• Challenge Works has launched the Flush Forward Challenge to tackle sewage and nutrient pollution and water scarcity.
• Up to three UK organisations will receive £40,000 each and expert support to investigate non-sewered sanitation challenges in their region and develop plans incorporating Reinvented Toilet technologies and other novel solutions.
• The challenge is seeking organisations that want to better understand the effects of non-sewered sanitation on local communities and environments.
• Reinvented Toilet technologies can safely process waste without connections to mains water, sewers or mains power, with the potential to provide an alternative to septic tanks and other conventional sanitation infrastructure.

Challenge Works has today launched the Flush Forward Challenge, which will fund and support UK organisations to explore how Reinvented Toilet technologies could help address sewage and nutrient pollution, water scarcity and other challenges associated with non-sewered sanitation. The Flush Forward Challenge is funded by the Gates Foundation.

Around one million UK homes are not connected to mains sewers and instead rely on septic tanks, cesspits or small sewage treatment plants.

Septic tanks provide only primary treatment, with the surrounding ground performing much of the remaining treatment. Their outputs are not free from pathogens, while harmful nutrients including nitrogen and phosphorus can enter the natural environment. With septic tanks typically lasting between 20 and 40 years, an estimated 25,000 to 50,000 systems could require replacement each year.

At the same time, pressure on the UK's wider wastewater and water infrastructure is growing. In 2025, England and Wales recorded 386,466 wastewater discharge events into waterways, lasting a combined 2.65 million hours. They pose a danger to human, animal and plant health. The phosphorus and nitrogen found in sewage promote the growth of algal blooms which suck the oxygen out of waterways, a process called eutrophication, leading to the deaths of many aquatic species and leaving waterways barren. 

Beyond that, the country flushes more than 2.4 billion litres of drinking water down the toilet every day at a time when it is being asked to use water more efficiently.

The Flush Forward Challenge will explore whether Reinvented Toilet technologies could provide part of the solution. Reinvented Toilet technologies do not need a water, sewer or mains power connection and can safely and cleanly process waste in their own system, with the potential to provide an alternative to septic tanks and other conventional sanitation infrastructure.

Up to three organisations will each receive £40,000 to fund six months of staff support, alongside systems-thinking training, mentoring and regional analysis of non-sewered sanitation. Participants will investigate the sanitation challenges affecting their region and areas of responsibility, bring together relevant stakeholders and develop a compelling vision for how new technologies and other solutions could mitigate them.

Catherine Duncan, Senior Programme Manager, Challenge Works said:

"Septic tanks and municipal sewers are 19^th century inventions that are not meeting the expectations of people or the needs of the environment.

"Organisations working in areas affected by non-sewered sanitation understand the pressures facing their environments and communities better than anyone. Through the Flush Forward Challenge, we want to give these problem owners the funding, evidence and practical support they need to explore whether a new generation of non-sewered sanitation technologies could offer a better way forward.

"Reinvented Toilet technologies have the potential to treat waste safely without relying on water, sewer or mains power connections. By working with organisations that manage issues first-hand, we can build a clearer picture of where the technologies could make a meaningful difference in the UK."

The challenge is seeking entries from organisations that contend directly with the social and environmental effects of non-sewered sanitation. These could include councils, environmental groups, river trusts, national parks and small water companies, known as NAVs (New Appointments and Variations).

It is particularly interested in working with organisations in regions that have significant nitrogen or phosphorus issues and a high prevalence of septic tanks or other forms of alternative sanitation.

Challenge participants will convene stakeholders and analyse the non-sewered sanitation issues affecting their region. They will then identify potential interventions and technologies, including Reinvented Toilet and other ISO 30500-accredited technologies, that could mitigate those issues. The goal is to develop a clear, evidence-led vision of the benefits that these technologies could offer within the UK.

Reinvented Toilet systems can range from compact treatment technology incorporated into a single bathroom toilet to larger waste-processing systems that could replace a septic tank. They are designed to remove harmful pathogens and environmental contaminants, clean water and recover useful resources such as nitrogen, phosphorus or biochar.

For properties that are not connected to sewers, the technology could offer a more sustainable alternative to a septic tank by treating waste fully and preventing pollutants such as nitrogen and phosphorus from entering the environment. It could also support housebuilding in places where development is being delayed by limited sewer capacity or nutrient neutrality requirements.

The UK and other high-income countries can provide a strategic launchpad for Reinvented Toilet technologies because of their mature markets and regulatory systems. Demonstrating the technologies successfully in these settings could help build confidence, establish a market and reduce production costs, supporting their wider adoption internationally, particularly in low- and middle-income countries.

Unsafe water, sanitation and hygiene are responsible for around 1,000 deaths of children under five every day worldwide, according to UNICEF. The Reinvented Toilet leapfrogs the need to establish large-scale sewer networks and wastewater treatment works and is designed to work off-grid with little water. Around the world, these technologies hold life-changing potential for the 3.4 billion people who lack access to safe sanitation.

Entries for the Flush Forward Challenge open on 5 October 2026 and close on Wednesday 16 December 2026 at 12 noon (GMT). To enter or find out more, visit flushforward.challenges.org.