Softened water

Hard water contains calcium and magnesium that can cause scale formation in pipes, heat exchangers, boilers and membranes. In industrial processes, this leads to reduced efficiency, higher energy consumption, increased maintenance and unplanned downtime. Water softening removes hardness at an early stage, protecting equipment and ensuring stable, predictable operation across the entire water treatment system.

Where is water softening used?

Water softening is used both as pretreatment to advanced technologies and as a stand‑alone solution for drinking water and process water applications. In industries such as food & beverage and pharmaceuticals, softened water with drinking water quality is used directly in production to ensure consistent quality and reliable operation.

Removed elements
  • Calcium (Ca++)
  • Magnesium (Mg++)

Pretreatment to reverse osmosis

Removing calcium and magnesium before RO protects membranes from scaling, ensuring stable performance, lower energy consumption and longer membrane lifetime. Softening helps secure reliable operation and predictable water quality in RO-based systems.

Boiler feed water and heating systems

Softened water is widely used as boiler feed water to prevent scale formation in boilers, heat exchangers and district heating systems. This improves heat transfer, reduces maintenance requirements and supports energy-efficient operation.

Drinking water treatment at waterworks

Groundwater often contains high levels of hardness. Softening helps prevent scaling in distribution networks, household plumbing and installations, improving long-term infrastructure reliability and end-user comfort.

Drinking water quality for industrial use

In industries such as food & beverage, pharmaceuticals and utilities, softened water with drinking water quality is used directly in production processes, ensuring consistent quality while minimizing scale-related challenges.

See products used for water softening

Explore related technical references

Water treatment for juice production

Water treatment for juice production

Rynkeby Foods A/S is the largest manufacturer of juice and cordials in the Nordic region.

In connection with an expansion of the production, there was also a need for a larger amount of process water. Grundfos has supplied the water treatment solution for producing the water qualities of softened water and demineralised water for the following purposes:

  • cleaning
  • make-up water for steam boiler
  • rinse water for juice bottles
  • lubricant for food grade pumps

Industry: Food industry

Application: Boiler water | Process water | Rinse water

 

Technical data:

  • Flow demineralised water: 8 m³/h
  • Conductivity: <20 µS/cm
  • Flow booster pump: 80 m³/h

Units in plant:

  • Softening unit type SMH 1202-F
  • Reverse osmosis unit type RO C3-6 with SE30 control panel
  • Buffer tank in PP 39 m³
  • Booster pump

Water treatment for hygienic washing of textiles

Water treatment for hygienic washing of textiles

Grundfos has designed, produced, supplied, and installed a complete water treatment plant for producing water for washing of textiles and boiler feed water.

The company behind the laundry is SALESIANER MIETTEX, a well-known company with more than 100 years of experience within textile management. The production facility has great focus on sustainability and hygenic washing. 

Industry: Laundries | Textile industry

Application: Boiler water | Process water

 

Technical data

  • Flow washing water: 70 m3/h
  • Flow boiler feed water: 3 m3/h
  • Conductivity: < 20 µS/cm

Units in plant:

  • Softening unit type STFA 25 with SE20 control panel
  • Brine maker type SE3500 with SE10 control panel
  • Storage tank for softened water
  • Booster pumps 3 x CRNE 20-4
  • Storage tank for hot water
  • Booster pumps 3 x CRNE 45-2
  • Softening unit type SMH362 with SE20 control panel
  • Reverse osmosis unit type RO B2-8 with SE30 control panel
  • Storage tank for demineralised water 3 m3

Long life softener for heating plant

Long life softener for heating plant

Softening units are a long-time investment and Grundfos uses the best materials available. That is why the existing water softener at a Danish heating plant was still running after 20 years. It was only due to a major renovation that it was decided to replace the existing plant with a newer model. According to the operator, it easily could have run for a few more years.

Grundfos has delivered and installed the new volume-controlled water softener and new pressure tank. Softening prevents calcium deposits in piping, steam boilers, and heat exchangers.

The advantage of a volume-controlled unit is that it fully utilises its capacity. It can be a good and economical solution for an irregular water consumption since the number of regenerations is adapted to the pattern of consumption.

The new water softener produces 2.500 m3 softened water per year, which is heated and through a pressure tank sent to the consumers.

Industry: Heat and power plants
Application: Boiler water | District heating water

 

Technical data

  • Flow: 2500 m³/year

Units in plant:

  • Softening unit SMH 362 with SE20 control panel
  • Pressure tank
  • Storage tanks

Water softening by ion exchange in municipal drinking water treatment

Water softening (Ion Exchange) in municipal drinking water treatment

As the first water utility in Denmark, TÅRNBYFORSYNING is providing softened drinking water using ion exchange technology. The softening unit is supplied by Grundfos.

The presence of calcium (Ca) and/or magnesium (Mg) in water results in water being considered “hard.” Calcium and magnesium ions in water react with heat and metallic plumbing and will produce lime scale buildup. Further more, hard water reacts with chemical agents such as detergents to decrease the effectiveness of nearly any cleaning task. Hard water can be softened using an ion exchange softening process.

Industry: Waterworks

Application: Drinking water

Technical data

  • Flow: 3 x 55 m³/h (max.)

Units in plant

  • Softening unit type STFA 17 triplex
  • Salt brine tank with capacity of 30 ton
  • UV disinfection unit type Wedeco Spektron 180