Together with our customers, we work on making the water consumption in their buildings more efficient. Sometimes there are small practical steps that can add up to big savings. We can advise you on this. In this article, we look at a specific example of a building to show what that advice might look like.

The building we looked at is located in the Netherlands. It's an apartment building with 24 flats for people living in assisted living. Each resident has its own kitchen and bathroom. There are also several common rooms and two offices in the facility.

To estimate how a location is doing, we use our own Water Efficiency Index (WEI). We developed this WEI to provide insight into how water efficient a building is compared to similar buildings. You're awarded points between 0 and 100. This location has a WEI score of 10.

According to the CBS (Statistics Netherlands), the average Dutch person uses approximately 134 liters of water per day. Based on this, we expect that these residents together consume about 1.222.750 litres per year. This is 1222 m³.

The data shows that consumption was approximately 65% more than expected. We looked at the consumption per day and per month. We see that the consumption is relatively constant, and that there are no major outliers in consumption that would explain this annual consumption. The focus of the advice is therefore on adjustments that reduce normal consumption. It is worth bearing in mind that this is an apartment complex with a specific use. The users of this complex are probably at home more than the average flat dweller.

We have conducted a number of spot checks to gather input. The focus is on the following three types of water points: taps, toilets, and showers. All recommendations are aimed at saving water without compromising on comfort.

**Advice on taps **

Our advice is to replace the aerators on all taps. This is a filter that can be detached from the tap. Water-saving aerators allow more air to pass through, which means that less water is used during the use of the tap. Of course, you can't save on all consumption. A bucket with a liter of water is still a liter of water. Aerators can save at least 30% of the tap water. This would be 3% of the total consumption. That is 62 m³ per year.

**Cost of replacing aerators **

These aerators cost an average of €5,50 a piece (excluding installation). The investment for 58 taps thus comes to €319. At a water cost price of €1,05 per m³, the payback period is 4.9 years (based on minimum savings of 62 m³ per year). The aerators last at least 10 years. The installation is easy and quick.

**Advice on showers **

The existing showers use between 10 and 13 liters per minute. An average shower takes 9 minutes, or 90-117 liters per shower. There is potential to save a lot here by replacing the showerheads.

A water saving showerhead consumes 5,7 liters per minute on average. Compared to the current situation, this would therefore save 33-60 liters per shower. If on average, the residents take a shower once a day, this easily results in annual savings of 350 m³.

**Replacing showerheads **

Replacing the showerheads would cost around €607 in terms of materials. The payback period, at current water prices, is around 1,65 years. This does not include installation. Please note that it is sometimes recommended to replace the shower hose as well.

**Advice on toilets**

We were unable to perform an accurate measurement because this location has in-wall flush toilets. Therefore, we made an estimation based on the data in the Smartvatten portal. The Geberit dual-flush button that is currently on the toilet does allow for the use of less water through the small flush button. However, further savings could still be made in the form of maintenance scheduled for the next five years. If the toilets are serviced quickly, this could save some 3 to 5 liters per flush. However, we do not consider this to be cost-effective in this situation.

**Conclusion **

With an investment of less than €1000 in material, annual savings of 412 m³ can be achieved. This is 20% of the current water consumption. The installation of these water saving measures can be done within 1 working day by someone from your own facility service. We expect the Water Efficiency Index score to go from 10/100 to 35 or 40/100.

Based on our CO2 emission calculations, this location could achieve a 40% reduction on an annual basis. As the water saving measures focus on the shower heads, this also means a significant reduction in the use of hot water. This in turn results in a lower energy bill. This is extremely relevant at the moment, given the high energy prices.