Decalogue for reducing water consumption within cities and municipalities

The last few years of below-average rainfall have changed the public’s view of water. Drought, and thus the protection of water resources is becoming the number one issue in public and political space. Based on our experience in building certification, energy monitoring including water, building technology and construction experience, we have decided to publish 10 technical-management rules that will help reduce consumption within cities and municipalities. Decalogue to reduce water consumption.

Tipy pro úsporu vody ve městech a obcích

1. Monitor your consumption at least on a monthly basis and establish benchmarks for comparison

It is absolutely essential to have a basic overview of the consumption of individual buildings and of all buildings in the whole. Determine basic ratios, such as consumption per m2 of floor space or consumption per person, so that you can make meaningful comparisons between buildings. It not only compares individual calendar months, but also year-on-year comparison. Set your consumption limits and take action immediately. If you use automatic water meter reading, you can afford to detect wastage literally in real time. We recommend setting a flow detection alert between 00:00 and 4:00 in the morning. This is the time when the flow in the buildings is always minimal and therefore the ideal time to detect unwanted consumption that you would not detect in another hour. When automatically collecting data from water meters, it is advisable to set alerts for weekend consumption as well.

In our Enectiva app, you can monitor every water meter online at a cost of $ 2.00 / month, including the ability to set your own over-consumption alert.

The principles of water measurement can be read in our article from 2016 here: https://www.enectiva.cz/en/blog/2016/02/mereni-spotreby-vody/

2. Invoice water according to actual consumption

In the case of renting municipal residential or non-residential premises, it is always necessary to invoice the water consumption according to the actual design on the secondary water meters. This is the only way to get the right motivation for tenants to behave in a gentle way. Water meters must be properly metrologically verified. Gauge is valid for hot and cold water for 5 years. Where subsidiary water meters are missing, have them completed as soon as possible. Energy billing to tenants can be fully automated, so it does not mean a higher administrative burden.

There are countless types and manufacturers on the market. To choose the right water meter, it is good to contact the designer or a professional company that deals with water meters and their installation. We can also help if you have any questions.

3. Keep maximum rainwater

We are the roof of Europe. The location of our country, where the vast majority of rivers in our country springs and then flows into the surrounding countries, makes us destined to use maximum rainwater. It is the only one we have. It is necessary to learn to retain water, either in the landscape or in artificial reservoirs.

  • encourage residents to buy rainwater tanks

  • Use suitable paving and finishes for water-permeable surfaces, not just drainage

  • For buildings, use special roof systems that use rainwater:

Green roof = roof that is covered with soil and vegetation. Rainwater soaks up the runoff and creates a unique environment for vegetation, but also for animals (eg birds). In recent years, greenery on buildings has been an effective solution in urban adaptation strategies for climate change

Blue roof = The blue roof is purely used to retain rainwater. Although we do not know any project in the Czech Republic that can be considered a blue roof, but in foreign countries, where there are problems with water are becoming a trend. (We recommend searching for “Blue roof”. Water instead of drain can be used to run the building. There are countless ways to use rainwater - watering, washing dishes and laundry (rainwater is ideal because it contains almost no minerals, therefore, it does not cause lime scale), toilet flushing, and other cleaning processes to save water and sewage rates at the same time.

Green-blue roof = As the name suggests, it is a system that combines the advantages of both roofs mentioned above. It is one of the most efficient and aesthetic roof systems.

4. Proper flow on end elements and outlets

In the case of energy audits, we also standardly check the flow rates at the end elements and it is quite common that in the case of standard washbasins in WCs the flow rates are around 15 l / min.

The flow rate ::

  • 2 l / min for hand washing

  • 4 l / min for sinks

  • 6 - 8 l / min for showers

Check the flow rates, just measure the canister and stopwatch and every member of the maintenance can do it. Have a flow audit performed and then install either aerators or fittings with less flow where the flow needs to be adjusted. For toilets, it is obviously necessary to use a two-stage flushing. For old tanks (which used up to 12 liters per flush) it is possible to add a so-called stop flush or a bag filled with different mass. Both aim to reduce the volume of flushing water. Also, regular checking that the flushing system is sealing and that the water does not flow into the bowl is suitable.

