Senior Water Researcher

GiveWell’s mission is to help people in need as much as we can by researching the most cost‑effective ways to save and improve lives, sharing our work openly, and directing donations to the programs we believe will do the most good. Our work, which focuses on global health and well-being, is funded by tens of thousands of donors who rely on our research to inform their giving. We’ve grown from directing $1.5 million in 2010 to directing more than $400 million in 2025. We anticipate our total grantmaking is likely to approach or even exceed $1 billion this year, and we are working toward a future that could be several times that scale. Through years of deliberate groundwork, we’ve been growing our research capacity and scope in order to direct substantially more funding to the most impactful opportunities we can find.

Summary GiveWell is seeking a Senior Water Researcher to help direct tens of millions of dollars annually to the most cost-effective water interventions we can find. You will have an outsized influence on our funding decisions and help us save and improve lives on a global scale.

Our water grantmaking has historically focused on improving drinking water quality through chlorination — primarily chlorine dispensers and in-line chlorination — in low- and middle-income countries with a high burden of waterborne disease. In 2025, we ran a public Request for Information (RFI) that resulted in 18 pilot grants to 12 implementing partners across six African countries, totaling roughly $20 million. In 2026, we are beginning to pivot from a narrow focus on chlorination toward a broader exploration of the water sector. This includes investigating alternative water quality interventions (e.g., filtration, in-line ultraviolet disinfection, chemical contamination remediation), different clean water delivery models (e.g. diarrheal outbreak prevention and response, safe water enterprises), exploring water access and infrastructure layering with multilaterals such as the World Bank, market shaping for chlorine supply chains and measurement technology, and R&D for hardware and better service delivery models.

As a Senior Water Researcher, you'll create and lead ambitious research agendas related to our portfolios of work and answer complex questions that will inform GiveWell's grantmaking decisions. The researchers on our team combine rigorous evidence review, cost-effectiveness modeling, and thoughtful judgment.

We're open to a wide variety of professional development pathways depending on your preferences and our needs.

The role You will be joining a small grantmaking team to contribute to our ambitious research agenda on water. You'll sift through the countless questions we could try to answer, and hone in on those that matter most. You'll also communicate externally about your work and mentor and advise other researchers on the team. You will shape a research agenda that brings rigor and creativity to the thorniest questions the GiveWell water team faces. Your work will combine empirical evidence review and critical synthesis, cost-effectiveness modeling, discussions with subject matter experts, understanding of the broader context, and your own judgment.

What you might work on in your first year: - How should we calibrate our cost-effectiveness estimates to real-world program performance? - How does chlorination compare with alternative water quality methods — such as filtration, in-line UV, and chemical contamination remediation — across different settings? Where, if anywhere, are these alternatives more cost-effective? - Can GiveWell unlock large amounts of cost-effective room for more funding by partnering with multilaterals (e.g. the World Bank) to layer water treatment onto large-scale piped water infrastructure projects? What are the practical and political constraints? - To what extent should our portfolio shift between water quality (our current focus) and water access? Are there access-related grantmaking opportunities — for example, supporting direct delivery of clean water, water kiosks, or boreholes paired with treatment — that meet our cost-effectiveness bar? - How do we improve our estimate of the all-cause mortality effect of chlorination on children under-5? - How should we use new funding mechanisms — such as regranting, prizes, and a possible Water Incubator with implementing partners — to identify and scale promising interventions?

The Senior Water Researcher will help shape a major annual grantmaking portfolio, own grant investigations end-to-end (from research question through grant recommendation), and represent GiveWell to external counterparts. You'll have significant latitude to propose new areas of work.

Team structure Our research department has over 60 people, and is currently organized into eight teams: - Five of the teams (Livelihoods, Malaria, Nutrition, Vaccination, and Water) focus on specific areas of grantmaking. - The New Areas team focuses on interventions in domains that are new to GiveWell. - The Cross-Cutting team focuses on methodological issues, research quality, and other big-picture concerns that cut across all of our research work. - The Commons team provides generalized research support to each of the other teams, including landscaping research, vetting, and publishing. - There are currently three people on our water team.

Team values We think our research team has unique qualities: - We care deeply and centrally about finding and sharing truth. Truth-seeking is one of our core values. We post our mistakes and we prize our team members who keep our culture of free-flowing feedback strong. - We are independent. We focus 100% on finding the most cost-effective opportunities to save and improve lives. Our researchers assist in communicating our research findings to the public and our donors, and on occasion we provide tailored advice to ultra-high-net-worth donors who want to rely on our expertise to direct their giving—but we never ask our researchers to trade off against honesty, or to hide their real beliefs. - We don’t waste time. Once it’s clear that a particular research question is unlikely to change our bottom-line funding recommendation, we drop it as quickly as possible. We encourage our research staff to constantly re-evaluate their portfolios and only work on the highest-priority questions. - Lean research team = huge personal impact. In 2022, we directed about $440 million with a research staff of less than 40 people. - We work well together. Our research team is lean because we’re able to attract top-tier people, all of whom complete skills-based assessments before joining our staff. We maintain a high-performing, collegial culture and pay our staff accordingly.

About you We expect the Senior Water Researcher to have - A quantitatively oriented advanced degree (e.g., in epidemiology, environmental engineering, environmental health, public health, economics, or related fields). - Substantial professional experience in the water sector or an adjacent field (broadly defined). This could include experience in water quality, WASH, water infrastructure, environmental health modeling, or in program implementation, evaluation, or funding. We're especially interested in candidates with hands-on familiarity with water systems, epidemiology, or both. We don't expect any single candidate to have deep expertise across all of the areas we're exploring (chlorination, filtration, in-line UV, water access, market shaping, R&D), and we're happy to consider strong researchers whose expertise sits in any subset of these.

We expect that people with the soft qualities below will be the most successful and happy on our team. This isn’t a full list, but hopefully it conveys the gist of our team’s professional personality: - GiveWell’s mission and methods are personally energizing—you like our approach to research and you find personal meaning in our story of impact. - You’re abnormally curious—you ask lots of questions, and you’re willing to interrogate others’ work. Your curiosity also extends to your own work—you aren’t defensive when your research comes under scrutiny. - You routinely think about and surface the value judgments, background knowledge, and strategic commitments that undergird your work. You understand the potential effects of mistaken mental models, so you strive to improve yours and your team’s. - You dislike it when people express strong confidence in views that don’t seem to rely on commensurate evidence. You carefully and legibly communicate about your confidence levels. - You appreciate the value of an excellent reputation and strong relationships. You can moderate your directness and intensity when you’re communicating with external folks. - You love a gnarly problem. You figure out the most important questions to answer, go deep on the details where they matter (and move on where they don’t), and reassess your mental models based on what you’ve learned. - You constantly assess whether you and the team are working on the most important things.