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UK Heating Oil Tank Regulations: Is Your Tank Legal?

OilCompare Team
January 2026

Is Your Oil Tank Legal?

If you are replacing your oil tank or installing a new one, you must comply with current building regulations. Even for existing tanks, if yours is deemed a substantial environmental risk, an engineer may refuse to fill it.

Regulations vary slightly between England, Wales, Scotland, and Northern Ireland, but the core safety principles (based on OFTEC standards) are similar.

1. Bunding: The Big Rule

The most significant requirement is bunding. A "bunded" tank is essentially a tank within a tank. If the inner tank leaks, the outer shell catches the oil, preventing it from soaking into the ground.

You MUST have a bunded tank if:

  • You live in Wales (all new installations).
  • The tank capacity is over 2,500 litres.
  • The tank is within 10m of "controlled water" (stream, river, ditch, septic tank).
  • The tank is within 50m of a borehole or spring.
  • The tank is over hard ground (concrete/tarmac) where a spill could run into a drain.
  • The vent pipe is not visible from the fill point.

Reality Check: Almost all domestic properties in the UK fall into one of these categories. Single skin tanks are rarely legal for new domestic installations anymore.

2. Location & Fire Protection

Oil is flammable. You need to ensure a fire in your house or garden doesn't spread to the tank (and vice versa).

Separation Distances:

  • 1.8m away from non-fire rated buildings (sheds, gazebos).
  • 1.8m away from openings in your house (windows, doors) unless a fire barrier is installed.
  • 1.8m away from the boiler flue terminals.
  • 760mm away from non-fire rated boundaries (wooden fences).

If you can't meet these distances, you can install a fire barrier (a masonry wall or special fire-rated panel) between the tank and the hazard.

3. The Base Support

A full 1,000-litre tank weighs over a tonne. It needs a solid foundation.

  • Material: Concrete, paving stones, or stonework.
  • Thickness: At least 100mm thick.
  • Size: The base must extend 300mm beyond the edge of the tank on all sides.
  • Stability: It must be level and incapable of slipping. Placing a tank directly on soil or grass is not allowed.

4. Annual Inspections

While not a "law" for homeowners in the same way as gas safety certs, you have a "duty of care" to the environment.

  • If your tank leaks and pollutes a local stream, YOU are liable for the cleanup costs, which can run into tens of thousands of pounds.
  • Most home insurance policies require you to maintain the tank. If it leaks because it was rotten and uninspected, they may refuse to pay out.

Summary Checklist

Does your tank installation pass?

✅ Bunded (Double-skinned)

✅ On a solid, level concrete base extending 300mm around it

✅ 1.8m away from windows/doors (or has a fire wall)

✅ 760mm away from wooden fences

✅ Accessible for the delivery driver

If you are unsure, ask an OFTEC technician to perform a "tank health check" during your next boiler service. It's better to be safe than facing a massive environmental cleanup bill.

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