The increasing climatological effects of global warming have reinforced the importance of determining the greenhouse gas (GHG) emissions associated with different design solutions. The main aim of this study was to evaluate and compare the environmental impacts, in terms of Carbon Footprint, of two products heavily used within the water management industry, namely concrete and High Density Polyethylene (HDPE) pipes. The study was predominantly focused upon large diameter pipes, i.e. with an internal diameter from 600mm to 1800mm. The results reported herein encompass cradle-to-gate (manufacturing) and cradle-to-site (manufacturing plus transport) scenarios in terms of carbon dioxide equivalent (CO2e) GHG emissions. On the whole, concrete pipes were found to have greater Carbon Footprint associated with them, compared to equivalent sized HDPE pipes, in both cradle-to-gate and cradle-to-site scenarios. In particular, it was found that on average concrete pipes tended to produce 21% and 95% more GHG emissions in from cradle-to-gate (in terms of kgCO2e per unit length) and gate-to-site (in terms of kgCO2e per unit length, per km) respectively, compared to the equivalent HDPE pipes. The results suggested that HDPE pipes are a more carbon efficient product to be used within water management systems as opposed to concrete pipes. Therefore, it could be inferred that HDPE pipes have the potential to actively aid the construction industry in their formidable task of reduction GHG emissions in accordance with the UK government’s forthcoming targets. Keywords : Carbon Footprint, Climate Change, Large Diameter Pipes, Concrete, HDPE.