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Home & garden.

Updated: 19 Oct 2021

Heating oil tanks

Find out about different types of heating oil tanks, prices and sizes. Plus how to maintain your oil tank and protect yourself against oil theft
Sarah Ingrams
Heating oil tank 451066

Heating oil tanks are made from fabricated steel or plastic and can be installed inside, outside or underground. 

Keeping your tank and system well maintained will keep them as efficient as possible, which helps to keep your costs down and reduce the risk of breakdown.

The oil in your tank is valuable, so it’s also important to protect it from theft as best you can.

If you're thinking of updating your heating system, see our oil boiler reviews to find out which have been rated the most reliable by customers and heating engineers.

Heating oil tanks: the essentials

Heating oil tanks can be single-skinned, double-skinned (where the tank has two layers) or integrally bunded (a bund is a protective layer).

Integrally bunded tanks have one tank sitting within another. The outside tank houses the main tank's fittings and vents (see image gallery below). These tanks give better protection than double-skinned tanks, as there is more room between the two layers to prevent oil leaking externally.

Heating oil tanks

A large collection of images displayed on this page are available at https://www.which.co.uk/reviews/heating-oil/article/heating-oil/heating-oil-tanks-aLhAn5h5u4dA

Most single and double-skinned tanks need to have a bund built around them for protection, although this will depend on where you live and the position of your tank. The bund can hold 110% of the tank's contents.

Your tank should be at least 1.8 metres away from doors and windows and on a thick, sturdy base.

Heating oil tanks should last around 20 years. If yours is nearing the end of its life, it's worth replacing it to avoid any leaks. 

Where can I buy a heating oil tank?

Heating oil tanks are available online and through local, independent companies. 

Before you buy a tank, check that it's manufactured to Oftec standards. An Oftec-registered technician can help you choose the type of tank and where to put it so that it complies with location regulations (to limit environmental and fire risks) and building regulations, both of which vary across the UK.

Use the Oftec website to find one in your area, or contact the Environment Agency for further advice.

Heating oil tank prices

Prices generally range from around £500 for a small single-skinned tank to more than £2,000 for a large integrally bunded one. 

Price also depends on size, which can vary from around 1,000 to more than 3,500 litres (although these tend to be used commercially).

How much heating should I order?

Heating oil delivery truck

1,000 litres could last up to a year, but it depends on a number of factors, such as:

  • the size of your house
  • how much you have your heating on
  • whether your oil boiler is efficient.

Try to work out how much you're using by keeping tabs on your tank gauge over time. 

All heating oil tanks should have a gauge to indicate how much oil is left in the tank. This may be on the tank, next to it, or displayed remotely. 

If your tank doesn't have one, you can buy one separately. They cost from £25 for a basic gauge, to more than £80 for a digital remote one. 

Keep an eye on your oil tank gauge so your supply doesn't get too low. Make sure you order more oil before it becomes less than a quarter full, especially in winter. 

You should only fill your tank to around 80-90% of its capacity, to avoid spillages. 

Don't pay more than you have to for heating oil. Read our expert advice on how to get the best price for heating oil.

How often should my heating oil tank be serviced?

Get your tank serviced annually to ensure it's in good working order. Some manufacturers recommend six-monthly checks. You should get an Oftec-registered technician to do the service.

Inspections cost around £70 to £100. A service should check:

  • pipework
  • integral bund
  • gauges
  • valves
  • oil filters.

If you've moved into a new property and ‘inherited’ your heating oil tank, it's worth arranging an inspection as soon as possible.

Steel tanks have an oil-resistant coating, which needs to be maintained to prolong the life of the tank. Check with the manufacturer to find out what maintenance is needed besides annual servicing. 

You should also have your oil boiler serviced annually. Find a trusted local engineer using Which? Trusted Traders.

