressly includes marinas and public sector buildings alongside ordinary commercial premises - holding a container of 201 litres or more. At homes the threshold is 3,501 litres, which rarely matters; for depots, 201 litres is the number.
“Container” covers more than the obvious tank:
And “oil” is defined widely: petrol, diesel, biofuels, kerosene, vegetable oils, hydrotreated vegetable oils (HVO), synthetic lubricating oils, oils used as solvents, biodegradable hydraulic oils, bitumen-based liquids in some forms, cutting fluids and insulating oils. Grease gets a lighter touch - the Agency may ask for it to sit on a drip tray, but expects grease containers to be under 200 litres or stored indoors.
Waste oil. Storing waste vegetable oil, waste cooking oil or waste synthetic oil follows the same rules. Some waste oils - drained engine oil, gearbox oil, hydraulic oil, diesel-petrol misfuel mixtures - are outside these rules but may need an environmental permit instead. “Outside the storage rules” does not mean “unregulated.”
Farms doing haulage. Farms storing agricultural fuel oil have their own requirements, but oil stored on a farm for non-agricultural business purposes - the guidance’s own example is fuelling lorries or trucks - follows the business rules in this guide. A mixed farm-and-haulage yard needs to know which regime each tank sits under.
Exemptions. Containers that are underground, at a refinery, at an onward-distribution depot, or stored in a building - a structure with walls and a roof that would capture a leak - are outside these rules, though indoor storage can trigger Building Regulations fire safety measures instead.
The heart of the regime is secondary containment - the backup that catches what the container loses. Fixed tanks must be bunded; other containers can be bunded or use drip trays.
The capacities are precise:
Bunds can be manufactured as part of the tank system - “integrally bunded” tanks - or built around existing containers, but either way the capacity test is the same.
If you fill a container via a remote fill pipe - a fill point outside the secondary containment, where the tank may not even be visible from where the delivery connects - you must use a drip tray to catch anything spilled during delivery. Bulk diesel deliveries to a depot tank are exactly this scenario, and the drip tray at the fill point is one of the cheapest compliance items in the whole regime.
Oil storage rules are depot infrastructure law: set up once, inspected forever. The 201-litre trigger means nearly every transport yard is in scope, and the 110% bund is the standard the Environment Agency will measure you against.