Water rates in Alderney will rise by 10% to help pay for cleaner drinking water, the island's States has agreed.
Members voted on Wednesday to spend £700,000 installing a centralised filter system at the Battery Quarry.
It is part of a programme to build a resilient water infrastructure and make drinking water conform to UK standards.
Moira Sleeman, the BBC's Alderney reporter said: "Historically the drinking water has been of variable quality and the butt of many jokes."
An alternative plan, which was £30,000 cheaper, was rejected as it did not include any capacity for future expansion of the system if it became necessary.
The increase in rates will come in during September.