Can I Put Softened Water In My Central Heating System?

Here at Friendly Water a commonly asked question from our customers is can I put softened water in my central heating system?

The official answer from UKWTA (United Kingdom Water Treatment Association) is yes!

“British Standard BS 7593:2006 Code of practice for treatment of water in domestic hot water central heating systems has recently been updated and now allows systems, including those with boilers with aluminium heat-exchangers, to be filled with softened water provided that a corrosion inhibitor specifically formulated for the purpose is added and properly maintained”.


The UKWTA have also issued the following statement regarding artificially softened water and boilers and water heaters with Aluminium heat-exchangers.

“Naturally soft waters of low alkalinity have a tendency to increase the corrosion of metals typically used in the construction of domestic boilers. This has led to the misconception that all artificially softened water is corrosive and should not be used in domestic boilers and central heating systems under any circumstances.
In fact, softening has been shown to be beneficial to most system metals when small amounts of dissolved heavy metal ions that are present in the water are removed by the softening process (these have a tendency to increase corrosion).”


Worcester Bosch have now publicly announced that their position has now been revised and in the words of Martyn Bridges, Director of Marketing and Technical Support at Worcester Bosch
“It is considered acceptable to fit a water softener to a house in a hard water area…..On the condition that at the filling point of the system within the property the water remains untreated”


Further information: http://www.ukwta.org/pdfs/UKWTA-SoftenedWaterAluminium.pdf