Water was everywhere in the first projects year 9 students at Kellyville High School took on as part of a new elective class for gifted and talented students.
Science head teacher Fabio Caprarelli said the students investigated topics as wide-ranging as water-borne diseases malaria and giardiasis, the link between drought and suicide for farmers, and the impact of the composition of amniotic fluid on the health of an unborn baby.
They liaised with university scientists and presented their projects to a group including Sydney Water and Hills Council representatives.
"To see the depth that their learning has taken is just incredible," Mr Caprarelli said.
"The students went through the syllabus and designed their own marking criteria, so they were assessed on things that they deemed important."
Groups also looked at the state of water on Mars and closer to home at Smalls Creek.
Tamar Selwood said her group found high levels of ammonia and salinity in the creek after testing samples in a lab at the University of Western Sydney's Hawkesbury campus.
"It was really good to go there and experience university levels of science," she said.
"We also looked at possibly using those [high salinity] bodies of water to fight bushfires."
Peer Breanna Weigel said the group found plants were dying due to high levels of salinity and ammonia in the water, while Simran Kerai said the scope of research meant students looked forward to that class more than others.
"When you're passionate about it you tend to want to learn more and you look forward to the class," she said.