Water House Restaurant uses water from the adjacent Regent's Canal as a passive energy source. The design uses the canal water as a heat source and heat sink, delivering heating and cooling to the restaurant via a heat pump. In summer, the space is conditioned using chilled cooling sails suspended from the ceiling. Cold water generated by the heat pump is passed through the cooling sails, which provide radiant cooling overhead. Under floor heating is used in winter. Further cooling and heating is provided by the fresh air displacement ventilation system, which supplies conditioned air at low level through panels made of woven wicker. The energy efficient system reduces the power demand substantially for heating, cooling and ventilation.

Designed within an existing shell, the interior of the restaurant reflects its ethos. The concrete soffit has been left exposed to maintain the simple and no-nonsense quality of the building. Waugh Thistleton have selected the material palette on the basis of its carbon footprint. Natural products and non-exotic finishes such as clay-based paint and linoleum flooring have been sourced from local suppliers. Timber, sourced from FSC managed forests, has been used on bar tops and hand woven wicker clads the bar fronts and ventilation grills, giving the space a natural aesthetic.