Now is the time when even in the Czech Republic we have to save water. In our households we can use grey water for flushing toilets, used water reuse for irrigation, etc. But we must not forget the risks associated with gray water re-use.

The change of Z1 ČSN 75 5411 was mainly processed due to the incorporation of water meter shaft requirements without the need to enter persons (so-called microshaft) into this standard. The current version of ČSN 75 5411 of April 2006 did not mention the water meter shaft without the necessity of entry of persons, and there were doubts as to whether such water meter shafts on the water connections are permissible.

At the time of changing climatic conditions and reducing the quantity of raw material it is necessary to start saving water and raw materials. To achieve this target it is good to separate wastewater at the source and using of no-mix toilets. Czech legislation is not yet adapted to this alternative treatment of waste water.

The paper is focused on the issue of the pipeline networks dilatation. From the perspective of the designer, it is a very simple and well-documented issue. However, as is shown in the article, if the basic requirements are not met when designing the pipeline networks, the results can be quite fatal.

The unused chimney flue or strong wall of the chimney body offers the possibility of using it for conducting pipes etc. It is a prerequisite to keep the flue gas safety and operating mode of other installations. The article highlights the important factors of a possible decision.

The definition of what is a common part of a residential building is essential especially when modifying the building structures and eliminating defects that affect both a common part and residential units. How common parts are defined affects who finances the modifications and reconstructions of such structures and parts. The definition of common parts is based on the new Civil Code (No. 89/2012 Coll.) and on the already abolished Act on Ownership of Housing (No. 72/1994 Coll.).

The article presents a concrete example of a real operational problem with the use of so-called double-walled hot water heaters resulting from the heat-technical properties of such water heaters.

The parameters and characteristics obtained from the laboratory test are used to compare products in terms of performance and efficiency. The results also serve for the correct design and evaluation of the year-round behavior of the element built into the entire thermal system.

The article deals with the definition of consumer and basic heating rate. It is recommended to use the ratio of 50 % basic nad 50 % consumer rate or 60 % consumer and 40 % basic if individual heat meters are used.

For individual payment calculation for hot water we need an invoice from heat supplier with the total cost of the property in CZK and with the amount of GJ. In addition, we need the water supplier invoice, which includes the total cost of water and sewerage. For the calculation then we need water consumption from water meters.

Paper presents the analysis of water heating by a heat pump and influence of tank size, temperature setting and heat pump selection on annual use of electric energy.

The article deals with the issue of safety valves installation for water heaters. Neglecting of the installation conditions often causes damage to the installed appliance, or (as shown in the paper) loss on the water and sewer charges in the case of a safety valve installed in the water heater safety group.

The article summarizes overview of ways to secure water heaters in Europe, which became the basis for design of integrated methodology applied in the Czech Republic.

Sulfate attack is one of the major threats for durability of concrete in sewage collection systems where concrete sewer pipes are exposed to sulfates from waste water as well as from biogenic activity of bacteria. Damage due to sulfate interaction can result in the cracking and softening with loss of strength of concrete and it may lead to the concrete desintegration. Gypsum is the primary product of sulfate attack on concrete, after which ettringite is subsequently formed. Ettringite and gypsum are considerably larger in volume than the initial compounds, which leads to increased pressure within the concrete structure. This paper is focused on the sulfate attack on fine-grained concrete where the effect of 12 months contact of 0.5% sulfuric acid, simulating biogenic sulfuric acid corrosion, 5% sodium sulfate solution and solution simulating sewage water on various types of concrete has been investigated. The concrete specimens were characterized after exposition to the corroding media by their mechanical parameters, changes in pH and content of sulfates. It was found that after one-year exposure to sulfuric acid solution, the compressive strengths of all types of concrete significantly decreased. Sodium sulfate solution and the artificial waste water did not represent the significant corrosion environments for the concretes in terms of their strength reduction, increasing of sulfate ions content and the reduction in the pH of their aqueous leaches. The fine-grained concretes containing metakaolin and ground limestone showed the highest coefficient of corrosion resistance for the applied corrosive solutions.

The article deals in detail with the solar water heater from the EU Commission Regulation 812/2013. It describes what information provides the label and how it originated classification in the relevant energy efficiency class water heating.

The paper gives a simple method for calculating the annual production of condensate in the condensing boiler.

This article summarizes the basic concepts of Commission Regulation EU 811/2013 and 812/2013, focusing on solar equipment, solar water heaters and solar packages. Describes the responsibilities of suppliers who place such products on the market.

Rainwater is largely perceived as a waste water in Slovakia and in the Czech Republic, which should be divert as soon as possible to the sewage system. For many years it was mostly only one way of drainage of buildings and paved surfaces generally called “conventional way” of drainage. This paper describes the possibility of using rainwater in the school building, on the basis of the measured volume of rainwater runoff draining from the roof construction. The data were compared with the theoretical values of the water needs for the building.

This paper describes measured data and evaluation of water consumption in a family house, where secondary source of water was introduced - water from a well. Potable water was fully replaced by well water for the purpose of flushing toilets and laundry . This paper also describes the measurement data of stormwater runoff from the roof of the school building as a potential alternative water source for this building. Next step was the comparison of the current potable water consumption in the building with inflowed rainwater and evaluation of its potential for supplying the object in case of accumulation of this water.