The warning from the Institution of Mechanical Engineers follows the hottest, driest summer since 1976 – with average June temperatures of around 19C (66F).
Its report, Water: Drought And Flood, calls on all major UK cities to publish research on their infrastructure needs, which could include improving drainage or water recycling in new buildings.
The organisation called for a government-run awareness campaign on the value of water, and for the water industry to create drought and flood sustainability plans – warning that local and national politicians need to get planning for decreasing water availability, while we all need to try and preserve as much as possible.
Dr Colin Brown, the institution’s chief executive, said the report builds on “substantial work” done three years ago and the hot summer has brought the issue back to the spotlight.
Scientists tell us extreme weather patterns are here to stay and environmental charity EarthWatch says water resources are in crisis and we must learn more about how to manage them.
Senior research manager Steven Loiselle is working with “citizen scientist” teams in Oxfordshire to measure data on the river water’s quality.
Volunteers test the river’s clarity and cleanliness, and upload the results to a global database.
Mr Loiselle showed Sky News a phosphate test on one part of the River Evenlode, which indicated levels of chemical are higher than they should be.
Too much phosphate can kill fish, and cause over-blooming of algae.
He said: “Climate change is going to cause extreme events.
“So we’re going to have more heavy rains, very dry summers, we’re going to have things that these ecosystems are not used to handling.
“Any aquatic ecosystem can absorb and transform a certain amount of pollutants, let’s say nutrients.
“If we have extreme events that capacity to transform gets reduced, gets challenged.
“What climate change is going to do is constantly push the limits of these ecosystems to deal with it.”
He added: “It’s easy to say: ‘Oh the farmers are using the most’, but certainly if your house has misconnections, you’re a major source.
“If you’re using an excessive amount of water, an excessive amount of soap and detergent in your house, you’re not any better.”
Anne Miller, from Wild Oxfordshire, said: “If you, on a dry period, are washing cars or doing other things where you tip stuff down the drains, that can have a really big effect on wildlife in the river.
“Suddenly a great slug of washings go down with all the things that might be in there, your phosphates and so on.”
Thames Water has partnered with Earthwatch to carry out the citizen scientist tests.
After it was ordered to pay £120m for failing to control leaks, the company says it’s improving its management of them, and has acknowledged it has a role to play in preserving water.
Yvette de Garis, Thames Water head of environmental regulation, said: “Programmes like this are important because we need people to understand that the water they use in their home really affects what happens to beautiful environments like this.
“Actually if they use less at home and everybody does their bit, rivers like this are much more resilient to the sorts of summers we’ve seen this time round.”
Mr Loiselle said there was plenty we could do to look after our water supply, adding: “Being careful what we buy – low phosphate, no phosphate detergents; being careful in our gardens – if we have a beautiful green lawn and we’re fertilising the heck out of it, 70% of that is going to end up in the waterway, so you should be thinking twice.”
Ms Miller encouraged people to enjoy their local rivers and waterways, saying: “Once children connect with nature – and they do, they love all this – that’s the most powerful thing we can do as far as we’re concerned.
“It’s our chance to really change the way that things are going to go with the future.”