Safe water with certainty.

PotaVida lowers the cost of access to safe water in disasters and urban slums, and enables program evaluation by automating the collection and reporting of usage data.


PotaVida's mission is to lower the cost of getting safe drinking water to people who need it.

Lowering the Cost of Access to Safe Water: Despite $30B spent annually on water and sanitation development projects, 700 million people do not have access to clean water. People's needs are not met by local infrastructure and existing household level disinfection methods are too expensive. Disaster relief also reveals unmet need for safe water: $9B has been spent on disaster relief in Haiti, yet over 700,000 people have been infected with Cholera, a waterborne disease, and as a result over 9,000 people have died. The NGOs and governments that respond to these disasters need a lower cost method of disinfecting water reliably that does not rely upon consistent supply chains.

We provide a lower cost of access to safe water over any competing point-of-use technology. Requiring only a single distribution, our purifier not only reduces costs, but also avoids dependence on supply chains for ongoing access to safe water.

Enabling Efficient Use of Resources: NGOs and governments need better data to optimize their choice between existing options. Today they rely upon in-person surveys to collect information on the use of water purification systems. Surveying a household takes 20 to 30 minutes of staff time per household, and the resulting self-reported data suffers from yeah-saying bias. These institutions need a faster way to collect more accurate data so they can reach more people more efficiently.

Our wireless data transfer between water purifiers and a smartphone-based capture device reduces data collection time and improves accuracy, enabling program evaluation at a lower cost. We make it possible for NGOs and governments to reach more people with existing funds.

PotaVida's Product... Different, Better, Cheaper

We tell you when your water is safe to drink.

Until now, there has not been a reliable way to determine when solar disinfection has actually been achieved. PotaVida has developed a simple UV and temperature monitor that visually indicates to users when water disinfection is underway, and when water is safe to drink. Users can press a button to query disinfection status at any point. The electronic monitor stores usage data, which can then be wirelessly transmitted to a handheld smartphone-based device for upload to an online database along with GPS position.

PotaVida's current purifier design is a 3L water bag with an integrated solar disinfection monitor and data logger. The solar disinfection monitor tracks cumulative exposure to sunlight and uses LEDs to indicate when sufficient exposure has been reached to inactivate pathogens in the water. Users can simply fill the bag with water, place it in the sun, push a button, and wait for the LED indicator to indicate that the water is safe.
PotaVida make it as easy as one, two, three:

  1. Fill the PotaVida purifier with clear water, and place it in the sun.
  2. Press start button.
  3. Look at the lights. Red light = in progress, and green light = safe to drink.

Technical Summary

The World Health Organization recommends solar disinfection.

The World Health Organization recommends solar disinfection, a process that uses the UV in sunlight to inactivate pathogens in water. Both bacteria and viruses are inactivated by solar disinfection. The process takes a few hours, depending on weather, water clarity, and the UV transparency of the container. In addition, temperatures above 45°C increase the speed at which pathogens are destroyed. When combined with these increased temperatures, amoebeas, cysts, and spores are also destroyed by solar disinfection.

Depending on conditions, users can complete as many as 3 disinfection cycles daily, using the PotaVita bag. We plan to increase the current 3L bag capacity to 5-6L, enabling up to 18L of water disinfection per day. The bag-based design is foldable and stackable for shipping efficiency. Because the purifiers use no consumables and will operate for several years, the cost per unit volume of safe water over the lifetime of the device is lower than any competing point-of-use water disinfection technology.

Meet the Team

PotaVida brings together experts with a passion for sustainable and scalable global health solutions.


CEO Charlie Matlack, PhD

Charlie is the CEO of PotaVida and handles engineering tasks. Charlie earned his Ph.D. in Electrical Engineering from the University of Washington, and attended Harvey Mudd College as an undergraduate. Charlie has a background in multiple engineering disciplines with an emphasis on systems design. He is an expert in electrical and mechanical design and prototyping, in particular with embedded digital systems. His dissertation work was on novel interfaces for enabling individuals to control prosthetics and computers using individual neurons in the brain. He is an entrepreneur who understands how to leverage for-profit business and technology development models to provide market-based solutions to the developing world.


Jackie Linnes, PhD

Jackie is a VP and handles biological compliance tasks. Jackie holds a Ph.D. in Bioengineering and a certificate in Global Health from the University of Washington. She is an expert in bacterial pathogens and implementing engineering solutions that improve global health. Jackie has extensive global health implementation experience, including the development of the PotaVida purifier as well as leading an assessment of user response and usage of improved cooking stoves for Engineers Without Borders in rural Bolivia. Jackie has taught at MIT, Harvard and currently teaches at Boston University.


