Arumloo’s Ultra-Low Flush Toilet

Trial Reservoir Success for Arumloo’s Ultra-Low Flush Toilet 

Ultra-low flush toilet achieves water savings of over 70% at trial site in Botswana.

Scarcity and limited resources leave 2.6 billion people without hygienic sanitation worldwide, heightening the risk of waterborne disease. Yet modern toilets, requiring 6-20 liters per flush, are inaccessible to those in deprived areas or lacking water systems.

South African company Arumloo Pty Ltd invented an ultra-low flush toilet that reliably clears waste using 2L of water per flush. Inspired by the vortex shape of the Arum Lily, the Arumloo’s design also reduces the need for multiple flushes. The company participated in the Climate Change Trial Reservoir to demonstrate the Arumloo’s performance and acceptance in a busy school in Botswana. Inadequate sanitation facilities at the school hindered learning, and toilet leaks and flushing significantly contributed to its water expenses.

NextGen Waterfree Solution replaced 120 toilets with Arumloos at a Gaborone school. NextGen offered to implement the water saving installations at zero capital cost to the school. In turn, the school agreed to pay a portion of the money saved for two years, up to 50%.

The trial results indicate the Arumloos produced a 71% water saving, far exceeding the target of 50% savings. Alongside the cost savings associated with water demand reduction, there is an annual carbon saving of 468kg CO₂e/year.

Benefits of Approach/Innovation

Significant water and cost savings: Before the trial the school’s water use reached 2303kL/month, with a water bill exceeding P200,000 (USD $14,870) per month. Following the ultra-low flush Arumloo’s installation the toilets saved more than 270kL/month.

Leakage prevention: The school’s previous sanitaryware was old and leaky. Sub-metering within the new Arumloo toilets confirmed no recorded leakage.

Reduced GHG emissions: The Arumloos save the school 1171kL water annually, equivalent to a 585.5kWh energy saving. As 93% of Botswana’s power is derived from non-renewable sources, this school alone saves 468kg CO₂e annually.

Risk-free trial: Trial Reservoir loan funding provided an opportunity for Arumloo and NextGen Waterfree Solution to test the technology risk-free.

Specialist Services Involved:

Trial Design support: We evaluate technology trial plans based on users’ innovation frames.  The Trial Reservoir specifically addresses key questions that the trial must answer.

Trial validation: We receive and assess the trial end report from the technology vendor. The Trial Reservoir specifically addresses key questions that the trial must answer.

Due Diligence: Isle has a robust process for helping stakeholders adopt innovative technologies and ensuring they are fit for purpose.

Loan funding: Isle facilitates negotiation with technology developers and end users to agree upon the trials’ critical success factors and key performance indicators (KPIs). Loans are then released to the technology developers.

Zero Risk Trial: Should a trial not meet its KPIs, there is no obligation for the tech company to pay back the loan. Similarly, there is no obligation for the end user to make a purchase order; the Trial Reservoir assumes the risk.

Investor Introductions: Isle uses its extensive worldwide network to provide introductions to potential investors.


Water savings: The toilets produced a 71% water saving, far exceeding the trial’s target of 50% savings.

Nationwide expansion: The trial’s success in reducing water demand and preventing leakage has attracted nationwide attention. Visits from schools and the Ministry of Education led to NextGen’s appointment to install Arumloos in other schools and public buildings.

Key Contacts:

For inquiries and further information, please contact Dr. Jo Burgess, Head of Trial Reservoir at Isle.


Photo credit: Arumloo Pty Ltd

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Arumloos greatly reduced water leakage and usage, cutting school’s water bills and GHG emissions
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