Domestic water-saving flush with potential

Could a simple blue pellet unlock domestic water conservation? With climate change and regulatory targets tightening, this small innovation could be a big part of the UK's water-saving future, says Mark Gilligan , director, Wizso.

Imagine if there was a pill that the water industry could take that would address multiple problems in one dose. Maybe it would reduce household demand for clean water by 20%, lower customer bills and cut carbon emissions.

As clean water use comes down, it would also slash discharge to sewers, ensuring more wastewater is processed at treatment plants, delivering a positive impact on river health, and helping water companies get much closer to their regulatory targets.

This scenario is not a fantasy. There is a small blue pellet that – along with a positive change in customer behaviour – can facilitate water demand reduction at scale.   

Wizso is a dissolvable non-toxic pellet dropped into the toilet after urination. It changes the colour of the water to a recognisably clean blue and releases a fragrance to mask any odour, enabling users to flush less often, saving significant volumes of fresh water.   

Given that the average person flushes around seven times a day, and an average flush using approximately seven litres, the potential savings are considerable.   

A trial undertaken by Affinity Water at a housing development in Bidwell, Bedfordshire, demonstrated that participants who engaged in a doorstep conversation about water-saving, committed to a water-saving pledge, and used Wizso pellets, managed to save an average of 51.1 litres of water per day in their household. This translates to around one-third of total daily individual usage. 

The importance of reducing water consumption cannot be understated. The UK is exiting its hottest summer since records began, according to the Met Office, with some reservoirs still at very low levels. Extremes of climatic variability can be expected to continue in the coming decades due to global warming, which is only one of the stressors on water supplies.   

The final report from the Independent Water Commission released in July 2025 recommends reducing household consumption through compulsory smart metering to better manage water demand (and address leakage). The report also recommends public education and awareness campaigns around the importance of water conservation; this could be strengthened by asking people to take personal actions to reduce usage. 

According to Ofwat, the average reduction in consumption when a water meter is installed is 10%, and the Environment Agency has made it clear that water metering alone will not sufficiently reduce domestic water consumption. The Government's legally binding target under the Environment Act 2021 is to reduce public water supply per person to approximately 122 litres per person per day by 2038, with a longer-term goal of reaching 110 litres/day per person by 2050 – a reduction of over 20 percent.   

Even with smart metering, that leaves a big gap for the talented teams delivering customer behaviour initiatives within water companies to bridge. Affinity Water has already demonstrated how combining information, a nudge and the distribution of Wizso drives greater efficiency and gives customers better control over their total consumption.  

Importantly, a wider roll-out of smart metering will make it easier to measure the effectiveness of customer behaviour trials much more closely. One of the observations around a 2023 report from CCWater on customer behaviour campaigns was that "there has been a lack of thorough and consistent evaluation of their impact in the short and longer-term.”  

Clearly smart metering is not a solution on its own, but once combined with properly evaluated customer behaviour campaigns, backed by a proven technique that can save up to 30% of water used in toilet flushing, a giant wave of water-saving can be generated.  

Our toilet habits are a highly personal and private area of daily life, but the Affinity trials show that, given the right information, customers understand the issue and are willing to try new approaches and save on flushing. Some households have long been loyal to the maxim ‘If it’s yellow let it mellow’ - with an eye to the cost of living, or environmental concerns, or both – and Wizso can enhance their experience. For everyone else, Wizso makes it easier to catch up.  

With water resources across the UK under pressure and already impacting economic growth and development – including planning for housing, Wizso could be the dose of reality needed to move water conservation to the next level. I look forward to hearing from more water companies and environmentally focussed organisations interested in exploring the potential of Wizso via verifiable trials, both within their businesses and the homes of their employees, and with their own customers.  

Taxonomy

• Water