8 types of water filters


Water from a centralized water supply is subjected to purification before use in order to remove impurities, heavy metals and microorganisms. Filters are used for this procedure.

Filter jugs


The filter jug ​​consists of 3 elements:

  • a jug with a lid;
  • receiving bowl – funnel;
  • cartridge.

A jug is a transparent plastic container of 1.5-4 liters with a traced volume scale. Some models are equipped with lids with valves, which prevents dust and microorganisms from entering when filling the bowl.

Half of the jug is occupied by a funnel, at the bottom of which there is a cleaning cartridge. The volume of the funnel also varies; to clean the full volume of the jug, water is drawn into the funnel twice.

Depending on the model and manufacturer, the cartridge resource is designed to clean 170-450 liters, then it must be replaced with a new one.

Some cartridges are equipped with a counter of the processed liquid, which allows you to make timely replacement. The filtration rate at the beginning of operation is 35 liters per hour, as it is used, it slows down.
For cleaning, the cartridge includes the following layers:

  • activated carbon interspersed removes chlorine and blocks the development of microorganisms in the purified liquid;
  • ion-exchange resin softens water and reduces mineralization, retaining magnesium, calcium, iron;
  • porous activated carbon improves taste, color and smell by removing organic compounds;
  • polypropylene fiber retains mechanical impurities inside the cartridge.

The quality of purified water using a jug varies and depends on the hardness of the incoming liquid and the duration of use of the cartridge. The advantage of such filters is their low cost, this is a budget option.

They are designed for use in a house where 1-3 people live. If the number of family members is larger, then frequent cartridge changes will increase cleaning costs. Pitchers are easy to use, easy to transport, so they are used both at home and in summer cottages.

The low degree of purification in comparison with other filtration systems and the frequent replacement of cartridges are the main disadvantages of this method.

Prolonged use of a cartridge without replacement leads to a deterioration in taste and regulatory characteristics.

Coarse filters


Coarse filters are installed on pipes to remove large insoluble particles from the liquid. It is relevant to use such devices for country houses, where water comes directly from a well, then they retain dirt, sand, clay, and organic compounds. The apartments are operated for the purpose of cleaning from rust, limescale, scale.

All coarse filters with the same principle of operation. The cleaning process is simple: water passes through a mesh that prevents the passage of particles larger than the cells. Depending on the model, the body material (metal, polypropylene), installation and internal contents vary.
There are the following types:

  • mesh and cartridge;
  • flange and coupling;
  • straight and oblique;
  • non-flushing and flushing.

The most common option is a mesh filter, in which a stainless mesh with cells of 50-400 microns is installed. The filter element is replaced if it is damaged; the warranty period for such models is 30 years. The competing type is a cartridge filter with a transparent flask, in which a replaceable element made of polypropylene fibers or threads is installed.

Flanged devices are installed on pipes with a diameter of more than 2 inches, otherwise coupling devices are used.

Filters of direct or oblique type are distinguished by the presence of inlet and outlet pipes and a tank in which purification takes place. In the direct type model, the tank is located perpendicular to the ceiling, in the oblique type – at an angle to the incoming flow. The use of devices of this design improves the filtration process due to the settling of large particles in the tank, and small ones on the grid.

Non-flushing models include oblique, some straight and cartridge filters. To remove the accumulated dirt, a special cover is unscrewed, the mesh is taken out and washed, then placed back. Cartridge models are not cleaned, the internal element is regularly changed to a new one.

Washing devices are equipped with an additional outlet valve, through which the accumulated dirt is washed off by means of a direct and reverse flow of water. Washing models include direct filters.

The installation of models of the direct type of coarse cleaning is carried out only on horizontal pipe sections so that the tank is directed downwards. Oblique models can be installed both on horizontal and vertical sections of the pipeline (if the water moves from top to bottom).

The direction of water movement is indicated by an arrow on the body, the sump must be located below. It is recommended to mount coarse cleaning devices before the counters.



Pre-filters are designed to remove large particles, sand and rust. Such devices are designed for mechanical cleaning and do not remove heavy metals, chlorine and microorganisms from the liquid.

Pre-treatment of water before it is fed into washing machines, dishwashers, heating and plumbing appliances is the main task of this type of filters.
Installation of devices takes place in cold and hot pipelines after the shut-off valve, but before the meters. Installed inside:

  • a metal mesh with small cells, which traps particles from 30-50 microns;
  • cartridge with non-woven material – polypropylene, which retains debris over 5-20 microns.

Metal grids are removed every 1-2 months, the accumulated particles of rust, sand are washed and set in place. Additionally, some models are equipped with a mesh flushing system, which does not require the dismantling of the device with water shutoff, there is also an automatic flushing of the mesh from contamination with discharge into the sewer.

Certain models are equipped with fluid pressure control valves. Pressure gauges – pressure measuring devices in such models are installed before and after the filter, while an underestimated indicator after the device indicates the need to flush the mesh. The dimensions of the device correspond to the diameter of the pipes.

