Centre of Evidence Based Dermatology

Softened Water Eczema Trial


The Softened Water Eczema Trial (SWET) involved 336 children with eczema. It was designed to evaluate whether installing an ion-exchange water softener into the homes of children with eczema could help to reduce the severity of the condition.

The study took place in areas of the UK where the water is naturally hard (London, Nottingham, Cambridge, Isle of Wight, Portsmouth, Leicester and Lincoln/Boston).

The clinical trial was led by Professor Hywel Williams and Dr Kim Thomas of the Centre of Evidence Based Dermatology at the University of Nottingham.

Softened Water Eczema Trial logo 


Key Finding

It had been hoped that water softeners would provide simple but effective relief for the many children who suffer from this itchy and uncomfortable condition. However, the trial showed no objective difference in outcomes between the children whose homes were fitted with a water softener and those without.


Professor Hywel Williams, chief investigator of the trial, comments on the study results in the video below.


SWET has been used as a case study in a major report assessing the impact of the NIHR Health Technology Assessment (HTA) Programme. The report, produced by RAND Europe, looked at the impact of HTA funded research from 2003 to 2013 on patient health, clinical practice, health policy, the economy and academia.



Trial Documents


tel: +44 (0) 115 846 8632
email: cebd@nottingham.ac.uk

The researchers would like to thank all of the families and children who kindly took part in the SWET trial for their support and enthusiasm throughout the trial.

This trial was funded by the National Institute for Health Research, Health Technology Assessment Programme. Generic water softening units (including salt supplies) and technical support were provided by a consortium of partners from the water industry whose involvement was co-ordinated through the Trade Associations: UK Water Treatment Association and British Water.


British Water  


Centre of Evidence Based Dermatology

The University of Nottingham
Applied Health Research Building
University Park, Nottingham

telephone: +44 (0) 115 84 68631
email: cebd@nottingham.ac.uk