5. Consider water consumption when purchasing new technologies

In all tenders or purchases of technologies related to water consumption, consider consumption intensity as one of the selection criteria. The cities that implement ISO 50001, ie the standard for energy management, have become accustomed to incorporating energy efficiency as one of the parameters in technology selection. Do the same with water and technologies that affect water consumption. Toilets, dishwashers, faucets, but also need air humidifiers, machine cooling, etc.

6. Instruct the responsible person to monitor consumption, report statistics, check and address corrective actions

Every activity is always about the people who do it. If you define a clear responsibility to someone in the community team, the implementation of individual water saving measures will go much smoother. The municipal “water sprite” must have both the competence and the right motivation to seek new opportunities. Water must become the subject of regular city management meetings at least once a quarter. Provide consumption reports, trends, comparisons with the previous year, plans of action and a list of activities that have an impact on water consumption.

7. During new construction and reconstruction of urban buildings, pay attention to the infiltration area

Rainwater drainage has to be solved with regard to the previous situation when its volume does not increase. The water that is drained into the sewage system is minimized and, on the contrary, its leakage must be encouraged. Various variants of natural drainage systems (SuDS - Sustainable Drainage Systems) are intended for this purpose.

Retaining water in the landscape and not draining it into the sewage system is desirable, not only because you save money on sewerage. It is advisable to use surfaces with the lowest drainage coefficient in the vicinity of buildings (= coefficient determining how much water is not absorbed and drains into the sewer).

For this purpose, the areas are divided into 3 categories:

  • A: built-up and hardly permeable paved areas: buildings, asphalt or concrete surfaces, jointed tiles, etc., drainage coefficient = 0,9
  • B: slightly permeable paved areas: means unpaired or quarry paving, gravel surfaces, originally unpaved areas permanently used for walking or moving vehicles, etc., drainage coefficient = 0,4
  • C: areas covered by vegetation, drainage coefficient = 0.05

For new projects, require rainwater runoff calculation for the pre- and post-construction situation. The difference must ideally be in favor of the condition after, in terms of the amount of water soaked.

8.Reduce the pressure in the water distribution system to its optimum level

Higher pressure means higher losses but also higher wear of all elements, more frequent breakdowns and higher operating costs (pumping). Require a water pipeline master plan to address pressure zone optimization. The optimum pressure should be in the range of 0.15-0.60 MPa and there should be as little difference between the peak (morning and evening) and the time with minimum consumption (00:00 - 4:00).

We recommend having a water loss audit performed at the outset to give an overview of how your water distribution system works.

A Czech company dealing with general plans and hydroinformatics of towns and villages is eg http://www.aquecon.cz/

9. Plant greenery that can handle even drier conditions and is not water-intensive

The most dry plants include fig tree (watering 1 - 2x during the summer months), evergreen trees such as cedar, oak or pine (they prefer a very small amount of water), cypresses (which also absorb noise), aloe vera (watering only if the soil is completely dry), cactus (needs almost no water), as well as mulberry, clusters of ovoid, mother-in-law’s tongue, roots, ginkgo biloba, puchol or burrow. Of all vegetation, the most demanding lawns are water. In the event that you have planted some lawns, set the irrigators to consume a maximum of 20 - 30 liters per square meter of grass per month. Ideally, plant a tree near the lawn to shield it and reduce water consumption even further. As for trees, they need less frequent but more intensive irrigation, so that the soil is irrigated in depth. It averages 100 l per month. For more information on plant water consumption, visit the following pages:

10. Educate the public about water savings

Each of us, and therefore every user of the building and every inhabitant of a municipality or city, can contribute to more environmentally friendly water management. Water management is largely about people, so it is important that there is awareness raising that encourages people to be responsible for water management, eg through marketing campaigns (flyers, videos), the information in the municipal press, engaging children in schools through games, building-to-building competition to be more effective. Social networks have many negative aspects, but they are great for spreading information among people. Use municipal Facebook or Instagram to educate on water saving.

Water technology is constantly evolving, and scientists are constantly bringing new ideas for water management. Of course, we carefully monitor them for you, but we do not know everything, so we will be glad for your feedback. Would you choose another 10 rules? We will be glad for your experience.