Method for determining a condition indicator of a water analysis apparatus

A water analysis apparatus configured to measure at least two different technical parameters, the water analysis apparatus comprising:

• at least one of a sensor and a counter configured to determine a respective parameter value for each of the at least two different technical parameters;
• and
• a condition indicator configured to determine an overall condition of the water analysis apparatus by a method comprising:
• determining a respective parameter value for each of at least two different technical parameters of the water analysis apparatus with the at least one of a sensor and a counter;
• determining a respective deviation value of each of the parameter values with respect to an associated respective parameter reference value for each of the technical parameters;
• determining a respective deviation relevance value from each of the deviation values using a respective parameter-specific deviation relevance function for each of the parameter values, the parameter-specific deviation relevance functions being different from each other;
• and
• calculating, using an indicator function, the condition indicator for the water analysis apparatus from the determined deviation relevance values.