How Do I Check my Heating Oil Level? A Guide to Avoiding Unnecessary Excess Costs

July 30, 2020
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Keeping an eye on your heating oil levels is one of those dull domestic admin chores that needs to be done, but can often slip the mind!

Running out of domestic heating oil might catch you in a bit of a spin requiring a panicked call to your supplier with potential additional costs. More importantly, running your heating oil completely dry can cause costly damage to your boiler and might require a maintenance call out too.

To avoid this situation we’ve pulled together a simple guide to keeping on top of how much heating oil is in your tank.

Related contentA Simple Guide to Taking Care of Your Oil Heating System

Methods to check your heating oil level

If you have recently moved into a property that uses domestic heating oil, you might be unsure as to how to check your fuel level. There are four main ways to check your oil level;

Related content – Buying a New Home – The Advantages and Disadvantages of Heating Oil


Using a dipstick is a traditional, manual method of measuring the oil content in your fuel tank. It is recommended that a straight measuring stick is used. It is then dipped into the tank, and shows the level of oil in the tank, in the same way you would use the engine oil dipstick on your car. This is becoming less and less common, but is always a reliable fall back if a gauge isn’t present.

Sight Gauge

Most fuel storage tanks are fitted with a clear plastic tube on the side. This tube is known as a sight gauge or is sometimes called a water gauge. The level of oil in the tank is visible through the clear plastic tube. This method is not always accurate as overtime the tube may become discoloured making it hard to accurately read the oil level.

Float Gauge

They have a float that goes up and down with the oil level. The gauge sits on top of the tank and is connected to the float with a string. The string is wound around the mechanism in the gauge that will turn the dial depending on the level of the oil. They will usually measure the level in “empty” – “1/4 full” – “1/2 full” – “3/4 full” -”full”

Digital Monitoring System

A digital monitoring system remotely monitors your fuel level and sends this information to a receiver device within your home. There’s a few different options available, some devices have an alarm system that sounds when there is a dramatic drop in fuel ( alerting you to fuel theft or a leak).

When to fill up your heating oil fuel tank

You don’t want to let your heating oil level get too low. If you have an older tank there will be sediment and impurities settled at the bottom, if the oil level is low, this sediment will get carried through your fuel line and cause problems to your boiler.

The level when you should refill your oil tank, firstly depends on the size of your oil tank, most common domestic sizes range from 1000 to 2500 litres.

It is a safe option to get your tank refilled when it is at a quarter full, that way there is no chance of you running out of heating oil while you are waiting on a delivery and will prevent impurities running through your system.

Three tips so that you don’t get caught short:

Tip 1 – Set a regular day to check your heating oil level

It is a good idea to set a regular day to check your fuel tank oil level. You can pop a reminder on your phone calendar or if you prefer to mark a specific day on your calendar – this will help you get in a routine. In the summer months, when you are not using your heating system, you should check your levels every 6 weeks. When your usage increases during the colder months, you should check your levels once a fortnight.

If you are techy and someone that keeps organised using your mobile, you might be interested in a monitor that works through your device. The Watchman Anywhere & the Watchman Anywhere Pro checks your oil levels and sends the information through a data centre to display on your personal online dashboard.

This technology gives you the ability to track your own or your loved one’s tanks whether you are in this country or abroad. Ideal if you have a rental property or work away a lot.

Tip 2 – Check your heating oil fuel gauge is in working order

If your fuel gauge has not moved the last few times you have checked it and you know you have had your heating on, there is a chance the gauge might be faulty.

To check the oil tank gauge is working on a float gauge, unscrew the plastic dome covering and gently nudge the rod downward, then let go. If it’s working, it’ll spring back up to the same level as it was before you pressed it down (assuming your tank isn’t empty).

If you think that your digital gauge is faulty, you can check your fuel tank level using the dipstick method mentioned earlier. Open the fill valve cap on the top of the tank. Insert the dipstick until it reaches the bottom of the tank. Using a pencil or pen, mark on the dipstick where the top of the fill valve is. Remove the dipstick and hold it against the side of the tank. The wet mark shows how high the oil is, then you can see if this matches what your digital gauge is reading.

Tip 3 – If you need to push the reset button – You could be low on heating oil

Your boiler should fire automatically. If you need to press the button every day or multiple times a day, then it is likely that you are running out of oil.

If you have recently moved into a home that is heated by a boiler that uses domestic heating oil, then you may not be very familiar with the way the heating system works. If you are having to constantly reset the boiler it is a sign your oil is low and you need to schedule a heating oil delivery

Related content What type of oil do I need?

Tip 4 – Loud noises from your boiler, could signal you’re low in oil

If you are running out of home heating oil, then you may hear a series of bangs or a much louder roar as the boiler starts. These noises often occur due to the air that is pulled into the fuel line. This air can enter the oil line as fuel levels drop substantially, and this can cause the flame to burn inconsistently. The roaring or banging sounds that you hear occur as the flame builds in strength and forces pressure against the sides of the heater.


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