Some 7.9 million vehicles fail their MOT every year. Out of the 35.2 million motors tested annually, that accounts for 28 per cent deemed not to be road worthy.
Analysis of last year's test data shows more than 200,000 failed due to one specific part failing - and it's one of the cheapest components on a car that costs as little as £1.99 to replace.
According to DVSA records scrutinised by eBay, 216,388 MOT fails in 2025 were triggered by faulty window washer jets. That accounts for an average of 592 cars and vans flunking the roadworthiness assessment on a daily basis.
Further research by eBay suggested this is because a quarter of motorists are unaware that a faulty washer jet can trigger an MOT fail.
Windscreen washer jets are fundamental to keeping a windscreen and rear window clear. As such, they are deemed an essential safety component that must be operating without issue in order to pass an MOT.
Despite a washer nozzle being relatively simple to fix and cheap to replace, 13 per cent of drivers admitted to never checking the condition of their washer jets. A fifth of the 2,000 UK motorists polled said they only check them when they have an MOT or service booked.
The most common issue with a washer jet is that it's become clogged with dirt accumulated over time and miles, which requires for them to be cleaned or replaced entirely. Removal and then cleaning with a de-scaler or using pressurised air to blow dirt out of the nozzle will typically solve the issue.
Because they are so cheap, many drivers simply buy replacements rather than spending time trying to fix faulty washer jets. These parts are typically sold online for as little as £1.99, though usually they cost £5 to £10 for a pack of two.
While a retest is often free if completed within 10 working days at the same test centre, if a vehicle is taken to a different garage a partial fee (up to £27.43) may apply, or a full fee if returned after the original failed attempt.
Data from the DVSA also shows that incorrect alignment of washer jets accounted for 29,405 MOT failures in 2025. In eBay's survey, three in five car owners admitted they do not know how to re-align them correctly.
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Over 216,000 cars failed MOTs due to faulty £2 washer jets that many drivers never check.
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This shows how simple maintenance oversights can lead to costly MOT failures and potential safety risks.
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Clogged washer jets can often be fixed by cleaning with de-scaler or pressurized air instead of replacing.