Tyler Davis, PhC

Tyler is a VP and handles business development and field work trials. Tyler is a Ph.D. candidate at the Evans School of Public Policy. His background is in benefit cost analysis. Tyler's dissertation work is third party certification of environmental goods. His research experience includes economic modeling in Indonesia of subsistence economies, development of principles and standards for benefit cost analysis for social programs, and benefit cost analysis of access to information and communication technology. Tyler has extensive experience conducting fieldwork in developing countries, including Indonesia and Mexico.


Q: Don't dangerous chemicals leach from plastics, especially when left in the sun?

A: Thin-walled polyethylene terephthalate, labeled PET or PETE in the US, can be safely used for SODIS. These are marked with the "1" recycling symbol when used for plastic bottles. Glass bottles should not be used because most glass has UV-blocking additives.

Valid concerns about hazardous chemicals leaching from PET bottles left in the sun have been addressed by scientific studies. Leached organic compounds are 10 times lower than the safe amount for drinking water as defined by the WHO. No other chemicals are leached.

Q: How large a problem is contaminated drinking water?

A: "The sheer scale of dirty water means more people now die from contaminated and polluted water than from all forms of violence including wars," the United Nations Environment Programme (UNEP) said. This includes 2.2 million people whose deaths are attributed to diarrhea, mostly from dirty water, and 1.8 million children aged under five who succumb to water-borne diseases. This equates to one infant every 20 seconds. Christian Science Monitor (3/22/2010)

Preventable deaths from diarrheal diseases account for 1.4 million or 18% of all deaths in children under five per year. WHO (2010)

Q: How effective is SODIS at solving this problem?

A: SODIS kills 99.999% of target pathogens. See table below.

Q: How much does SODIS cost compared to other water treatments?

A: Solar disinfection cost less than chlorination, filtration or flocculation disinfection.

Annual cost comparison of different interventions to improve water quality. Reproduced from Casen et. al. 2007

Q: How does solar disinfection (SODIS) work?

A: Three effects of solar radiation kill or deactivate dysentery-causing organisms:

  1. Ultraviolet light interferes directly with the metabolism and destroys cell structures of bacteria.
  2. Ultraviolet light reacts with oxygen dissolved in the water and produces highly reactive forms of oxygen (oxygen free radicals and hydrogen peroxides) that are believed to also damage pathogens.
  3. Cumulative solar energy (including the infrared radiation component) heats the water. If the water temperatures rises above 50°C, the disinfection process is three times faster.

Scanning electron micrograph of oocysts of C. parvum. (a) C. parvum at 40°C at time = 0 h. (b) C. parvum at 40°C at time = 10 h. (c) C. parvum at 40°C + 870 W m^-2 at time = 10 h. (d) Wide field view of C. parvum at 40°C + 870 W m^-2 at time = 10 h. Magnification is x30,000. In each case the scale bar represents 1nm.

Reproduced from McGuigan, Kevin G., Ronan M. Conroy, Hans-Joachim Mosler, Martella du Preez, Eunice Ubomba-Jaswa, and Pilar Fernandez-Ibanez. 2012. "Solar Water Disinfection (SODIS): A Review from Bench-Top to Roof-Top." Journal of Hazardous Materials 235-236 (October): 29-46.

Q: How does the PotaVida indicator work?

A: Our indicator measures the time and intensity of UV exposure from the sun. It differentiates between darkness, partial sun, and full sun, and indicates when the process is working and when it is done. This way, people can learn and have confidence in SODIS.

Contact Information

How You Can Help

PotaVida is raising funds to conduct a 1000 unit field trial. Please Contact Us if you wish to support us!

Potavida Blog and News

Bimbe, Zambia

May 01, 2013 by PotaVida

Field visit to Bimbe, Zambia - a field visit success!

In April, Jackie Linnes and her husband Michael traveled with our World Vision Zambia partners to Bimbe, Zambia, 40km northwest of capital city Lusaka. The trip was an important milestone in our effort to improve our product before we produce it on a mass scale. It had two goals:

  • Learn more about the community: what were their current drinking water activities and thoughts on solar disinfection?
  • Get feedback from real-world users of our PotaVida Solar Water Purifiers: a critical step in helping us improve its utility and potential for impact.

We're thrilled to report we met both goals. (If you've been in the development world a while, you know field visits can be full of surprises, not always the good kind; meeting your trip objectives is never a sure thing!). Here's a rundown.

