Water: drought, ENEA's 20 tips for saving water (and energy)

Rule number one: don’t waste water. A tip that is always valid, but even more so during a water emergency like the one we are currently experiencing, marked by the worst drought in 10 years. To combat water waste and make its management more sustainable, ENEA has drawn up a 20-point guide with suggestions and good practices, mistakes to avoid, and also solutions and technologies for saving water (and energy), especially in the residential sector. In short, when at home reduce leaks and waste and use it more rationally. In general, employ less water-intensive processes and systems, purification and reuse, improved efficiency and digitisation of the waterworks, but also good practices by families and schools.

1. Keep the water system efficient and check for hidden leaks: it is estimated that up to five litres per day are lost with a dripping tap.
2. Close the tap tightly to prevent water from flowing unnecessarily. For example, when washing hands: in one minute you can avoid wasting at least six litres of water. If you let the water run while brushing your teeth you can waste up to 30 litres (compared to only 1.5 litres if you turn it off). Similarly, turning off the tap while shaving saves up to 20 litres.
3. Collect unused cold water when waiting for the hot water to arrive. First do things that require cold water (e.g. brushing teeth) and then those that use hot water (e.g. shaving).
4. The same goes in the kitchen, when preparing food or washing vegetables use basins instead of running water. It is estimated that about six litres of water per day per capita are consumed for drinking and cooking and at least 40 litres for washing dishes by hand. However, wastage can be as high as 12 litres per minute if the tap is not turned off.
5. Reuse water from cooking pasta or washing vegetables to rinse dishes before putting them in the dishwasher or for watering plants (when not salted).
6. Always use dishwashers and washing machines with a full load. It is estimated that for a dishwasher load (class A) without pre-wash up to 15 litres (7 litres in class A++) are used, while for a washing machine load (class A) 45 litres are used. Also prefer washing programmes with low temperatures (40-60° C). Furthermore, the installation of solar panels would avoid the consumption of electricity to heat the water needed for household appliances.
7. Whenever possible, prefer taps with sensors or that are aerated to reduce water flow and increase washing effectiveness, taking care to maintain them (e.g. by using a scraper).
8. Install double-button flushers to save up to 100 litres per day, considering that up to 16 litres of water are used for each use of single-button models.
9. Use a shower instead of the bathtub to save up to 1,200 litres per year. It is estimated that an average of between 100 and 160 litres of water is consumed to take a bath in the bathtub, while a maximum of 40 litres is consumed to take a five-minute shower, and even less if you turn off the tap when you soap up.
10. Shut off the water at the mains in the event of prolonged periods of non-use (e.g. when leaving on holiday).
11. Install rainwater collection systems for non-drinking uses (washing toilets, washing cars) and for watering (rainwater is less hard and more agreeable to plants), avoiding watering during hot hours to reduce evaporation. Each year an average of about 800 mm of rain falls in Italy. This means that in an area of approximately 80 m² you can collect the water needed for one person for a year.
12. Use timed, drip or sub-irrigation systems for irrigation because of their greater efficiency.
13. Avoid washing your car using drinking water to save 400-500 litres.
14. Cover the surface of pools with tarpaulins to prevent evaporation.
15. Recover condensation water from air conditioners or the dryer for domestic use, such as for ironing.
16. Diversify the use of water according to its quality (drinking, rain, grey, black - see fig. 2).
17. In the garden, around the plants, distribute adequate mulching[1] so as to keep as much water as possible in the soil. Also prefer plants that need less water and take care not to water impermeable areas.
18. Where possible, use technologies for the reuse of grey water, i.e. water generated by personal hygiene. A dedicated system to recycle water from showers, washbasins and bathtubs, and in some cases, from condensation from air conditioners or boilers, ensures that it is treated for subsequent “secondary” uses such as flushing toilets, watering green areas, and washing.
19. Install plant-based roof coverings and roof gardens. These solutions absorb up to 50% of rainwater and slow the flow of rain into the city's water system, reducing the possibility of flooding in the event of heavy rainfall. Green roofs also thermally insulate the roof, reduce particulate matter and promote a more pleasant microclimate, reducing the albedo effect.[2]
20. On surfaces outside buildings, use drainage pavements in order to preserve the natural character and permeability of the site, encourage groundwater recharge, reduce subsidence and mitigate the heat-island effect.