How to check windscreen wash

Consumer Editor

4 minute read|28th Aug 2026

Windscreen wash, screenwash, washer fluid - whatever you might call it, it's vitally important for seeing where you're going when driving.

While many motorists remember to check their oil and coolant levels, the screenwash level often gets overlooked. Yet it's arguably as important, unless you're fine with stopping every couple of miles to clean spray, road salt and mud off your windscreen by hand.

Most modern cars will warn you if you're low on screenwash - but if you've just set off on a long journey that warning can come too late. That's why it's important you know how to check your levels before leaving is important.

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How to fill your windscreen washer reservoir

Park your vehicle on a level surface and switch off the engine.
Allow the engine bay to cool if you've been driving.
Open the bonnet and secure it using the bonnet stay if required.
Locate the windscreen washer reservoir, usually identified by a windscreen or water spray symbol.
Remove the reservoir cap and place it somewhere safe.
Check the type of screenwash you're using and dilute it if the manufacturer's instructions require it.
Carefully pour the screenwash into the reservoir, using a funnel if necessary to avoid spills.
Fill the reservoir until it is nearly full. Most washer bottles do not have minimum and maximum level markings.
Avoid overfilling or spilling screenwash onto engine components.
Securely refit the cap, close the bonnet, and test the washers to ensure the system is working correctly.

Check windscreen washer fluid

Here's how to find the windscreen washer reservoir and check your windscreen washer fluid level.

With the engine off, open the bonnet and find the washer bottle. It usually has a blue cap with a windscreen symbol. If you can't find this easily check your owner's manual.

Remove the cap then pour in the screenwash until it reaches the top. You can use a ready-mixed screenwash or dilute a concentrate solution according to the instructions on the bottle.

Secure the washer bottle cap and you're good to go. Remember, keeping your screenwash topped up doesn't just keep your windscreen clean.

There is no specific law stating the washer bottle must be full at all times. However, motorists must ensure they have a clear view of the road, and vehicles must be fitted with functioning windscreen washers if they were originally equipped with them.

Driving with inadequate visibility could lead to penalties and may result in an MOT failure.

Which type of screenwash should you use?

Not all screenwash products are the same, and choosing the right type can help keep your windscreen clear in different driving conditions.

Summer screenwash

Designed to remove insects, dust, pollen and general road grime
Ideal for warmer months when bug splatter is more common
Typically offers little or no protection against freezing temperatures

Winter screenwash

Contains antifreeze additives to help prevent the washer fluid from freezing in cold weather
Effective at removing road salt, dirt and oily deposits that build up during winter driving
Particularly useful during periods of frost, snow and freezing temperatures

All-season screenwash

Combines cleaning power with freeze protection
Suitable for year-round use in most UK driving conditions
Often the most convenient option as it avoids the need to switch products between seasons

Can I use water?

While it may seem like a quick and inexpensive alternative, water is less effective at removing dirt, insects, road salt and oily residue from your windscreen.

It can also freeze during cold weather, potentially preventing the washer system from working when you need it most. For the best visibility and protection, use a proper screenwash solution, especially during winter months.