In terms of sourcing, we learned the people of Bimbe get drinking water from two main sources: an unprotected hand-dug well and a stream (which runs past numerous agricultural fields). In the past safe water came from a borehole and a deep protected well. But the well collapsed, and the borehole is now obstructed — it takes nearly two hours to hand pump water to the surface, say villagers. That means both sources presently yield water that's not safe to drink.

When it came to disinfecting the water for drinking, because of World Vision’s previous WASH campaigns in Bimbe, the community is acutely aware of the dangers of unsafe water. They presently disinfect their water either with chlorine or by boiling it. The government only runs free chlorine promotion campaigns in the rainy season, so chlorine is unavailable for the dry season - six months out of the year. During that time women have to gather firewood to boil drinking water. They boil water at night, so it can cool overnight for drinking the next day.

Given these circumstances, community members were excited about using the PotaVida Solar Water Purifiers (below left). They had had the prototype purifiers for several days in advance of our visit, and were ready to discuss them with us when we arrived.

The photo at right shows the Solar Water Purifier prototypes in the community. The top bag is filled with tap water, while the bottom one contains water from the local borehole, colored by iron oxide particles.

We learned most families chose to put the purifiers on their dish drying rack: it was a readily available sunny location, where animals wouldn't disturb the purifiers and the disinfection process (below right). We answered many questions, and we got incredibly useful feedback on the purifiers. Some examples:

  • More water is better -use 10L instead of 2L bags
  • Make the on/off switch easier to access
  • Change the zipper top
  • Brighter and different colored indicator lights would be easier to see and understand

We left our current models in the village for the community to continue testing. We're excited with the info we came away with: the feedback from real users gives us confidence we're on the right track, and gives us ground-truthed suggestions for ways to make our product even more useful!

purifier on dishrack

October Update: Field & Microbiology Testing, Design Changes

October 01, 2013 by PotaVida

Hello everyone! It has been another intense month for the PotaVida team. We have monitors in six countries for expert review, an independent university laboratory testing our monitors, and a new, more user friendly water bag that will make monitoring your solar disinfection simpler and more intuitive.

PotaVida Prototypes go to Africa, Europe and Latin America!

We currently have expert advisors in Spain, Ghana, Zambia, and Senegal reviewing PotaVida prototypes. Special thanks to Fundacion SODIS director Matthias Saladin, World Vision Core Program Manager for Western Africa Sam Diarra, World Vision Water and Sanitation Director for Southern Africa Emmanuel Opong, Royal College of Surgeons in Ireland SODIS researcher Kevin McGuigan, and WaterAid Nicaragua Country Director Joshua Briemburg.

These experts are providing excellent feedback on the usability, desirability, and intuitiveness of the monitors. We are thrilled to have their insight into the value-add that the monitors provide to the SODIS process. In Senegal specifically, 100% of the SODIS users interviewed by Dr. Kevin McGuigan's research group liked the monitor and supported the technology because they can easily know when their water is treated.

Use Cases: A Great Design Exercise

Charlie and Jackie collaborated with Essential Design engineer Scott Stropkay on thinking about our monitor design in the context of specific usage cases. This led to the selection of our water bag model with an integrated PotaVida monitor. We believe that an all-in-one package which doesn't require the user to provide a container or fasten a monitor to it will simplify the disinfection process and user interaction. The net result is a better design that is more intuitive and will safely store disinfected water.

University of Arizona Microbiological Testing is Underway

PotaVida sent four of our SODIS monitor prototypes to Dr. Chuck Gerba's lab at the University in Arizona at the end of September. This week, the lab is performing their first tests with our monitors in order to correlate our light measurements with E. coli die-off rates. We're eager to hear the results of these initial experiments. These, and the follow up tests, will be used to calibrate and evaluate our bag and bottle prototypes under diverse temperature, cloud cover, and turbidity conditions.

Thanks for reading!

From Washington DC to Kenya to Seattle…

July 16, 2012 by PotaVida

The PotaVida team attended the Aid and International Development Forum in Washington, D.C. June 6-8th, where we met with partner World Vision and Melissa Minke from Access Afya. The trip was extremely successful, and we have new partnerships to test our solar disinfection monitors in Kenya and Ghana. The team also took a few hours to see some sights and take photos.

