Insurers expect the total bill for Storm Desmond to reach around £520 million.
The Association of British Insurers (ABI) said its members have already helped nearly 1,500 families to get into alternative accommodation and have so far made emergency payments totalling £2.6 million.
Emergency payments are cash for affected families and businesses to spend on items they need immediately, such as replacement Christmas gifts for ones that have been destroyed, as well as food, clothing, staff salaries and domestic appliances. Costs for alternative home or business accommodation are paid directly by insurers.
The extreme weather which hit the UK earlier in December resulted in major flooding to properties across swathes of Cumbria, Lancashire and in the Scottish borders.
St Michaels on Wyre and Lancaster were among the worst affected areas in Lancashire.
The ABI said initial estimates suggest the final amount its members will pay out to affected customers is likely to be around £520 million.
Of the emergency payments made so far, £1.7 million has been to domestic customers and £900,000 to businesses.
Customers have made 23,700 claims for property damaged by either flood or storm. Just over 4,000 of these claims relate to businesses.
The ABI also said that 2,800 motor claims have also been received and more than 4,500 initial visits have been made by loss adjusters, who handle the more severe claims.
James Dalton, director of general insurance policy at the ABI, said: “Being flooded is hugely traumatic and insurers have worked round the clock to get the repair process under way, provide immediate payments to people affected and find families somewhere warm and dry to stay.
“The flood waters have mostly receded but for affected families and businesses the impact is going to be felt for months. Insurers and their expert teams will be there for the long haul to help communities rebuild and repair.