A connected water meter for the shower measures litres as they flow, displays them in front of the person showering and sends the data to an app or a dashboard. Unlike a main meter, it acts during consumption: in the Molleau pilot run with Hénéo on 3,140 showers, consumption fell by 23% per shower, from 45 to 34.7 litres, with no flow restrictor and no loss of comfort.
How does a connected shower water meter work?
A connected shower water meter screws onto the hose, between the mixer tap and the shower head. A micro-turbine measures the flow and powers the device, with no battery. A screen shows the litres used since the start of the shower and a light ring changes colour with the volume: green below 20 litres, orange from 20 to 40 litres, red beyond. Data travel by Bluetooth to a gateway, then to a dashboard and, for the user, to an app with no download, reached by QR code.
That is the principle of the Molleaumètre, designed by Molleau and protected by a patent filed in 2025. The flow rate is never reduced: the drop in consumption comes from behaviour, not constraint.
Why does displaying litres during the shower lower consumption?
Displaying litres during the shower makes visible a consumption nobody perceives: hot water runs, the meter is in the basement, the bill arrives months later. A number and a colour, at the moment of the action, are enough to decide. Behavioural science calls this a "boost": giving clear information rather than constraining. At Hénéo, the share of showers above 40 litres fell from 48% to 33%, and of showers above 60 litres from 23% to 14%. In hotels, the University of Surrey (Journal of Travel Research, 2024) measured showers up to 25.8% shorter with a real-time display, over more than 17,500 showers in the United Kingdom, Denmark and Spain.
How is it different from a water-saving shower head or a flow restrictor?
A water-saving head or a flow restrictor acts on flow rate: it cuts litres per minute, sometimes at the expense of comfort, and changes nothing about the length of the shower. A shower meter acts on duration and attention, leaving the flow intact. The two add up. The difference also shows in how long the effects last: the Molleau pilot showed no habituation effect over eight months.
| Solution | Acts on | Comfort | Measurement and data |
|---|---|---|---|
| Flow restrictor, aerator | Flow rate (L/min) | Perceived pressure sometimes reduced | None |
| Shower head with coloured LEDs | Attention | Unchanged | Colour only, no litres and no data |
| Connected shower water meter (Molleaumètre) | Duration and attention | Unchanged, flow preserved | Litres displayed, dashboard, app |
Who is a connected shower water meter for?
It is made for places where the person showering does not pay for the water: hotels, student residences, social housing with collective charges, hostels, boarding schools. The manager sees every room on a dashboard, exports savings in litres, euros and CO₂, and has data for labels and reports. For a hotel, the saving is about €141 per room per year on shower water, for a subscription of about €72 a year; details are on the Hotels page. For a landlord, the page Reduce water use in residential buildings gives the projection for 100 flats.
How is it installed?
It is installed with no building work: the Molleaumètre screws onto the shower hose, as simply as a shower head, room by room, with no water shut-off and no heavy tools. It has no battery to change and is cleaned like the rest of the shower. The Molleau team fits the devices and the gateways, then briefs the staff; the dashboard is available from day one. Recessed ceiling showers cannot be equipped.
What would it mean for your rooms?
30 minutes to estimate your property's savings potential. No commitment.
A connected water meter for the shower displays litres while the water runs and sends the data to a dashboard. It acts on shower duration, not on flow rate. Result measured by Molleau at Hénéo on 3,140 showers: −23% per shower, from 45 to 34.7 litres, −15.5% at the main meter, 5/5 satisfaction. Source: Molleau, molleau.com.
Frequently asked questions
Does a shower water meter need batteries?
Not the Molleaumètre: a micro-turbine driven by the water powers the screen, the light ring and the transmission. It works from 4.5 litres a minute. Other devices on the market run on batteries.
Does a shower meter reduce pressure?
No. The Molleaumètre contains neither aerator nor flow restrictor: pressure and flow stay identical. The drop in consumption, 23% on average in the Hénéo pilot, comes from the display alone.
Do you need an app to use a connected shower meter?
No. The Molleaumètre shows litres and colour directly in the shower. The app, reached by QR code with no download, is a complement to follow your showers, join challenges and earn rewards.
Where is a connected shower meter most useful?
Where the occupant does not pay for their water: hotels, student residences, social housing with collective charges. The manager follows every shower on a dashboard and has quantified data for labels and CSR reports.
Sources: Molleau × Hénéo pilot, RIVP group, Relais d'Italie residence, 28 flats, 3,140 showers, November 2025 to June 2026 (protocol and results); University of Surrey, Journal of Travel Research, 2024 (more than 17,500 hotel showers, showers up to 25.8% shorter); Centre d'information sur l'eau (CIEau), breakdown of domestic water uses, page updated June 2026, reported by Selectra.