Earth’s surface may be 70 percent water but many places are struggling to access it. We look at a range of water supply options including delivering it by tanker. In Malta we meet a man trying to solve its water problems, with a clever contraption to recycle sewage. Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk Presenter: Marnie Chesterton Produders: Cathy Edwards and Marijke Peters (Image: Tanker ship. Credit: Getty)