To save water, act first where it flows most: the shower, which with baths accounts for 39% of domestic consumption, then leaks, toilets and appliances. A French resident uses 143 litres a day (SISPEA, 2024); the habits below, ranked by litres saved, can cut several dozen litres with no loss of comfort.
Where to start saving water?
Start with the shower. It weighs 39% of a household's consumption and uses about 12 litres a minute with a standard shower head: 5 minutes is 60 litres, 10 minutes 120 litres, the equivalent of a bath (150 to 200 litres). Three habits count: shorten the shower, turn the water off while soaping (about 20 litres saved) and fit a water-saving head or regulator, which halves the flow. The fourth lever, the most powerful, is to see your consumption during the shower: in the Molleau pilot run with Hénéo, displaying litres cut the average shower from 45 to 34.7 litres, −23%, without changing the flow rate.
Which habits save the most litres?
| Habit | Litres saved | Source |
|---|---|---|
| Fix a dripping tap | 4 L an hour, 35 m³ a year | CIEau |
| Fix a leaking toilet cistern | up to 600 L a day | Selectra, from utilities |
| Display litres during the shower | −23% per shower, ≈ 10 L per shower | Molleau × Hénéo pilot |
| Water-saving shower head or regulator | flow halved, from 12 to 6 L a minute | Selectra |
| Turn the water off while soaping | ≈ 20 L per shower | Selectra |
| Dual-flush toilet | 4 to 6 L instead of 9 to 12 L per flush | Selectra |
| Turn the tap off while brushing teeth | ≈ 12 L a minute | INC |
| Efficient dishwasher instead of hand washing | 10 to 20 L per cycle, 6 L for the most efficient | Selectra |
Volumes depend on your fittings' flow rate and network pressure; the orders of magnitude above are those published by the sources cited.
How do you spot a water leak?
To spot a leak, read your meter in the evening, use no water overnight, then read it again in the morning: if the index has moved, there is a leak. Toilet cisterns are the first suspects; an invisible trickle in the bowl can lose up to 600 litres a day. A connected water meter, which sends a daily reading, flags this kind of continuous consumption. Our guide on tracking water use per flat details solutions for buildings.
Why does hot water count twice?
Hot water counts twice because it costs the water and the energy to heat it: about 0.03 kWh per litre to go from 15 to 40 °C. A 45-litre shower therefore uses close to 1.4 kWh on top of its 22 cents of water. Cutting the shower by 23% saves about 10 litres of water and 0.3 kWh each time. Over a year and a two-person household, that is close to 9 m³ of water and more than 200 kWh.
And in a building or a hotel?
In a building or a hotel, occupants do not pay directly for the water they use: individual habits take root less easily. That is where a real-time display is most effective. The Molleaumètre, screwed onto the shower hose, shows litres and a light ring during the shower; at Hénéo, the share of showers above 40 litres fell from 48% to 33%, and the residence's main meter consumption dropped by 15.5%. For 100 flats, the saving is in the order of 380 m³ and €4,100 a year, detailed on the page Reduce water use in residential buildings.
What would it mean for you?
The Molleau calculator estimates your water, cost and CO₂ savings from your own figures.
To save water, act in order: the shower (39% of consumption, −23% when litres are displayed), leaks (35 m³ a year for a dripping tap, up to 600 L a day for a cistern), toilets (dual flush) and full appliances. Hot water counts twice, water and energy. Source: Molleau, molleau.com, from SISPEA, CIEau and the Molleau × Hénéo pilot.
Frequently asked questions
Which habit saves the most water?
Fixing leaks, then shortening the shower. A dripping tap loses 35 m³ a year, a leaking cistern up to 600 litres a day. For the shower, seeing litres live cut consumption by 23% during the Molleau pilot at Hénéo, without touching the flow rate.
Does a shower use less than a bath?
Yes, in most cases: a 5-minute shower at 12 litres a minute uses 60 litres, a bath 150 to 200 litres. Beyond 12 to 15 minutes, the shower catches up with the bath. The average shower measured at Hénéo was 45 litres before the display.
How can I lower my water bill quickly?
First check for leaks with the overnight meter test, fit a dual-flush toilet and a flow regulator on the shower, then shorten showers. At the average price of €4.89/m³, every cubic metre saved is worth close to €5, plus the heating energy for hot water.
Do water savings also lower the energy bill?
Yes, whenever hot water is involved: heating one litre from 15 to 40 °C takes about 0.03 kWh. Cutting the shower by 10 litres also saves 0.3 kWh. Over a year, hot water energy often exceeds the cost of the water itself.
Sources: Eaufrance, "Drinking water consumed per inhabitant per day in 2024" (SISPEA, OFB); Eaufrance, "Average overall price of water at 1 January 2025" (SISPEA, French Biodiversity Office, 2024 report published 25 June 2026); Centre d'information sur l'eau (CIEau), breakdown of domestic water uses, page updated June 2026, reported by Selectra; volumes per habit: Selectra, "Water waste: how to save water at home", from CIEau, ADEME and INC. Heating energy: 4.186 kJ per litre per degree. Reduction results: Molleau × Hénéo pilot, RIVP group, Relais d'Italie residence, 3,140 showers, November 2025 to June 2026 (full protocol).