Heating Oil Tank FAQs

Image of Carbery and Harlequin Oil Tanks on Orange BackgroundAs a leading supplier of Heating Oil Tanks, we’re often asked questions about how to store oil safely, securely and responsibly. We’ve provided answers to those questions we’re asked most frequently below. If however, you’ve a question that isn’t answered here, why not get in touch? You can call us in the UK, Channel Islands and Isle of Man on 01789 632 151, on 01 5268 642 in the Republic of Ireland or e-mail hello@fueltank.store.

How far away from the house does an Oil Tank have to be?

The risk of a Heating Oil Tank catching fire is negligible. However, minimum separation distances do exist, to help protect against the risk of a fire originating in a building or adjacent structure, spreading to a tank. Click here to for further guidance and information. 

Do Oil Tanks need planning permission?

Planning permission is not required when installing a Domestic Heating Oil Tank at most homes. Oil tanks at single family, residential dwellings, fall within the scope of permitted development - and therefore planning permission is not usually required - unless the tank:

  • Has an installed capacity greater than 3,500 litres;
  • Will be positioned forward of the principal elevation fronting a highway;
  • Is greater than 3m tall, or greater than 2.5m tall when positioned within 2 metres of a bounday;
  • Will be installed within the curtilage of a listed building;
  • Is positioned on designated land e.g. The Broads, Areas of Outstanding Natural Beauty (AONB), conservation areas and World Heritage Sites;
  • Supplies a flat, maisonette, apartment or other dwelling which is not deemed to be a 'house';
  • Supplies a converted house or a house created through the permitted development right to change use 

If any othe above issues arise, then we recommend consulting with your local planning authority and a competent, professional, oil storage tank technician e.g. an OFTEC Registered Technician. At non-domestic installations, additional factors must be considered and we recommend taking guidance from an OFTEC Registered Technician, or simiarly competent person. 

What size of Oil Tank do I need?

The size of tank you require will vary according to a number of factors. For more information, click or tap here.

What is a Single Skin Heating Oil Tank?

A Single Skin Tank is a large, hollow container, purpose designed for the storage of Heating Oil. Unlike Bunded Tanks or Double Skin Tanks, Single Skin Tanks do not incorporate any form of protection against spills. So, if the worst happens and a spill occurs, an environmental pollution incident will result.

What is a Bunded Oil Tank?

A Bunded Tank consists of two separate tanks - an inner tank and an outer tank. The outer tank can contain 110% of the volume of the inner tank. The inner tank is used to store fuel oil, whilst the outer tank acts as a failsafe in the event of a spill. Should a spill occur, spilt fuel will be contained within the outer tank and an environmental pollution incident will be avoided. Bunded Tanks are a legal requirement at almost all Heating Oil storage installations today in the UK, Republic of Ireland, Channel Islands and Isle of Man. 

What is a Double-Skinned Oil Tank?

Like a Bunded Tank, a Double Skinned Tank comprises of a tank within a tank. The inner tank is the primary storage vessel, whilst the outer acts as a failsafe in event of a spill. However, unlike Bunded Tanks the outer skin of a Double Skin Tank does not necessarily hold 110% of the capacity of the inner tank.

Double Skin Tanks are not suitable at aboveground installations where a Bunded Tank is required. However, purpose-designed Double Skinned Underground Tanks are frequently found - and recommended - at below ground oil storage installations.

How can I tell if I need a Bunded Tank?

If you’re installing an Aboveground Heating Oil Tank with a capacity of 200 litres or more, at agricultural, commercial, industrial or institutional premises, a Bunded Tank is required. The only exception is where total on-site storage capacity is less than 200 litres and / or, at installations where the tank is installed below ground.  

At most Aboveground Domestic Heating Oil storage installations, a Bunded Tank will also be required. Click here to find out more about Home Heating Oil storage requirements.

Are Single Skin Oil Tanks illegal? 

No. However, Single Skin Oil Tanks should only be installed within a suitably bunded area, or at installations where a spill would not result in an environmental pollution incident. Click here for further guidance. 

What materials are Heating Oil Tanks manufactured from?

  • Plastic Oil Tanks are manufactured from an EN 13341 approved grade of Medium Density Polyethylene (MDPE), consistent with OFTEC's OFS T 100 standard; 
  • Steel Oil Tanks are manufactured from mild steel, consistent with the requirements of British Standard BS 5410 and OFTEC’s OFS T 200 standards.
  • Aboveground Hybrid Tanks typically comprise a Mild Steel outer tank and an inner tank manufactured from Medium Density Polyethylene.
  • Underground Hybrid Tanks usually comprise an other tank manufactured from Glass Reinforced Polyester (GRP) and an inner tank manufactured from Medium Density Polyethylene.

How often should I have my Heating Oil Tank inspected and serviced?

All Heating Oil Tanks should be inspected and serviced at least annually. The inspection and service should be recorded. Failure to comply with this requirement may void the balance of any warranty remaining on the tank. Many Boiler Service Engineers will routinely service and inspect your tank, during your annual boiler service - but it's always a good idea to ensure the service also includes your tank.

