Your oil tank is a long-term investment. The right size saves money on every order, and correct siting keeps you on the right side of building regulations and protects the environment.
Choosing a size
Domestic tanks typically range from about 1,000 to 2,500 litres. A useful rule of thumb is to choose a tank that holds at least half your annual consumption, so you can order in volumes of 900 litres or more and benefit from lower per-litre prices. Remember that a tank should never be filled to its brim capacity; suppliers fill to a safe working level.
Bunded or single-skin?
A bunded tank is a tank within a tank: the outer skin catches any leak from the inner one. Most new domestic installations use bunded tanks, and they are required in a number of situations — for example where the tank is large, close to a watercourse, drain or borehole, or where a spill could reach a neighbour's property. Rules differ between England, Wales, Scotland and Northern Ireland, so always have a qualified installer carry out a risk assessment.
Where the tank can go
Building regulations in England and Wales set fire-separation distances for oil tanks. As general guidance, a tank should be kept well away from openings in the house such as doors and windows and from flues, and some distance from property boundaries, unless a fire-rated barrier or wall is installed. An installer registered with a competent person scheme such as OFTEC can confirm what applies to your home and self-certify the work.
Checking your tank
- Look for cracks, bulges, rust or white stress marks on plastic tanks.
- Check the base is level, stable and extends beyond the tank footprint.
- Make sure the bund is dry; water or oil inside it needs attention.
- Keep vegetation cut back so you can see all sides of the tank.
Security
Heating oil theft rises when prices are high. Lockable caps, a remote level monitor that alerts you to sudden drops, motion-sensor lighting and screening the tank from the road all help. Check that your home insurance covers oil loss and spill clean-up, which can be very expensive.
When to replace
Plastic tanks often last around 20 years; steel tanks can last longer if maintained, but corrode from the inside. If your tank shows damage or is approaching the end of its life, replace it before it fails — a leak can cost far more to clean up than a new tank.
A larger, well-sited tank also makes it easier to follow our advice on timing your orders.