The hotel’s towels are washed only on request, the buffet breakfast includes freshly baked organic bread, and the pre-dinner cocktails are suffused with herbs from the kitchen garden.

Most hotel welcome packs now include elaborate details of how your stay is helping to save the planet, but when you get to the bit about the swimming pool, the eco claims begin to sound more like greenwash. 

Typically, a wildlife-friendly garden habitat will have been turned into a sterile basin filled with gallons of water. Keeping such a huge body of water warm throughout a season can guzzle thousands of kilowatts of energy, especially outdoors where the water needs to be continually heated to overcome the cooling effect of evaporation. 

In addition, a pump is required to drive a filter; this collects debris such as leaves and hair, circulates water to prevent it stagnating and disperses disinfectants (to deal with nasties such as sweat and urine, as well as personal care products and sunscreens). Not only is this energy sapping, but people are beginning to question the impact of these chemicals on our bodies and on the wider environment.

“We call it the ‘wellness paradox’,” says George Ingledew of Origin Aqua, a company that specialises in making swimming pools more sustainable. “Visitors spend lots of money on holistic health and wellbeing treatments, but then are willing to jump into a pool full of chemicals.”

Ingledew says that it has become easier to reduce the carbon emissions of swimming pools thanks to more widely available energy-saving measures and developments in ground- and air-source heating technology, but that the use of chemical sanitisation systems is still widespread. His company offers a solution in a bio-digestion filtration mechanism housing billions of beneficial microbes which out-compete aquatic pathogens. A process of microbial magic, it’s known as biological ‘predation’, and negates the use of chemical disinfectants.