Stockholm Junior Water Prize Project Ideas That Can Win

By Dr. Harman Brah, MD · Judge, California Science & Engineering Fair

The Stockholm Junior Water Prize projects that do well start with a real water problem and test what causes it or what fixes it, using real data and statistics. In 2026, state winners around the country studied topics such as phytoremediation, harmful algal blooms, stormwater and runoff filtration, biochar, constructed wetlands, cyanobacteria detection and wastewater pathogens.

That list is a map of where strong projects have landed. The idea that can win is the one your student builds from their own question inside one of those areas.

What the 2026 winners worked on

Look at the 2026 state winners as a group and a pattern shows up. Most of them took a known water problem, like nutrient runoff, algae or polluted stormwater, and tried to measure a cause or test a fix.

California is a good example. The state received 42 submissions in 2026, and the winner was a two-student team from Lynbrook High School in San Jose. Their project was on fertilizer pellets designed to cut the nutrient runoff that drives harmful algal blooms.

Third place in California went to a student at BASIS Independent Silicon Valley, also in San Jose, for a sensor project aimed at flood hotspots. Second place went to a team from Clovis North High School.

Notice what these share. Each one names a water problem people already live with and points the work at doing something about it.

Why cause and effect beats measurement alone

WEF’s national paper guidelines are direct about this. A project that only describes a problem ranks lower than one that explains what drives it and how the work helps solve it.

The judges give a lake example. A survey of a lake that is overloaded with nutrients and overgrown with algae, on its own, “will not be highly competitive.” The same survey becomes much stronger when it adds the causes of the problem and shows how monitoring could improve how the lake is managed.

So measuring something is a starting point. The stronger version asks why the number is what it is, or what changes it.

The guidelines add a few more pointers worth knowing before choosing a topic:

• If you are testing a solution, refer to earlier work and say what gap your project fills.
• If your project is about awareness, back it up with numbers, such as survey results.
• Explain how your project contributes to a solution, beyond describing the problem.

Relevance carries the most points

At the national level, six criteria are each scored from 1 to 5 and multiplied by a weight. Relevance has the heaviest weight, at five times, so it is worth up to 25 of the 115 points.

Relevance asks whether the project takes on an important challenge in the water environment, and whether it could improve the environment or people’s quality of life. That is why topics tied to a real local problem tend to read well.

The entry rules point the same way. Projects should aim to improve water quality, water resources management, or water and wastewater treatment, on a local, regional, national or global issue.

Turning a topic into the student’s own question

A topic is a place to stand. A question is something only your student can answer with their data.

Here is a simple way to get from one to the other:

1. Pick a water problem the student can see or name. Runoff after storms, algae in a local pond, drought, flooding on a certain street. Interest matters, because they will live with this question for months.
2. Ask what causes it, or what might reduce it. That turns a survey into an experiment, or a description into a test.
3. Decide what they can actually measure. WEF wants scientifically accepted methods for experimentation, monitoring and reporting, including statistical analysis.
4. Read what others have found. The guidelines ask students to show they know the literature, and a solution project needs to name the gap it fills.
5. Say who would use the result. The Discussion is where judges look for whether a local agency or the people affected could put the findings to work.

Water is a broad field. Water quality, treatment, runoff, algae, drought, stormwater, sensors and computational water models can all fit, as long as the project uses real data and statistics.

A judge’s view on picking a project

Dr. Harman Brah, a physician on our team, is a judge at the California Science & Engineering Fair. His advice on choosing a project carries over to water research:

• One clear question with real data beats an ambitious project with no result.
• Judges reward a student who can explain why each choice was made more than the most advanced technique.
• Controls and honest statistics are where most projects lose points.
• A project that looks parent- or mentor-built is seen through quickly.

That last point matters a lot here. The Practical Skills criterion asks what help parents, teachers and professionals gave, and whether the student carried out the measurements themselves.

The student does the work

The student chooses the question, runs the measurements and writes the paper. A mentor can help sharpen the question, check the statistics and push on the Discussion.

The paper’s acknowledgements should say clearly how much outside help there was. That honesty is expected and it protects the student.

When to start

The 2027 dates are not posted yet. In the 2026 cycle, state entries were due April 15, 2026, so most of the research and writing has to happen over the school year.

No science fair is required to enter. Any eligible student in grades 9 to 12 can self-nominate for their state competition online, alone or with one teammate. A student who already has a strong water-related science fair project has a head start, since this is a paper competition.

See our science fair and research mentorship, or read how to find a science fair project idea in high school.

FAQ

What kind of project wins the Stockholm Junior Water Prize?

There is no single winning topic. In 2026, state winners worked on areas such as phytoremediation, harmful algal blooms, stormwater and runoff filtration, biochar, constructed wetlands, cyanobacteria detection and wastewater pathogens. What they share is a real water problem and a research approach with data and statistics.

Is it enough for my child to test water quality somewhere?

Testing alone is a starting point. WEF’s judges say a project that only surveys a problem is less competitive than one that also looks at the causes and how the work could help manage or fix it.

Can my child use an existing science fair project for SJWP?

If it is a water project with real data, it can be a strong base. It is a paper competition, a science fair is not required to enter, and the student self-nominates for their state online.

Can two students do a Stockholm Junior Water Prize project together?

Yes. Students can enter alone or in a team of up to two. In 2026, California’s state winner was a two-student team.

What did California’s 2026 winner study?

The winning team, from Lynbrook High School in San Jose, studied fertilizer pellets designed to cut the nutrient runoff that drives harmful algal blooms. California received 42 submissions that year.