Rainwater harvesting system with two interconnected 65.000-litre RoDrive tanks, for a total of 130.000 litres. The two high-strength HDPE tanks, around 29 metres long as a set, were joined by PE d200 pipework welded by electrofusion, with DN400 inlet and outlet, a DN250 overflow and DN600 access shafts with cast-iron covers. Buried under asphalt paving, they withstand truck traffic of up to 40 tonnes without a concrete cover slab.