We Tested 20+ Homes Across West LA for Microplastics — Here's the Map

Back in early 2025, I had a simple question: is there plastic in my tap water?

I live in West LA. I drink the tap water. I figured it was fine — LA's water system is massive, regulated, tested constantly. But microplastics aren't on any municipal test panel. Nobody was checking.

So I bought a fluorescence microscope, learned the Nile Red staining protocol used by the EPA and NOAA, and started testing. First my own water. Then my neighbors'. Then strangers on Reddit who wanted to know.

Here's what we found.

The Method

Every sample goes through the same process:

1. Collection — 100ml of tap water in sterile borosilicate glass vials (no plastic touches the sample)
2. Vacuum filtration — through a 0.45μm cellulose nitrate membrane
3. Nile Red staining — a fluorescent dye that selectively binds to synthetic polymers
4. Fluorescence imaging — under blue excitation light, plastic particles glow bright orange against a dark background

This isn't a home test strip. It's the same screening method used in peer-reviewed microplastic research. You can read the full methodology here.

The Results

We've now tested 20+ homes across West LA and surrounding neighborhoods. The results are published on the interactive map.

Every single sample contained microplastics.

The particle counts vary — some neighborhoods show 3-5 particles per 100ml, others show 15+. But zero? We haven't seen it yet.

Here's a neighborhood-by-neighborhood breakdown:

West Side

• Santa Monica — Moderate levels. The samples we've tested from Santa Monica consistently show microplastic particles, which is notable given the city's own water treatment infrastructure.
• Venice — Similar to Santa Monica. The older plumbing infrastructure in parts of Venice may be a contributing factor.
• Marina del Rey — Results in line with surrounding areas.
• West LA — Our home turf and most-tested area. Consistent moderate particle counts.
• Mar Vista — Comparable to West LA results.
• Westwood — Near UCLA. Moderate levels detected.
• Pacific Palisades — Even the Palisades aren't immune.

East Side

• Silver Lake — Some of the higher counts we've seen in our dataset.
• Echo Park — Similar to Silver Lake.
• Highland Park — Moderate to high.
• Los Feliz — Moderate levels.
• Eagle Rock — Results pending more samples.

South Bay

• Hermosa Beach — Moderate levels.
• Manhattan Beach — Similar to Hermosa.
• Redondo Beach — Moderate.

What Does This Mean?

Let's be honest: we don't know yet. There is currently no federal safety standard for microplastics in drinking water. The EPA doesn't regulate them. California is working on it — they were the first state to even define microplastics in drinking water — but enforceable limits are still years away.

What we do know:

• Microplastics have been found in human blood, lung tissue, and placental tissue
• Animal studies show inflammatory responses and cellular damage at high concentrations
• The smallest particles (nanoplastics) may be able to cross cell membranes
• Long-term human health effects are still being studied

The research is early. But the precautionary principle suggests that knowing what's in your water is better than not knowing.

Why This Project Exists

Municipal water reports test for lead, chlorine, bacteria, and dozens of regulated contaminants. But they don't test for microplastics. Nobody is mapping this data at the neighborhood level.

The Water Map is a community science project. We're building an open dataset of microplastic contamination in LA tap water, one sample at a time. Every result goes on the map. Nothing is cherry-picked or withheld.

Want to Test Your Water?

We sell $99 testing kits that include everything you need — sterile glass vials, prepaid return mailer, and lab analysis with fluorescence microscopy. Results are typically ready within 48 hours of receiving your sample.

Your results get added to the map (anonymized to neighborhood level), helping build the most detailed picture of microplastic contamination in LA's drinking water.

Order a test kit →

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This post was adapted from a discussion that reached 98k views on Reddit. The original post and community Q&A helped shape this project into what it is today.