Storage tank inspection, service and maintenance activities should only be completed by a professional, competent, service engineer, such as a Technician registered with The Oil Firing Technical Association (OFTEC). To find a local service engineer, click here to visit the OFTEC website.

I’ve found water in my Heating Oil. Where has this come from?

Small quantities of water will accumulate inside almost any Heating Oil Tank due to the natural temperature cycle. As the tank warms up during the day and cools down at night, condensation will form naturally inside. Additionally, condensation will also gather in between the inner and outer tanks on Bunded Tanks.

Any water present inside a tank should be removed and disposed of responsibly as part of your tank’s annual service. Failure to periodically inspect and remove water from any Heating Oil Tank may interfere with the operation of any combustion appliance connected to it and may additionally cause irreperable damage to your tank. 

On warm days I can smell Heating Oil odours coming from my tank. Does this mean I have a leak?

In the absence of any other symptom of a spill, almost certainly not. All Heating Oil Tanks are fitted with vents, to prevent the tank becoming pressurised and continually vent to atmosphere. The smell is simply more noticeable on warmer days.

How do I remove Sludge and Contaminants from my Heating Oil Tank?

An inspection aperture is now fitted to most tanks, usually beside, or combined with a tank’s fill point. It allows the tank not only to be inspected, but permits sludge and contaminants to be pumped from the tank and disposed of responsibly too.

How long will an Oil Tank last?

It simply isn't possible to predict how long a tank will last before replacement is required. However, for guidance, we would suggest a maximum operating life of:

  • 10-years for Single Skin Oil Tanks;
  • 20-years for Bunded Oil Tanks;
  • 10-years for Underground Tanks. 

What is the Best Oil Tank to buy?

The best oil tank to buy, will depend upon your own individual circumstances, including where you live, the thermal efficiency of your home, farm or business and of course your lifestyle. As a responsible storage tank supplier, we  always recommend that all Heating Oil Tanks should be bunded and fully comply with industry standards, together with all applicable fuel storage regulations. 

To help you choose the perfect heating oil tank, we've written our very Heating Oil Tank Buyers' Guide. It's free of gobbledygook and explains key considerations for anyone considering a new tank. Click or tap here to download your own personal copy

Can I bury an Aboveground Heating Oil Tank in my garden?

A very definite no. Installing an aboveground tank below ground will result in premature product failure and an environmental pollution incident. 

When should I consider replacing my Heating Oil Tank?

There is no universally agreed timescale for the replacement of existing Heating Oil Tanks. However, we would recommend that serious consideration is given to the replacement of:

  • Any Single Skin Tanks older than 10 years;
  • Any Bunded or Double Skin Tank older than 20 years.

There’s a 2-pin socket on top of my Heating Oil Tank. What’s it for?

This allows fuel delivery personnel to connect overfill prevention equipment to your tank during refueling. This device serves no other purpose and is not an electrical connection.

Can I install a Heating Oil Tank inside my home or garage?

Yes, in theory you can - but it's rarely something we would usually recommend. Any such tank must be:

  • Installed within a 1-hour, fire-resistant chamber;
  • Incorporate adequate secondary containment i.e. bunding; 
  • Be positioned at the lowest point in the property;
  • Capable of being refueled safely. 

Put simply, any such installation is unlikely to prove simple or straightforward. Additionally, some storage tank manufacturers do not permit their products to be installed internally. So, before progressing any internal installation, we would recommend you first consult with a professional, competent, storage tank installer, registered with The Oil Firing Technical Association (OFTEC) in the UK, Republic of Ireland, Channel Islands and Isle of Man. To find a local storage tank installer, click here to visit the OFTEC website.

Can I use a Heating Oil Tank to store fuel for my AGA, Alpha, Esse, Firebird, Marshall, Rayburn or other oil-fired range cooker?


What fuels can I store inside a Heating Oil Tank?

When connected to a fixed combustion appliance (e.g. Boiler, Cooker, Grain Dryer, Warm Air Heater etc.), all Heating Oil Tanks supplied by us are suitable for the storage of Agricultural Fuel Oil, Diesel, Gas Oil, Kerosene - excluding Jet A1 and all other aviation fuels. Heating Oil Tanks are also not suitable for the storage of Liquefied Petroleum Gas (LPG), Petroleum Spirit (Petrol) or any other highly flammable liquid.

If you’re considering the purchase of a Heating Oil Tank for any fuel not listed, please contact us prior to purchase. You can call us on 01789 632 151 in the UK, Channel Islands and Isle of Man, on 01 5268 642 in the Republic of Ireland or e-mail hello@fueltank.store. We’re open 9am - 5pm weekdays - excluding Bank and Public Holidays.

Can I store Liquefied Petroleum Gas (LPG) in a Heating Oil Tank?


Can I store Hydrotreated Vegetable Oil (HVO) in an existing Heating Oil Tank?

