“Why do we use clean water to flush our toilets at home?“ queries Annie Mills, of De Montfort University. Water scarcity in the UK is accelerating, and toilet flushing amounts to around 30 per cent of a person’s total water use, about 43 litres per person per day. Annie’s award-winning ECHO automated water-recycling system is gravity-fed and uses shower and bath water to flush a down-stairs toilet. It will be shown on film.