Devices in which cartridges are installed carry out not only mechanical cleaning, but also chemical. If replaceable capsules are installed that contain coal, ion exchange resins, silver.

There are a number of requirements for installing pre-cleaners:

  • appropriate performance according to the flow;
  • with heavily polluted water, metal meshes are installed, with relatively clean water – with cartridges;
  • installation is carried out by a qualified person.

Pre-filters are installed if a fine filter device with fine mesh membranes is planned or already installed. Since the ingress of large particles into the membranes clogs the cells, and the cartridges are often changed.
The advantages of installing a pre-treatment system are:

  • removes large insoluble particles from the flow;
  • devices with a metal mesh do not require regular replacement, are easy to clean, which reduces maintenance costs;
  • small dimensions;
  • simple design;
  • increase the duration of the operation of devices that consume water.

Removing only large particles of debris from the water is the main disadvantage of pre-cleaners.

Main filters


A filter that is directly connected to a water pipe is called a main filter. It consists of a steel or plastic collapsible flask, inside of which a cleaning element is installed.

The throughput is 20-50 liters per minute. Depending on the installed replaceable cartridge, the main devices purify the liquid from large particles, impurities, chlorine, improve the taste and soften it.
The correct choice of the main filter is based on the following parameters:

  • line type;
  • degree of purification;
  • type of shell;
  • cartridge type;
  • performance;
  • hydraulic losses.

Install such models on pipes with hot and cold water supply, paying attention to the temperature characteristics. Devices for hot water can be installed on both cold and hot pipelines.
Main filters perform several degrees of purification.

  • Single-stage models remove sand, rust and fine debris.
  • Two-stage carry out cleaning of the first and degree, and also remove chlorine, organics and unpleasant odors.
  • Three-stage models, in addition to the previous 2 stages, soften water and remove iron.

When choosing a main filter, a preliminary analysis of the incoming liquid is carried out, since there is no universal cartridge. They vary depending on the problem:

  • BS for hard water;
  • BA for iron removal;
  • activated carbon to remove chlorine;
  • polyphosphate for purification from magnesium and calcium.

Depending on the cartridge, the following types are distinguished:

  • mesh;
  • corrugated;
  • propylene;
  • winding.

The main devices with a mesh cartridge carry out only rough cleaning of the liquid. For fine purification, so that the water is suitable for consumption, it is necessary to install other replaceable elements.

If the water flow in the house is insignificant, then the body is taken with a diameter of 114-130 mm (SL), otherwise, bodies with a diameter of 184 mm (BB) are designed for medium and high flow.

The number of storeys of the location of the apartment also affects the choice. The higher the floor, the lower the hydraulic loss should be, which varies in the range of 0.1-0.6 bar.

The main filter with a granular load is used for the complex elimination of chemical and biological contaminants, and it also acts as a water softener. The filtering layer is filled with grains of quartz sand, expanded clay, rocks, polymers, anthracite, marble chips of various sizes.

Iron filters


To install a filter for cleaning from iron, a water analysis is first performed and the presence of iron ions, pH value, alkalinity, oxygen content are determined. Iron, as the most common metal, can be in liquid in 4 states:

  • colloidal;
  • bivalent;
  • trivalent;
  • bacterial.

After the passage of water along the central highways, ferrous and trivalent iron are found as impurities. A coarse filter, as well as an ultrafilter with garbage disposal and backwashing of membranes, copes with the purification of ferric iron.

Ferrous iron is removed from the water using an ion exchange filter and a reverse osmosis system. The ion exchange filter contains cation exchange resin and calcite. These elements replace iron with sodium. The liquid, passing through them, is cleared of iron, chromium and strontium.

Ion exchange devices are effective when the iron content does not exceed 2 mg/l. In the process of purification, ferrous iron is converted into trivalent. Its large particles clog the pores of the resin, making it unsuitable for further cleaning. To maintain the filtration quality, replace the cartridge regularly.

Reverse osmosis filters are considered an effective system for removing iron from a liquid. The membrane installed in such a system does not allow iron ions to pass through.

This is because the iron ions are larger than the membrane cells. The garbage sorted by the system is drained into the sewer without clogging the cells and without stopping the operation of the device. At a pH of 7, the system purifies water with an iron content of up to 20 mg/l, at pH values

Reverse osmosis filters


Reverse osmosis systems are devices whose water is 99% purified from impurities. Due to the presence of a multi-stage liquid purification system, the output is water, similar in its parameters to bottled water.
The filter process consists of the following steps:

  • preliminary cleaning;
  • passage through the membrane;
  • tank filling;
  • supply of purified water to the faucet.

The pre-cleaning stage consists in removing large particles and chlorine from the liquid, which have a detrimental effect on the condition of the membrane.

In order not to change the membrane due to breaks and contamination, 3 flasks are pre-installed.

The first flask-prefilter is intended for mechanical purification of liquid from sand, dirt, rust with sizes over 5 microns. The second flask is based on granular activated carbon, which delays the further passage of chlorine and organic compounds. The third flask is a mechanical prefilter with an inlet diameter of up to 1 micron, the function of which is to delay and remove residual contaminants.

