Why this matters for the Dart: the water in your taps is taken from the environment, and every litre you save is a litre that can stay in a Devon river, and a litre the sewage works never has to handle.
The average person in England and Wales uses 143 litres of water a day 38. It arrives so reliably that it is easy to forget where it comes from: rivers, reservoirs and groundwater. Using water efficiently means less water needs to be taken (the technical word is abstraction) from rivers and aquifers, which protects the wildlife that lives in and depends on them 38. This is directly relevant here: the Environment Agency's catchment data for the Dart lists surface water abstraction by the water industry as a pressure affecting the river's flow 42. And almost everything you use indoors leaves as wastewater, so saving water also shrinks the load on the sewage works and sewers that overflow into the river when overwhelmed.
So water saved at home counts twice for the river: less taken out at the top, less to handle at the bottom. Here are the savings that add up fastest.
Fix the leaky loo. A toilet cistern that trickles or hisses between flushes can waste between 200 and 400 litres every single day 40, often invisibly. A simple test: put a dry piece of toilet paper against the back of the pan an hour after flushing; if it wets or tears, you have a leak. Most leaky loos are a cheap flush-valve or washer fix. Why it helps the Dart: it is probably the single biggest hidden water waste in any home. How hard: easy to spot; the repair is easy for a plumber and moderate for a confident DIYer.
Shorten the shower. The average showerhead uses about 12 litres a minute, and the average shower lasts around 10 minutes, which can mean up to 150 litres per shower 38. Waterwise, the UK's water efficiency charity, suggests keeping showers under four minutes 39. A shower timer or a four-song playlist does the trick. Why it helps the Dart: showers are one of the biggest water uses in the home, and every litre saved is abstraction and treatment avoided. How hard: easy.
Turn the tap off while brushing. A running tap wastes approximately 6 litres a minute 38. Why it helps the Dart: small, but twice a day, every day, for everyone in the house. How hard: easy.
Run full loads. Fill the dishwasher completely before switching it on, and do the same with the washing machine; and only boil the water you need in the kettle 39. Why it helps the Dart: fewer cycles means less water abstracted and less wastewater to treat. How hard: easy.
Ask about free water-saving devices. South West Water provides free water-saving devices to customers 18. Why it helps the Dart: free is a good price for saving thousands of litres a year. How hard: easy.
Install a water butt. A water butt collects rainwater from a downpipe for garden use. The Royal Horticultural Society notes that even the roof of a small shed can collect 2,500 to 3,500 litres of rainwater a year in the drier parts of England, enough to fill ten or more standard 240-litre water butts 41; a Devon house roof, with Devon rain, will do considerably better. Use it for watering, rinsing tools and washing wellies. Why it helps the Dart twice over: it replaces tap water (less abstraction), and it holds back roof water that would otherwise rush into drains and combined sewers during storms, which is exactly when overflows spill (your drive & garden continues this theme). How hard: easy to moderate; a butt, a stand and a downpipe diverter kit is an afternoon's job.
Water the garden from the butt, not the hose, and water in the evening so less evaporates 41. How hard: easy.
None of this asks you to be miserly. It asks you to notice that the tap and the river are the same water, a few miles apart.