Burnham-On-Sea residents will see their council tax bills going up by 5.24% from April.
For average Band D households the decision by Somerset County Council means an overall increase of about £52 over the year.
Council tax has been frozen in Somerset for the past five years, but a vote to approve the increase was carried during a vote by councillors, with 31 in favour of the proposal, 20 against and four absent.
£2.7m will be directed towards the Somerset Rivers Authority (SRA), formed after the 2013-14 Somerset Levels floods.
Councillors also agreed to invest £75m on capital projects for road-building, schools and economic growth.
The council’s leader, Conservative John Osman, said: “We’re really proud that we’ve been able to freeze council tax for so long. When you’ve got to find £25m there are no easy decisions, so reluctantly we’ve made this decision to put the council tax up, but for that money residents will get flood prevention and get their adults and children looked after.”
But the leader of the opposition at Somerset County Council, Liberal Democrat Ross Henley, voted against the tax rise and said: “They’ve increased council tax by 5.24%, by far the biggest tax rise in the country. No other council has even broken 4% and not only that they’ve made massive cuts to mental health, autism budgets and bus services as well.”
The £7.8m in cuts include cutting £762,000 from the vulnerable adult services budget, £500,000 from bus services and £200,000 in library cuts. Some 90 posts will also go at the council.
The council has also agreed to support plans for devolution that would give it more power to act on future strategies.