Research completed by The Oil Firing Technical Association (OFTEC) and The UK & Ireland Fuel Distributors' Association (UKIFDA), suggests HVO can be stored in an existing heating oil tank. However, it is recommended any residual kerosene is drained from the tank and disposed of responsibly and the tank is throroughly cleansed, prior to being refueled with HVO. Additionally, the oil line and all equipment connected to it should be assessed for compatibilty with HVO. 

How close to an adjacent structure can I place a Heating Oil Tank?

Click here to view detailed guidance on minimum clearance distances.

How close to a boundary can I position a Heating Oil Tank?

Click here to view detailed guidance on minimum clearance distances.

How close to a flue can I install a Heating Oil Tank?

Click here to view detailed guidance on minimum clearance distances.

How close to a Liqufied Petroleum Gas (LPG) installation can I site a Heating Oil Tank?

Click here to view detailed guidance on minimum clearance distances.

What is the 

Are your Plastic Heating Oil Tanks compliant with EN 13341?

Yes, where applicable, all our Heating Oil Tanks have been independently tested to ensure compliance with the requirements of British Stanard BS EN 13341 and Irish Standard IS EN 13341 - a legal requirement for all Plastic Heating Oil Tanks sold in the UK and Republic of Ireland today. Declarations of Performance can be downloaded from each product page or requested by e-mail to hello@fueltank.store

Following the withdrawal of the United Kingdom from the European Union in January 2020, does British Standard BS EN 13341 remain a relevant standard in the UK?

Yes, all Plastic Heating Oil Tanks supplied, sold, distributed or installed in the United Kingdom must be compliant with British Standard BS EN 13341. 

Are your Plastic Heating Oil Tanks compliant with OFTEC’s OFS T 100 Standard?

Yes, where applicable, all our Plastic Heating Oil Tanks have been independently tested in accordance with OFTEC’s OFS T 100 Standard and are OFCERT Licensed. OFCERT License Numbers can be verified by cross referencing with OFTEC’s Online Equipment Directory. Click here to visit the OFTEC website.

Can I fit a Gravity Fed Diesel Delivery Hose to a Heating Oil Tank?

No, and as a responsible supplier, we do not supply Gravity Hose Kits. Connecting a Gravity Hose Kit to a standard Heating Oil Tanks will:

  • Invalidate any warranty supplied with the tank, since it is being used for a purpose for which it was not intended i.e. the dispensing of Diesel fuel;

  • Almost certainly contravene environmental and possibly safety regulations in most jurisdictions;

  • Prove ineffectual, since the internal diameter of most Heating Oil Tank outlets ranges from 10mm to 0.5" (c.12.5mm) and too narrow for the effective transfer of Diesel fuel;

  • Need to be raised a significant distance from ground level, resulting in a product which may be deemed unsafe to fill.

If you have a requirement to store and dispense Diesel fuel, we would instead recommend a purpose-designed Diesel Storage and Dispensing tank. These are a competitively priced, environmentally responsible and practical alternative to old-fashioned gravity-fed Diesel delivery systems. Click here to view our range of Bunded Diesel Storage and Dispensing Tanks.

What is an Interstitial Leak Detection System?

Often fitted to Double Skin Underground Tanks, an Interstitial Leak Detection System activates an alarm in the event it detects liquid between the inner and outer tanks. 

What is a Bund Warning Alarm?

A Bund Warning Alarm allows the bunded area (i.e. the space between the inner and outer tank) to be checked for the presence of liquid. Bund Warning Alarms can take the form of either a stand alone device or can be integrated into a tank's contents gauge. It's recommended that Bund Warning Alarms are fitted to tanks, where it's impractical to visually check the bunded area for the presence of spilt or surplus fuel. 

If I purchase a Second Hand / Used Oil Tank and install it on my premises, will I benefit from any remaining warranty?
I have found a crack in my Heating Oil Tank, but it's not leaking. What should I do?

You should make arrangement to have your tank inspected by an OFTEC Registered Technician, or similarly competent person, without delay. 

Do all your Heating Oil Tanks come with an Oil Tank Gauge as standard?

Carbery Plus Single Skin Heating Oil Tanks, Carbery Ultra Bunded Oil Tanks, Harlequin ITE Series Bottom Outlet Bunded Tanks and ITT Series Top Outlet Bunded Tanks come complete with an Oil Tank Contents Gauge as standard. All other Heating Oil Tanks can be supplied with a contents gauge - just specify when placing your order. 

Where are Harlequin Oil Tanks made?

All Harlequin Oil Tanks are manufactured in the UK. Harlequin has 2 manufacturing facilities, in Moira, Northern Ireland and in East Kirkby, Lincolnshire.

Where are Carbery Oil Tanks made?

All Carbery Oil Tanks are manufactured in Clonakilty, West Cork in the Republic of Ireland. 

Where can I obtain a replacement Oil Care label?

If you live in the UK, these can be ordered from the Environment Agency. To order, click or tap: http://oilcare.org.uk/dealing-with-spills/stickers/ If you live outside the UK, contact your storage tank manufacturer. 

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