PotaVida Team in D.C.Photo by Rick Roxburgh

Just after returning to MIT from the DC conference, Dr. Linnes was again on a plane, this time to Narobi, Kenya. There she worked with Melisa Menke, founder of Access Afya, which is building health clinics in the Mukuru slum in Nairobi. Currently, families in Mukuru have to pay for water daily from an untrusted water source piped in from outside the slum. Once Access Afya clinics are up and running, Access Afya would like to use the PotaVida monitor to ensure safe, solar-disinfected water is provided to patients, and to teach these same patients how to disinfect water in their homes.

Back in Seattle, the PotaVida monitor is being featured as a part of Global Health Month at the Next50 Celebration in Seattle. We are featured in the Experience Global Health Exhibit. The ribbon cutting was on July 2nd, and the exhibit is open to the public as of July 3rd. Come see our monitors in person!
Ribbon CuttingMaking Water Safe Display

MIT D-Lab Funding and New Partners

May 17, 2012 by PotaVida

Funding and Partners

As a start-up we are always seeking partners and funding- this month we got both! PotaVida is very pleased to announce that the MIT D-Lab awarded PotaVida a seed grant for field testing and market research over the next 9-12 months. The D-Lab is a group that focuses on developing and disseminating humanitarian technologies in developing countries.

Also coming from our partnership with D-Lab is a new collaboration with Cooper-Perkins, a technology and product development company that has offered pro-bono design work to PotaVida. We are very excited to be working with their team of mechanical and electrical engineers!

Next Generation Prototypes

We have begun production of a small batch of prototypes funded by this grant. We have ordered the new boards, and are working with World Vision to integrate these monitors into some of their existing disaster relief products. We'll keep you up to date on how this progresses.

Microbiological Testing in the Field

Finally, Fundacion SODIS, a Bolivia-based NGO which coordinates solar water disinfection training in Latin America will be including our prototypes in upcoming microbiological testing, which will provide an external validation of the efficacy of our product.

Thanks for reading!

-The PotaVida Team

UW BPC… Grand Prize and Best Innovation awards go to PotaVida

May 27, 2011 by PotaVida

Every year the University of Washington holds a Business Plan Competition (BPC) to identify the best idea with these four characteristics:

1) Best team
2) Best product
3) Most viable business
4) Deepest knowledge of market

This year 104 teams from 11 universities entered the competition. The teams were cut to the top 36 teams, then 16. Yesterday these 16 teams presented business plans to a panel of judges including venture capitalists, entrepreneurs, lawyers, and business owners.

PotaVida was judged to be the best team, and won the Grand Prize ($25K) and the Best Innovation ($2.5K) awards.

Thank you to all of the BPC staff, our advisers, especially Emer Dooley, Dave Jones, Craig Howard and Brian Strully. Also we could not have won without the support of Carbon Design Group.

Thank you!

Building the brand… PotaVida chooses a logo

February 14, 2011 by PotaVida

Graphic designer Sam Dawson heard about PotaVida in late December. Sam was impressed with the idea, enough to volunteer his time and skills to design a logo.

Due to travel and busy schedules we didn’t get a chance to meet with Sam until last week. Over a couple of mugs of coffee at Voxx on Eastlake we met to discuss logo ideas. We started simply with a list of ideas:
1) Sun
2) Water
3) Helping the poorest of the poor
4) We are making progress

From those we tightened our concept to a key phrase: “Safe water with certainty”.

We think that captures the essence of PotaVida: taking away the uncertainty of the SODIS process. In fact, we liked it so much we made it our new motto.

Sam took our motto, and the two hour conversation and created not one but 5 logos. Now we need to choose between these logos. And we need your help.

You can contribute your thoughts and make suggestions on each of the proposed logos at our FaceBook page. The logos are in the photos section and you can add comments there.

Thanks for your feedback, and thanks to Sam Dawson for his valuable contribution!


PotaVida on the radio!

December 22, 2010 by PotaVida

PotaVida member Charlie Matlack is interviewed on The Conversation with Ross Reynolds today, Wednesday, December 22nd on Seattle’s NPR station: KUOW 94.9 FM.

Students Win Prize For Clean Water Testing: A team of UW students invented a device that shows if water is safe to drink. The tool is called PotaVida, and the students were awarded $40,000 from the Rockefeller Foundation to manufacture it.”

Listen at KUOW.ORG
You can fast forward to 9m55s in the MP3 version.

