If you are a household which uses a heating oil tank, you need to be fully aware of the issue of water contamination. It’s also good to know how to identify it, what most commonly causes it and what you can do to minimise the impact of this problem.
What causes water contamination in heating oil tanks?
- In periods of fluctuating temperatures, moisture in the air condenses on your tank’s inner walls, which are cool. This is the most common cause behind water contamination as warm, moist air enters the tank and cools, forming water droplets. It’s something to look out for, particularly in partially full tanks.
- Equally, if filler caps aren’t sealed properly or you have a damaged lid on your tank, or it has cracks or holes, or a faulty seal, rainwater can get in. With underground tanks, if there are cracks or breaches in them, groundwater can seep through them.
Additionally, external flooding sometimes forces water through gaps in the tank.
Why should water contamination be avoided?
Unfortunately, water contamination in heating oil tanks can lead to a number of severe headaches, including:
- Freezing: In icy conditions, liquid in fuel lines may freeze, cutting off the flow of oil and preventing your heating system from working.
- System failure: Water contamination often leads to poor burner performance, injector issues and, ultimately, potential total system shutdown.
- Rust and corrosion: Water leads to rust (or iron oxide) on tanks built from metal, weakening the structure and causing abrasive particles which harm tank components.
- Build-up of sludge: Rust, oil and bacteria combine in a sludge at the bottom of the tank, where it clogs up filters and nozzles.
- Growth of microbes: Bacteria naturally flourish in water, generating corrosive acids plus a thick sludge which blocks fuel filters and lines.
How can you tell if water has contaminated your oil tank?
Whatever the cause of the contamination, the reality is that it can be hard to detect from an external inspection, because water that gets into your tank will just sink to the bottom, making it difficult to spot and remove.
Indeed, the first indication you may have that something is wrong is when your heating isn’t working properly. So frankly the best option is to get your heating engineer to point out any issues for you on every service.
But if you want to do this yourself in between times, you can buy some water-finding paste online and use it with a long stick such as a garden cane or anything else that reaches to the very bottom of your tank.
Smear the paste on the end of the cane and push it into the tank until you reach its base. The instructions will tell you how long to wait before you can pull it out. You will know you have contamination if the colour of the paste has changed.
Dealing with water contamination
Clearly, you’ll need to get rid of the contaminating water as soon as you find it, before it infiltrates your boiler and results in real damage.
Metal tanks typically come with a sludge valve at the base of the tank, which you can use to let water drain away. With plastic tanks, you need to ‘lift’ the water out, and, depending on how much liquid is there, you could try a water-absorbent tank sponge for small amounts of fluid. Alternatively, you could try pumping the water away.
Ultimately, the best thing to do in this situation is to contact a specialist. An OFTEC-registered engineer is your best bet, since you might also need to flush out your boiler feeder pipe and change the fuel filters after the water has been taken away.
A professional can drain off water safely, frequently via a fuel pipe which they will set up at the bottom of the tank.
Reducing the risks of contamination
While it may not be possible to prevent condensation completely, you can monitor water levels in your tank. Here are some other tips:
- Have an annual oil tank inspection from an OFTEC-registered engineer.
- Check your oil tanks aren’t showing any signs of corrosion, cracks, oil staining or any other type of physical damage.
- Inspect the area around your tank for any indications of leaks.
- Take action if you have a bulging tank, since this can mean you have weak points in the exterior walls.
- Be sure that caps and lids are properly fastened.
- If you have a bunded tank, ensure the bund isn’t full of water or oil and get rid of any garden waste such as leaves. The bund also, obviously, needs to be in a decent condition and able to contain any potential oil spillages.
- If you have overhanging trees or foliage, cut these back since they will keep dripping on to your tank even after it has stopped raining.
- Older tanks (i.e. those more than 15 or 20 years old) may need replacing. If this applies to your model, take appropriate action.
Finally, you could also use approved water-absorbing additives to deal with less severe water contamination.
The key thing to remember is not to ignore this issue, and to bear in mind the potentially significant headaches you’ll face if you don’t deal with water contamination as quickly as possible.
Get in touch with an oil tank expert immediately for an assessment of the health of your tank, and for rapid disposal of the contaminating liquid.
Make LV Fuel Services your first port of call
We offer cost-effective, reliable and efficient oil tank services across the UK for business and domestic customers. Get in touch whether you need oil tank cleaning, fuel tank maintenance or tank installation or replacement.
With many years’ industry experience to our name, we have all relevant industry accreditations, and always make safety and environmental concerns a priority.
We’ll also always be happy to answer any questions you may have. Call 0800 799 9739 or email info@lvfuelservices.co.uk or request a quote.