The second stage of purification is the passage of liquid through the membrane. The membrane is a porous synthetic material twisted into a roll. The pore size is 0.0001 microns.

It is this characteristic of the membrane that makes it possible to pass through the material only molecules of water and its constituent gases (oxygen, hydrogen). All other connections exceeding the size of 0.0001 microns are discharged through the drainage outlet into the sewer by a forced flow of fluid.

The performance of household reverse osmosis systems varies in the range of 150-300 liters per day. Purified water enters a storage tank of 4-12 liters, which is made of sheet steel and coated with enamel. In the process of using water from the tank, the system automatically fills it.

Reverse osmosis systems are equipped with an additional faucet that is cut into the sink. Water from the tank passes through a post-filter filled with activated carbon and enters the faucet.

After passing the liquid through filters of this type, useful minerals are lost, therefore, in order to enrich the pure liquid with magnesium, sodium and calcium, a mineralizer is additionally installed. To restore the natural structure of water, a bioceramic cartridge filled with tourmaline is installed.

The complete set of the reverse osmosis system is as follows:

  • system of 4-6 flasks;
  • replaceable cartridges and membrane;
  • tank for purified liquid;
  • drinking tap;
  • assembly tool kits.

Install a reverse osmosis system under the sink. But another installation is also possible with additional hoses for supplying and discharging clean and dirty water. The performance of the system depends on the pressure, osmosis operates at 2-6 bar. If the indicators differ from those declared, then the pressure is increased by installing a pump or reduced.

The disadvantages of such a system include a low rate of purification and high fluid consumption (2/3 of the volume goes with impurities into the sewer).

Wash filters


Sink filters represent a single system consisting of 3-5 filter sections. The water coming from the tap goes through several stages of purification. Each section is a plastic, steel or glass-filled flask with a cartridge. This design is connected to a cold water supply under the sink with the output of purified water through a separate faucet.
Wash filters include:

  • flowing;
  • reverse osmosis.

The flow filter consists of the following modules:

  • mechanical cleaning from impurities of sand, rust, silt;
  • coal sorbent that removes chlorine, salts, organic compounds, heavy metals;
  • ion-exchange resins that soften water, remove iron, magnesium and potassium.

To protect the water after the flow filter from microorganisms, an ultraviolet lamp is installed.

Flow devices have a high throughput and efficiency in water consumption, unlike reverse osmosis models.

Reverse osmosis systems are additionally equipped with a membrane, a tank for collecting and storing purified water, as well as a mineralizer and a bioceramic cartridge.

They choose a filter for washing, having studied the characteristic indicators of water in the house. This will allow you to install cartridges with those fillers that are necessary to obtain drinking water. Then they proceed to the study of technical characteristics: the number of cleaning stages, productivity, the resource of replaceable elements, the dimensions of the installation, the availability of additional options.

The advantages of devices under the sink include:

  • ergonomic installation;
  • ease of operation;
  • interchangeability of filter systems;
  • long-term operation of replaceable elements (in flow devices, cartridges are replaced after 6 months, in reverse osmosis after a year);
  • saving the cost of clean water.

Disadvantages are the high price of equipment and stationary installation.

Water softeners


For softening, devices are used with the principle of replacing heavy calcium and magnesium ions with sodium or potassium ions. Many types of filters carry out the softening procedure, these include:

  • jugs;
  • main ion exchange;
  • reverse osmosis;
  • electromagnetic;
  • ultrasonic.

A common type of softeners are regenerative ion exchange filters. They consist of a filter section that is filled with ion exchange resin, a backwash mechanism and a tank for regeneration solution.

Over time, the ion exchange capacity of the resin decreases and must be restored. To do this, a regeneration solution is used – tableted table salt, it replaces the hardness ions accumulated in the resin with sodium ions.

This backwash process can be manual or automatic. To regenerate the filtering properties of the resin, the device stops working for 0.3-2 hours about 2-3 times a week. Systems that include a single ion exchange filter are considered variable.

And permanent devices have 2 ion-exchange sections, which are alternately restored without stopping the softening function.

Depending on the design, several types are distinguished:

  • balloon-type devices;
  • compact, where 2 elements (filter and tank) are connected into a single housing;
  • automatic systems.

The advantages of using the system include a high degree of removal of hardness salts and a long service life.

Compact models for softening are magnetic filters. They are presented in the form of a case with built-in magnets. Such a device is installed directly in the water supply pipe. The principle of operation is as follows: a magnetic field constantly acts on the water flow, as a result of which hardness salts cease to crystallize and settle on heating devices and on the walls of pipes of household appliances.

To protect household appliances from scale and soften the water entering the washing and dishwashers, boilers and radiators, softeners in the form of flasks are installed in front of the devices. These are transparent containers filled with polyphosphate crystals or filter material – ecozone, with a service life of about 6 months.

Water that has undergone a softening procedure for human consumption must be subjected to additional filtration from other compounds.

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