Modernizing water testing for global impact
Increasing access to water quality tests in low-income communities is a crucial strategy toward achieving global water equality. Recent studies in the Water Sanitation and Hygiene (WASH) sector underscore the importance of addressing practical concerns in water testing, such as robustness and results communication.
In response, we present the WaterScope testing kit; an open-source, validated platform for drinking water quality assessment. It modernizes the testing process with the inclusion of a unique cartridge/slider mechanism, machine-learning-enhanced classification, and full digitalization of results. WaterScope’s equivalency to conventional methods for quantifying E. coli is established through extensive validation experiments in both laboratory and field environments.
This versatile platform provides potential to expand its applications to test other bacteria, perform colorimetric assays, and analyze clinical samples such as blood/urine samples. We anticipate that the system’s ease-of-use, portability, affordability, robustness, and digital nature will accelerate progress toward global water equality.
Addressing practical challenges in water testing
Microbiological water monitoring has been identified as a key factor in improving humanitarian WASH interventions. By improving access to affordable, reliable, locally-available and easy-to-use water testing technologies, communities can be empowered to respond proactively to outbreaks and live with increased confidence in their drinking water supply.
Existing water testing methods, however, often fail to meet the needs of resource-constrained settings. Factors such as high logistical costs, complex workflows, and poor integration of data reporting systems have limited their widespread adoption. Additionally, the manual nature of traditional enumeration techniques can introduce human error, further compromising the accuracy of water quality assessments.
Through an iterative human-centered design (HCD) approach, the WaterScope team engaged directly with WASH professionals, field technicians, and community members to understand their pain points and design solutions tailored to their unique needs. This process revealed several key insights:
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Simplifying the testing workflow: The multiple steps required in conventional membrane filtration methods, such as sample preparation, media addition, and incubation, can be error-prone and labor-intensive. Integrating these steps into a self-contained cartridge system significantly reduces the complexity and potential for user mistakes.
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Automating result interpretation: Existing systems depend on the user’s ability to manually identify and count bacterial colonies, a task that can be prone to human error. WaterScope’s embedded microscope and machine learning algorithms automate this process, providing reliable, digitized results.
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Improving data management: Traditional water testing methods often require external data management systems, adding another layer of complexity. WaterScope’s built-in connectivity enables seamless digital reporting and real-time data sharing, improving transparency and enabling faster response times.
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Ensuring robustness and portability: Water testing in remote or challenging environments requires durable, portable, and energy-efficient solutions. WaterScope’s compact, rugged design and low-power operation make it well-suited for field deployments.
By addressing these practical considerations, the WaterScope system aims to overcome the barriers that have historically hindered the widespread adoption of water quality monitoring in resource-constrained settings.
Validating the WaterScope approach
To comprehensively assess the performance of the WaterScope system, the team conducted a series of validation studies in both controlled laboratory settings and real-world field environments.
Laboratory validation
The first validation study compared the WaterScope method to three established reference techniques: Chromogenic Coliform Agar (CCA), Colilert-18, and Membrane Lauryl Sulphate Broth (MLSB). A 5-fold dilution series of E. coli was prepared, and 14 replicates were tested for each method.
The results showed a strong linear relationship between WaterScope and the reference methods, with coefficients of determination (R^2) ranging from 0.75 to 0.92. Statistical analysis further confirmed that the WaterScope approach was not significantly different from the ISO-recommended CCA and Colilert-18 methods at a 95% confidence level.
Field validation
To assess the WaterScope system’s performance in real-world conditions, the team conducted a year-long study monitoring the water quality of the River Cam in Cambridge, UK. Biweekly samples were analyzed using WaterScope, CCA, and Colilert-18 methods, with 2-5 replicates per sample.
The field data revealed excellent agreement between the WaterScope and reference methods, with R^2 values of 0.95 and 0.94, respectively. Seasonally fluctuating E. coli levels were consistently captured across all testing approaches, further validating the system’s reliability in complex environmental matrices.
Humanitarian field trials
To evaluate the WaterScope system’s suitability for humanitarian water quality monitoring, the team conducted three field trials in East Africa: Juba, South Sudan (May 2022); Kawangware, Kenya (September 2022); and Addis Ababa, Ethiopia (June 2023). These trials assessed the system’s robustness, user-friendliness, and adaptability to diverse field conditions.
Over the course of these trials, 301 water samples were analyzed using WaterScope and the Compact Dry reference method. The results showed a strong correlation between the two approaches, with Spearman rank coefficients ranging from 0.75 to 0.91 across the three trials.
Importantly, the team identified and addressed several challenges encountered during the initial field deployments, such as residual contamination in the reusable components. By implementing targeted improvements, such as enhanced sterilization protocols, the team was able to significantly improve the system’s performance, achieving false positive rates as low as 5% in the final Addis Ababa trial.
Expanding the scope of water quality monitoring
The versatility of the WaterScope platform extends beyond just E. coli enumeration. By leveraging the integrated microscope and customizable cartridge/slider design, the system can be adapted to perform a range of additional water quality tests and clinical analyses.
Colorimetric assays
The WaterScope microscope can be used to analyze colorimetric test strips, enabling the quantification of parameters such as chlorine, pH, and heavy metals. This functionality allows the system to serve as a compact, all-in-one water quality testing solution, addressing a broader range of analytical needs.
Clinical applications
With minor modifications to the cartridge and media components, the WaterScope system can be repurposed for clinical applications. For example, the team has demonstrated the system’s capability to detect and analyze urinary tract infections, as well as assess the antibiotic susceptibility of bacterial pathogens.
Open-source development
By openly publishing the WaterScope design files and software, the team aims to foster a collaborative community of innovators who can further enhance the system’s capabilities. This open-source approach facilitates local customization, simplifies maintenance and repair, and reduces reliance on proprietary consumables.
Catalyzing progress toward global water equality
The WaterScope testing platform represents a significant step forward in improving access to reliable water quality monitoring, particularly in resource-constrained settings. Its ease-of-use, portability, affordability, and digital integration make it well-suited for deployment in humanitarian WASH programs and community-based water quality monitoring initiatives.
Looking ahead, the team is exploring opportunities to integrate the WaterScope system with established disease surveillance and water quality reporting platforms, such as SORMAS and mWater. By seamlessly connecting water quality data with broader public health and environmental monitoring efforts, the WaterScope can contribute to more informed decision-making and accelerated progress toward the United Nations’ Sustainable Development Goal 6: ensure access to water and sanitation for all.
As the open-source WaterScope community continues to grow, the team is excited to see how this versatile platform will be adapted and applied to address diverse water quality challenges around the world. By empowering local communities with the tools and knowledge to monitor their own water resources, the WaterScope aims to be a catalyst for achieving global water equality.
To learn more about the WaterScope system and explore opportunities for collaboration, please visit https://jointactionforwater.org/.
