Planning and design

How to save water in the bathroom: toilet, aerators, shower and leaks

The most water in the bathroom is consumed by the WC, shower, and bath. You will save by using the small flush and ensuring the WC has the correct volume set, by having mixers with water-saving aerators, for example, set to 5 or 7 litres per minute, and by showering instead of bathing. The most expensive are hidden leaks – leaking WCs and dripping mixers.

Prepared by: the TGB Kúpeľne team, bathroom showroom in Senec since 1991updated 8. 11. 20266 min read

Saving water in the bathroom does not mean showering with cold water or not flushing. Most savings come from how the bathroom is equipped and set up: how much water the WC releases, how much flows through the mixer per minute, and whether water is leaking somewhere. Many measures cost little and can be done immediately, while others are worth considering during renovation.

Where water is leaking in the bathroom and what helps

Toilet: small flush and correct volume

Concealed cisterns have two buttons – large and small flush. The volume can be adjusted. For example, with the Geberit Duofix with a Sigma 12 cm cistern, it is factory set to 6 and 3 litres, and the large flush can be adjusted to 4, 4.5, 6 or 7.5 litres, while the small flush ranges from 2 to 4 litres. The Alcadrain ECOLOGY and Deante ECO modules flush 4 and 2 litres.

However, the smaller volume must match the bowl – the bowl must be designed for the specified flush volume, otherwise it won't flush properly and the saved water will be used for a second flush. Therefore, the volume is set by the installer according to the manufacturer's instructions for both the cistern and the bowl. More about the modules in the article Wall-hung toilet: what you need to know about the concealed cistern frame.

Aerators: the cheapest savings

An aerator is a small attachment on the tap outlet that mixes air into the flow. A water-saving aerator also limits the flow. For example, water-saving aerators from Neoperl are made with a flow of 5 or 7 litres per minute at a pressure of 3 bars. The flow feels full, and you can wash your hands just the same. The aerator can be easily unscrewed – the common threads are M22 and M24, so check which one your tap has before purchasing.

A water-saving aerator is not suitable for a non-pressurised (open) water heater, such as a small tank under the sink – use what the heater manufacturer specifies. Clean the aerator from limescale from time to time, otherwise the flow weakens and splashes – the procedure is described in the article Limescale on the tap.

Shower instead of bath

A full bath uses more water than a regular shower. If you only bathe occasionally, you'll save most of the water just by showering. How to replace a bath with a shower is described in the article Replacing a bath with a shower enclosure. When showering, consider:

• water-saving shower head or flow restrictor insert for handheld showers – they are made, for example, for 7 litres per minute,
• turning off the water while soaping – just a lever or button on the head is enough,
• reasonable size of the head – a large rain head requires more water for an even flow, the differences are explained in the article Shower heads and handheld showers.

Water-saving taps

• Thermostatic mixer – set the temperature once and the water is immediately at the right temperature, it doesn't run unnecessarily while searching for the temperature. The safety lock at 38 °C protects against scalding.
• Sensor tap – water flows only while your hands are under the outlet. More in the article Sensor tap.
• Single-lever mixer – some models only release cold water in the middle position of the lever, so it doesn't unnecessarily activate the heating. The data is provided by the manufacturer for each specific tap.

Hidden leaks: the most expensive water

A leaking toilet and dripping tap waste water day and night. If you hear a quiet hissing in the cistern or see a thin stream of water in the bowl, the fill or flush valve is not sealing. The repair is described in the article The toilet is leaking, and the dripping tap in the article Dripping tap.

Simple check: in the evening, note the water meter reading and check it in the morning before anyone uses water. If the number has changed, water is leaking somewhere.

Hot water: save both water and energy

While hot water flows from the tap, cold water that has been sitting in the pipes drains away. The closer the heater is to the bathroom and the shorter and insulated the pipes are, the less water drains away unnecessarily. Address this with the installer right at the beginning of the renovation. By saving hot water, you also save energy for heating.

Savings during renovation

• concealed cistern frame with adjustable volume and a bowl designed for it,
• thermostatic mixer for shower and bath,
• taps with water-saving aerator or flow restrictor,
• shower instead of bath if you bathe infrequently,
• short and insulated hot water pipes.

If you have a septic tank or are at a cottage, saving water is even more important – see the article Bathroom at the cottage and summer house. Automatic functions like sensors and hygrostats are described in the article Smart bathroom. You can see taps, showers, and control buttons in person at the store in Senec at Bratislavská 71. On the e-shop vkupelni.sk you will find aerators, WC control buttons, and fill and drain valves. Changes to the plumbing and setting up the cistern are done by the installer.

Most common misconceptions about saving water

• "A smaller flush volume always saves." Only if the bowl is sufficient for that volume. Otherwise, you'll flush twice.
• "An aerator just splashes." A clogged aerator splashes. A cleaned water-saving aerator gives a full and soft flow.
• "Dripping is negligible." Drop by drop it runs all day and night – don't postpone the repair.
• "A large head is more economical." A large rain head actually requires more water for an even flow.

Sources: Geberit – catalog sheet Duofix with Sigma 12 cm (factory flush volumes and adjustment ranges), Alcadrain – technical sheet Sádromodul ECOLOGY (2/4 l), Deante – concealed module ECO 4/2 l according to vkupelni.sk, Neoperl – water-saving aerators and shower inserts (flow at 3 bars, unsuitable for non-pressurised heaters), our articles Shower mixer (38 °C safety lock) and Sensor tap (November 2026).

Terms in the glossary: Aerator · Thermostatic mixer · Installation (concealed) module · Wall-hung toilet · Fill and drain valve · Hygrostat