Do not use fixtures that depend on an unpowered pump to remove wastewater. Water can accumulate even though the taps and cistern still function.
What the observation means
A toilet flushing into the unit is not proof that discharge can continue. Everyone using the property needs to know which facilities are affected.
A useful next step
Use an alternative facility until normal safe operation is established. Do not perform test flushes during the outage. When power returns, follow the model's instructions and seek help if the system fails to clear or shows an alarm.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.