Technical Booklet N Drainage·Page 7·82
Rainwater drainage requirements
Rainwater drainage systems must be properly sized, constructed, watertight, and ventilated to convey rainwater to appropriate discharge points, with accessible points for maintenance.
Rainwater drainage shall—
(a) consist of pipes and fittings—
(i) of such size, layout, construction and watertightness; and
(ii) with sufficient ventilation,
to ensure the hygienic conveyance of rainwater to a surface water or combined sewer, a soakaway or a watercourse; and
(b) have such means of access as is necessary to facilitate the clearance of blockages.
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