Key legal question
Whether the municipality could revoke a final water connection fee decision and increase the fee retroactively.
Extracted holding
The original fee decision was protected by legitimate expectations and could not be revoked; the later reassessment was unlawful.
Extracted reasoning
Gebührenverfügungen are generally irrevocable once final and paid. The initial error was not obvious to the addressees, so trust protection prevails over correct application of law.