Councils will have to cut money from services such as libraries, museums and fixing potholes because of the "escalating" cost of caring for the elderly, a new report warns.
The Local Government Association (LGA) said £1.1 billion would be needed to be diverted from other areas in 2015/16 to meet the rising cost and demand for adult social care.
Leaders said core government funding for 2015/16 was being cut by 8.8%, leaving local authorities having to find extra money for "shrinking" budgets.
The LGA suggested councils will have little money left for any other services by the end of the decade unless the "crisis" in funding was tackled.
David Sparks, who chairs the LGA, said the issue is "taking a toll" on people who rely on councils to fix roads and keep libraries open, adding:
The Government said it had "sought to protect" spending on social care "as much as possible", but said the allocation of resources was a matter for councils.