Local News Covers PotaVida

December 21, 2010 by PotaVida

(Direct Link to King 5)

PotaVida Team Meets with PATH

December 21, 2010 by PotaVida

The UW team met with two staff of PATH’s Safe Water project in mid-November to discuss the UW team’s project. PATH is an international nonprofit organization whose vision is a world where innovation ensures that health is within reach of everyone. With headquarters based in Seattle, PATH was deemed a good local resource for feedback, especially regarding global health impact and appropriate technologies.

PATH shared with the UW team key findings gained from four years of research regarding household water treatment and safe storage products, including overviews of the HWTS landscape, barriers to uptake, targeted markets, identification of users, and applicability to different regions of the world. Although PATH is not endorsing the team’s product, the discussions led to a fruitful critique of areas for the UW team to investigate further. The Safe Water team is pleased to be able to provide feedback to local organizations and students and is proud of local endeavors aimed at reaching populations globally.

Learn more about PATH’s Safe Water Project

Students' Water-testing Tool Wins Design Contest; Launches Nonprofit

December 20, 2010 by PotaVida

Photo credit: Mary Levin, University of Washington

University of Washington engineering students have won an international contest for their design to monitor water disinfection using the sun's rays. The students will share a $40,000 prize from the Rockefeller Foundation and are now working with nonprofits to turn their concept into a reality.

Team member Jacqueline Linnes, who recently completed her bioengineering doctorate, traveled to Bolivia last year with the UW chapter of Engineers Without Borders. While there, she and other students treated their drinking water by leaving it in plastic bottles in the sun.

The concept is an old one. Solar disinfection of water in plastic bottles, also called SODIS, is promoted by many nonprofits. It offers a cheap and easy way to reduce some of the roughly 1.5 million diarrhea-related children's deaths each year. But global adoption has been slow, partly because it is hard to know when the water is safe to drink.

The UW entered a competition to design an indicator for Fundacion SODIS, a Bolivia-based nonprofit dedicated to testing and promoting this method. Solar disinfection in water bottles removes more than 99.9 percent of bacteria and viruses, with results similar to chlorination.

The UW device lets users know when the sun's rays have done their job.

Linnes began working on the problem with Engineers Without Borders members Penny Huang, a senior in chemical engineering, and Chin Jung Cheng, then an undergraduate in chemical engineering and now a UW doctoral student in bioengineering.

At first, the students focused on developing a chemical test strip. Then they considered an electronic sensor and contacted Charlie Matlack, a UW doctoral student in electrical engineering.

Together they built a system using parts from a keychain that blinks in response to light.

"It has all the same components that you'd find inside a dirt-cheap solar calculator, except programmed differently," Matlack said.

Other electronics monitor how much light is passing through the bottle and whether a water-filled bottle is present, so the system knows when to stop or start recording data.

Winning the contest means the students split the $40,000 prize, and their efforts may improve the health of children around the world.

"This is part of what engineering education should be," said faculty adviser Howard Chizeck, an electrical engineering professor. "It's educating students with the skills and the desire to make things better."

The competition was put on by InnoCentive Inc., a Boston-based company that since 2001 has hosted a website where organizations can post technical challenges with prize money and anybody can submit a solution.

In this case, even the challenges themselves were solicited on the web. GlobalGiving Foundation Inc., a Washington, D.C. nonprofit that acts as a clearinghouse for charitable donations, asked nonprofits around the world to submit technical challenges relating to water quality. It then chose four to post to InnoCentive, and the Rockefeller Foundation supplied prize money.

The Sodis Foundation evaluated more than 70 proposals before choosing the UW's.

"The evaluators appreciated the fact that the [UW] device takes into consideration factors like the material of the bottle and the turbidity of the water to be disinfected," said co-director Matthias Saladin. "Other factors favoring the proposal were its robust design, the long product life and its competitive price."

The challenge called for designs costing less than $10. The UW students estimate their parts would retail for $3.40, and bulk buying could reduce the cost further.

The Sodis Foundation now holds a nonexclusive license to develop the technology. It is also focusing on larger-scale systems that could be used in situations such as disaster relief. A Sodis Foundation donor has also offered Matlack $16,000 to continue developing a prototype of the water bottle indicator. (The contest proposal tested each part of the system separately.)

Over the next few months Linnes, Matlack and Tyler Davis, a doctoral student in the UW Evans School of Public Affairs, are setting up a nonprofit business to manufacture and market the device, either to users or to nonprofits that promote solar disinfection.

They have approached UW faculty and local nonprofits as potential partners, hoping to draw on a broad range of expertise.

"We're at a point where we recognize the need for work on this beyond engineering," Matlack said. "Ultimately, the hardest part is going to be to get people to use it."

PotaVida In The Press