What's Actually in Your Tap Water? San Jose Contaminant Report

San Jose Water sends every customer a glossy "Consumer Confidence Report" once a year. It tells you the water meets all federal EPA standards. Every value is below the legal limit. The cover usually has a photo of a reservoir at sunset.

What it doesn't emphasize is that "meets federal standards" doesn't mean what you think it means. The legal limits are decades old. The Environmental Working Group sets independent health guidelines that are far stricter — and by those numbers, San Jose tap water has trihalomethanes at 274 times the recommended health guideline.

Here's what's actually in your tap water, what the city report doesn't highlight, and how to fix it.

"Meets federal standards" doesn't mean clean

The EPA's Maximum Contaminant Levels (MCLs) are the legal ceiling for what's allowed in drinking water. Two things to understand about them:

• They're decades old. The legal limit for trihalomethanes (a disinfection byproduct) hasn't been updated since 1998. Health science has moved on. The EPA hasn't.
• They're a compromise, not a safety target. MCLs are set based on what's achievable with current treatment technology and what's politically reasonable — not strictly on what's safe to drink for 70 years.

The Environmental Working Group (EWG) publishes parallel health guidelines based on the latest peer-reviewed cancer and toxicity research, ignoring political and cost factors. Comparing the two is illuminating:

• Trihalomethane legal limit: 80 parts per billion
• Trihalomethane EWG health guideline: 0.15 parts per billion

A 533× gap between "legal" and "what science says is healthy."

What's in San Jose tap water

Pulled from San Jose Water's most recent CCR plus EWG's tap water database for the San Jose service area:

Trihalomethanes (THMs) — Detected at 274× above the EWG health guideline. These are byproducts of chlorine disinfection reacting with organic matter in source water. Multiple studies link long-term THM exposure to increased risk of bladder, colon, and rectal cancer.

Haloacetic acids (HAAs) — Another disinfection byproduct, also above EWG guidelines. Same mechanism (chlorine + organic matter), similar concerns.

Hexavalent chromium (chromium-6) — The "Erin Brockovich" chemical. Detected in Bay Area drinking water at low levels. Carcinogenic in long-term exposure.

PFAS ("forever chemicals") — A family of industrial chemicals that don't break down in the environment or the human body. Detected in Bay Area stormwater and some drinking water sources. Linked to cancer, immune suppression, and developmental issues.

Chlorine and chloramine — Used to disinfect the water itself. Safe to drink at municipal levels, but causes the bleach-like taste and odor most people associate with tap water, and contributes to dry skin and brittle hair.

To be clear: San Jose tap water is legal to drink and won't make you sick today. The concern is cumulative, multi-decade exposure to compounds that exceed independent health guidelines. That's a different question than "is it safe" — and one a city water report isn't designed to answer.

What a reverse osmosis system removes

Reverse osmosis is the most effective residential filtration technology for the contaminants above. A 4-stage RO system pushes water through a semipermeable membrane with pores roughly 0.0001 microns wide — small enough to block dissolved chemicals that no carbon filter can catch.

Specific removal rates:

• PFAS: 90–99% removed
• Trihalomethanes: 99%+ removed
• Lead, chromium-6, dissolved solids: 99%+ removed
• Chlorine, chloramine: 99%+ removed (handled by carbon pre-filters before the membrane)

A 2025 EWG study highlighted what they call the "double benefit" of PFAS treatment: reverse osmosis systems installed to address PFAS also cut trihalomethanes and haloacetic acids by 42–50%. You're solving two problems with one install.

Do you need whole-home filtration or just drinking water?

Reverse osmosis at the kitchen sink handles every drop of water you drink, cook with, or use for ice and coffee. That's the highest-priority filtration target — anything you ingest.

A whole-home water softener handles the rest of your home: showers, laundry, appliances. It removes hardness minerals (calcium, magnesium) but doesn't filter chemical contaminants the way RO does.

The combination is why Lucid bundles them: an RO system at the sink for what you drink, plus a whole-home softener for everything else. Each system addresses a different problem the other can't. See how the Complete Home System works.

How to read your own water report

Two free resources every San Jose homeowner should bookmark:

• San Jose Water's annual CCR — Search "San Jose Water consumer confidence report" for the most recent year. Lists every contaminant detected, the legal limit, and the result.
• EWG's tap water database — Available at ewg.org/tapwater. Enter your zip code to see what's in your water compared to EWG's stricter health guidelines, not just the EPA's legal limits.

Compare the two and you'll have a much clearer picture of your tap water than the city CCR shows on its own.