More than £1 million extra a week could be spent by Surrey County Council within 20 years on care for over-65s.
Office for National Statistics figures reveal the number of people living past 65 is expected to rise 107,000 to 328,000 by 2036.
Analysis of the data shows that of those an extra 2,600 over-65s will fall under the county council’s care – up by almost 50% from 5,400 currently.
That would add an estimated £59m to the authority’s annual adult social care bill* – equivalent to more than £1.1m a week or around 15% of this year’s budget.
Currently demand is increasing by £24m a year, while the 2% council tax precept introduced nationally earlier this year to fund adult social care raises £12m.
Mel Few (pictured), Surrey County Council’s Cabinet Member for Adult Social Care, said: “The fact that more of us are enjoying a longer, more active old age is a cause for celebration.
“Unfortunately there’s also a cost attached to that and, while we’re committed to doing the very best for people in later life, these figures really emphasise the strain growing demand and escalating costs are putting our finances under.
“Those pressures already mean that the council needs to spend more than £20m extra every year on caring for older people and if these latest estimates are correct that could become almost £60m annually within two decades unless things change.”
* All estimated figures are based on current legislation, costs and ways of working.