sentences:  The sewer charge is 70% of the water charge.Durban distinguishes between a lower tariff for semi-pressure service for houses in low-income settlements with roof tanks and a higher full pressure service for "formal" housing areas.Semi-pressure service is free until 9 cubic meters, while full-pressure service costs R9.50 per cubic meter until 9 cubic meters per month, and R11.25 until 25 cubic meters.