Local authorities paid out more than £20 million in compensation last year to drivers whose vehicles were damaged by potholes, according to research.
Which? said councils in England and Wales paid a total of £22.8 million to road users for pothole damage, with authorities in the north west of England paying out the most at £8 million, according to figures collated by the Asphalt Industry Association.
The Government commissioned a Potholes Review in 2011 and allocated an extra £200 million for local highway authorities, citing a "significant increase in the number of potholes on the already fragile local highway network".
But Which? found that the backlog of road repairs per local authority in England is getting bigger, growing from £53.2 million in 2009 to £61.3 million last year. Local authorities have estimated that it would cost £12.93 billion to clear the entire road maintenance backlog in the UK.
Which? executive director Richard Lloyd said: "Potholes are a menace for all road users. With temperatures plummeting this week and the bitter weather conditions set to continue, the backlog of repairs could grow again. Drivers should help themselves and everyone else on the road by pointing out potholes to the local council."
The watchdog said the chance of claims being successful depended on whether the local authority was aware of the pothole in the first place and had not repaired it or if it had not followed road maintenance guidelines.
Potholes can be reported via a council's website. The Directgov website lists which council is responsible for specific roads.
Local Transport Minister Norman Baker said: "We are providing councils with more than £3 billion between 2011 and 2015 to maintain their roads and pavements and last month announced an extra £215 million to help councils get the best out of their road network.
"This is on top of the additional £200 million we gave to councils in March 2011 to repair local roads damaged by the severe winter weather in 2010. It is ultimately up to local highway authorities to determine how they prioritise their funding, but we want to help them get the best value for money.
"That is why we are funding the Highways Maintenance Efficiency Programme which helps councils work together to deliver a first class service to their residents, at the same time as saving money."