The 100-room NH Campo de Gibraltar hotel in Algeciras, Spain was opened in 2009 with a clever grey-water recycling system, which was installed along with another successful case at the NH hotel (Hesperia hotel in Cordoba, Spain). Grey-water is collected separately from basins and showers, then treated and recirculated for toilet flushing, which significantly reduces potable water consumption. Grey-water recovery systems require separate pipework, and therefore, are difficult to retrofit, which puts new hotels at a distinct advantage in being able to install such systems from the ground up. The payback periods can vary from 2 to 15 years depending on the type of the system and the cost of fresh water saved. The hotel reported relatively high system maintenance costs of between € 2 000 and € 3 000 per year, which has an effect on the overall benefits. Nevertheless, the novel recycling system built into NH Campo de Gibraltar's property managed to cut annual water consumption by 20 %, with an equivalent reduction of sewage as well.