Maintenance should follow the property.
There is no single cleaning interval that fits every commercial property. Restaurants, multifamily buildings, manufacturing facilities, offices and other businesses can place very different demands on drainage systems. A useful plan starts with the lines that repeatedly create problems and the conditions found during service.
Track stoppages, cleaning dates, affected fixtures, known grease or solids exposure, root history and inspection findings. Over time, that record can help identify which lines deserve proactive attention and which do not.
The goal is not to clean every line as often as possible. It is to use actual property history to reduce preventable interruptions while recognizing that cleaning does not repair structural pipe defects.
When to bring in a drain professional
If the symptom is recurring, several fixtures are involved, wastewater is backing up, or the cause is unclear, professional evaluation can help determine the appropriate next step. The visible symptom does not always identify the location or condition causing it.