9. The operator of municipal wastewater treatment works must list all the overflows of wastewater that occur at the operator’s treatment works, using a device to record their frequency, the time when they occur and their daily cumulative duration, or by observing the displacement of a visual feature installed to that effect each week.
When an overflow of wastewater not caused by a case of emergency occurs at the overflow point, the operator must install the device provided for in the first paragraph within a year of the occurrence of the overflow concerned.
Where a device is installed, it must be maintained in good working order at all times.