How to Prevent Rust in Your Air Compressor Tank

When you add water and moisture to metal, you’re always going to be at risk of developing rust. That goes for your air compressor, too! Providing you take good care of your air compressor tank, there are no reasons why rust should ever be an issue for you.

To prevent rust from developing in your air compressor tank, you need to keep it well-drained, as dry as possible, and, where necessary, lubricated and oiled. Prevention of rust is easier than the cure here – you can trust us on that!

In this guide, we’ll dive deeper into how to prevent rust in air compressor tank units – it’s easier than you think.


How does rust develop in an air compressor tank?

Essentially, rust occurs when you allow oxygen, hydrogen and iron to interact. It’s a chemical process. Rust doesn’t always develop right away, or even very quickly – however, over time, condensation is likely to build up in your air compressor tank. This moisture, if not taken care of, is going to produce more and more rust. 

The bottom line is, if you leave an air compressor tank full for long enough, it’s going to get rusty.

Water vapor is a major problem for air compressor tanks as it can so often go unchecked. Just because your air compressor is still performing at its best, and it looks fine from the outside, doesn’t mean it is going to be free from problems internally. It’s always a good idea to check and maintain your inner tank regularly.

Rust levels can and will vary depending on a couple of factors. If you barely use your air compressor and you drain it after each use, it’s unlikely to be a huge problem. The same applies if you live or work in an area that’s particularly dry or arid. Humid areas are likely to breed more moisture, no matter how often you use your air compressor.

Why is it important to prevent rust in your air compressor?

Rust isn’t just unsightly and a pain to have to deal with – it’s extremely dangerous. Rust building up inside your air compressor tank will gradually weaken its integrity. Therefore, the weaker your tank gets, the more chance it has of breaking down.

At worst, your air compressor tank could explode if the walls become rusty and weak enough. Therefore, you need to take steps to prevent this scenario from ever occurring.

In some cases, people prescribe actually taking care of the rust head-on. In our experience, however – and this goes for small air compressors and larger units alike – preventing rust should be the first priority.

Should I remove the rust myself?

No. Let’s be clear on this – leave any existing rust on the inside of your tank well alone!

You’re probably likely to see rust and will want to get rid of it. We’re with you – it’s really nasty stuff, and it won’t do your tank any good. However, while you might be tempted to start sanding the rust away, it’s never a good idea.

That’s because when you start attacking the rust yourself, you’ll actually be attacking the tank walls. The aim is to stop your tank from corroding – and by getting in there and scraping away at it yourself, you’re only going to make things worse!

If rust is so bad in your tank that it’s seriously weakened your unit’s walls, then – apologies – but you’ll probably need to buy a new air compressor altogether.

A tank explosion is not only going to destroy your air compressor, it stands to damage other tools and machines nearby or connected. Not only that, but you could put yourself – and others – in harm’s way. If in doubt, get a new air compressor and start looking after it a little better – tough love, we’re afraid!

4 ways to prevent rust in your air compressor tank

Let’s preface – ultimately, there is always going to be some wear to the inside of your air compressor tank. It’s inevitable. However, there are a few different ways through which you can reduce the potential rust levels set to develop. It’s all about keeping moisture low, and drying out the tank as much as you can.

Here are four great ways to prevent rust in your air compressor tank that we’ve tried and tested ourselves.

Keep draining your tank

Draining your air compressor tank is the number one way to reduce moisture. The reason for this should be pretty obvious! If you keep water and moisture in your tank, that iron-hydrogen-oxygen reaction is going to speed up.

Generally, it’s a good idea to drain your air compressor tank at least once a week. However, to really drive down rust potential, it’s worth draining after every use. Even if you don’t use your compressor very often, moisture doesn’t care – rust can build up in even the best air compressors or the most robust tanks on the market. If in doubt, drain it out.

Try keeping your drain open

You don’t have to keep your drain open if it’s awkward or if it doesn’t make sense to you, but it’s another surefire way to slow down the development of rust. We can assure you it’s well worth trying if you can.

Leaving your drain open after you’ve removed as much water as possible will help to take care of any drips and drops left behind. Open drains will dry on their own, meaning moisture will reduce naturally in the open air. 

We recommend leaving your drain outlet open, if you can, on the night of your last draining. Leave any stray drips to dry out while you sleep, and come back to your compressor tank fresh the next morning to re-seal. If you can get into this habit, it’ll really help to keep rust at bay.

Lubricate your tank with specialist oil

Sometimes, it may be worth using an anti-rusting oil or lubricant to prevent the chemical reaction from taking place. In our experience, nothing really beats keeping your tank as dry as possible. However, for extra protection, oiling up your tank really won’t do any harm.

However, do make sure that you purchase and use a tank oil that is developed purely for this purpose, and for an air compressor. Oil buildup can also lead to problems in a compressor tank, too, such as clogging if left to fill up valves and crust over. Therefore, ensure you keep up with your maintenance schedule if you’re applying any new treatments.

Always follow the label on any product you buy for your air compressor tank, as using too little won’t give you the results you desire, and too much could cause serious damage.

Try using an aftercooler

Where possible, you might also wish to use an aftercooler or air dryer to help suck up the last droplets lingering in your air compressor tank. We’d normally recommend an aftercooler for bigger tanks, particularly where it is not always easy to get every drop out through draining alone.

Aftercoolers are preventive tools that actually stop water vapor from ever building up in your air compressor’s tank. Therefore, you’re stopping the problem before it even arises. Essentially, it filters and encloses warm air before cooling it – and dispersing it directly into your tank.

This is a great add-on that might cost you a little extra money, but for the sake of preventing nasty rust and weakening your tank, it’s likely to be a solid investment. Certainly, consider it if you’re running a larger compressor than most.


Rust has the potential to do serious damage to your air compressor, and if you don’t take steps to prevent it, you could be facing major problems further down the line.

The bottom line is to never tackle existing rust yourself and to focus on preventing it from getting worse. If it’s already too far gone, then it may be worth upgrading your tank.

Once you’ve got a firm maintenance and cleaning schedule in place, you’ll find rust prevention pretty simple – and you’ll thank yourself for taking this level of care for the months and years ahead.