What Car? Q&A - Is driving without screenwash illegal?

Q: A policeman told my friend that he can be prosecuted for having an empty windscreen washer bottle. Is this true?
Bob Ferrett

A: Under British motoring law, a car is unroadworthy if the driver cannot free the windscreen from grease and grime, and if your washer doesn't work you could fail your MoT, so technically you could be prosecuted for having an empty washer bottle.

Remember, screenwash contains compounds which break down the grease and helps the wipers to clear the screen quickly and efficiently. Using just water could make it very difficult to see out the screen.

You might be tempted to use washing-up liquid, but this should be avoided. Over time, the foaming agents that make the bubbles become concentrated, leaving you with a badly smeared screen which you won't be able to see through.

This type of detergent could eventually have a detrimental effect on your car's paint too, and may freeze in cold weather. Many dishwashing liquids also contain salt, which will corrode bodywork. For the same reason, you should never use it to wash your car.

Splashing out on a dedicated screenwash is wise, but avoid mixing different brands, because the chemicals used can be different and could lead to smears. You should also change the strength of screenwash depending on the season. Colder weather requires a stronger mix to avoid freezing and help you clear an icy screen.