Heating oil tank checks you can do yourself

Besides an annual service, there are simple checks and precautions you should take to make sure your tank is in a good condition:

  • Check for damage, such as bulges, deep scratches, cracks, discolouration, rust or major dents.
  • Look out for any oil that has leaked out, particularly around pipes, valves and seams.
  • Make sure that any external protection, such as a bund (scroll up to find out more), isn't filled with water, oil, rubbish or weeds.
  • Keep access to and around the tank clear.
  • Make sure vents, gauges and access points are closed and protected so that rainwater, insects or dirt can't get in.
  • Check that gauges and alarms are working correctly, including their batteries. Consult the manufacturer for advice on how to do this.
  • Keep an oil-spill kit with drain blockers, leak-sealing putty and absorbent materials.
  • Make sure your tank is only filled to around 80-90% of its capacity and ensure your tank has an overfill protection device or alarm.

What to do if your heating oil tank leaks

Oil is toxic and harmful to the environment, including animals, plants and water sources. 

It you spot a leak, put a bucket under it straight away. Defects should be fixed immediately by a professional.

It's against the law to cause pollution, so you should call the National Pollution Incident hotline on 0800 80 70 60 (England, Scotland and Northern Ireland) or 0300 065 3000 (Wales). 

It can cost thousands to clean up an oil spill, so check that your insurance:

  • has a high enough liability limit to cover the cost of cleaning up your property or neighbouring land
  • covers the cost of replacing lost, leaked or stolen oil
  • covers environmental clean-up for accidental loss.

Not all insurance policies cover oil leakage. See our guide to home insurance for more information, and to find which insurance companies are highly rated by its customers.

Heating oil tank problems: sludge, water and cold weather

If sludge or water get into your tank, they can clog up the pipework, damage your heating system and reduce the efficiency of the oil. 

Water might get in if it’s raining when your oil is delivered, or from condensation. Sludge tends to build up in tanks where oil has been stored for a long time.

Look for signs of a darkened area at the bottom of the tank. This can be caused by erosion due to sludge. You can also buy water-finding paste, which changes colour to indicate whether water is present. 

A technician can remove water and sludge and clean your tank, as well as fix whatever's causing the problem.

Heating oil doesn't freeze into a solid lump. However, in very cold weather (usually -39°C), heating oil can ‘wax up’. This means it forms crystals that stop it from flowing as easily. 

Kerosene is less likely to become waxy than gas oil, but you can buy additives to help prevent crystals forming. These cost around £15 per 1,000 litres of oil.

Heating oil theft

Heating oil is pricey, so it can be attractive to thieves. Adding locks or lockable valves will help to prevent theft, and in some cases they're a legal requirement. Your engineer or supplier can advise you on this.

Shield your tank so it isn't visible from the road. But make sure its position still complies with guidelines and access to it isn't restricted. Ask an Oftec-registered technician for details.

You could also install motion-sensitive security lighting to alert you if there's a problem, or an alarm (costing around £80) that will react if the oil level drops suddenly – which is also useful for notifying you of an oil leak.

It's cheaper to order your heating oil in bulk, though this can mean that you have more to lose if it's stolen. Find out more about bulk-buying in getting the best price for your heating oil.

Your rights with heating oil suppliers

Q: The supplier changed the price of my heating oil order before it was delivered. What should I do?

Check the terms and conditions of your purchase. Some specify that the contract isn't formed until the oil is dispatched. 

If the contract allows for the price to be increased after it has been agreed, it should generally give you a right to cancel if the new price is too high.  

Always ask for a written confirmation of your order so you don't get a surprise when you get your bill. Written confirmation should include:

  • the amount of oil you're ordering
  • price
  • delivery timescales.

Ordering over the phone is classed as a distance selling contract. So your supplier must give you certain information, such as the price agreed. Where this isn’t possible, it should show how the price will be calculated, as well as any additional payments.

The 14-day cooling-off period under the Consumer Contracts Regulations distance selling regulation doesn't apply to heating oil. Read more in our guide to the Consumer Contracts Regulations.

Q: The oil delivered is sludgy. What should I do?

If the oil delivered is sludgy and unusable, you have the same consumer rights with most other goods and services covered in law by the Consumer Rights Act. 

Find out how the Consumer Rights Act can help if you're having problems with your heating oil order.