Water quality
St. Louis water is technically safe. Here's why we still recommend filtering it.
Both the City of St. Louis Water Division and Missouri American Water meet every federal Safe Drinking Water Act standard. The federal limits were last updated in 1998. The science of cancer risk has moved on, and so should your drinking water.
The four categories
What's actually in St. Louis tap water.
Contaminants in our water fall into four chemically distinct families. Each family requires a different filtration mechanism. No single common consumer technology except multi-stage RO addresses all four.
Heavy metals
Lead from service lines and brass fittings, copper, chromium-6, occasional arsenic in well water. Heavy metal ions are dissolved in water, they cannot be filtered out by carbon alone.
What it takes to remove: Reverse-osmosis membrane (0.0001-micron pore size) physically excludes dissolved metal ions from the water you drink.
- 9,000+ confirmed lead service lines in the City of St. Louis; ~58,000 lines of unknown material still being surveyed.
- St. Louis tap chromium-6 averages ~1.6 ppb, about 80× California's public-health goal of 0.02 ppb.
- Even homes without a lead service line can have lead from pre-1986 brass fittings, lead-soldered copper joints, or galvanized plumbing.
Disinfection byproducts (DBPs)
Trihalomethanes (TTHMs) and haloacetic acids (HAA5/HAA9) form when chlorine or chloramine reacts with naturally occurring organic matter in source water. They're an unavoidable side effect of safe disinfection.
What it takes to remove: Activated carbon (adsorption) at the pre-filter and post-filter stages of an RO system removes 95–99% of DBPs at the tap.
- St. Louis TTHMs measure ~15.3 ppb, below the 80 ppb federal limit, ~102× the EWG health-based guideline of 0.15 ppb.
- HAA9 levels run ~405× the EWG guideline. There is no federal MCL for HAA9.
- Long-term exposure has been linked to bladder cancer, colorectal cancer, low birth weight, and preterm birth.
Forever chemicals (PFAS)
Per- and polyfluoroalkyl substances are a family of ~14,000 synthetic chemicals used since the 1940s. They are called 'forever chemicals' because the carbon-fluorine bond does not meaningfully break down in water or in the human body.
What it takes to remove: RO membrane plus activated carbon. Granular activated carbon alone is partial. Pitcher filters do not address PFAS.
- St. Louis 2024 UCMR-5 monitoring reported non-detects for all 29 PFAS compounds tested. That's genuinely good news, and we report it honestly.
- PFAS contamination is geographically unpredictable. The St. Louis region sits in an industrial corridor with multiple historical PFAS sources.
- EPA finalized the first-ever federal MCLs for six PFAS in April 2024 at 4 parts per trillion, recognition that prior 'safe' levels were vastly too high.
Chloramine (taste & breakdown)
The City disinfects with chloramine (chlorine + ammonia) instead of chlorine alone. Chloramine is more stable than chlorine, which is why larger municipal systems use it, and why it doesn't dissipate from a pitcher in the fridge.
What it takes to remove: Catalytic activated carbon, not standard granular carbon. This is the difference between a system that 'fixes the taste' and one that actually does.
- Chloramine is the #1 driver of 'tap water tastes bad' complaints in the City. It carries through to coffee, tea, ice cubes, soup stock, and baby formula.
- Cheap RO systems and almost all pitcher filters use standard carbon and quietly fail to deliver on the chloramine promise.
- Catalytic carbon is a deliberate component of every Water Co System install, it's what makes the coffee actually taste different.
Filter comparison
Pitcher vs. faucet filter vs. whole-home carbon vs. RO.
The punchline: a properly specified 5-stage under-sink RO system is the only consumer-grade point-of-use technology that meaningfully addresses every contaminant family present in St. Louis water.
| Technology | Lead | DBPs (TTHMs/HAAs) | Chromium-6 | PFAS | Chloramine taste | Typical cost |
|---|---|---|---|---|---|---|
| Brita-style pitcher (carbon) | $30 + filters | |||||
| Faucet-mount (PUR, etc.) | $30–$100 + filters | |||||
| Refrigerator filter | $50–$100/yr | |||||
| Whole-home carbon | $1.5–$3K | |||||
| Water softener (ion exchange) | $1.5–$4K | |||||
| 5-stage under-sink RO | $1,200–$1,800 installed |
Sources: NSF/ANSI Standard 42, 53, 58, 401 + P473 certifications; EPA Point-of-Use Reverse Osmosis Systems documentation; manufacturer test reports; EWG Water Filter Buying Guide.
The honest case
Six things parents should know.
None of these claims require exaggeration. The science is more than enough to make the case, and every claim survives a fact-check.
“There is no safe level of lead for a child.”
The CDC, the American Academy of Pediatrics, and the EPA all agree that no amount of lead exposure is safe for a developing child. Children under 6 absorb roughly 4–5× more ingested lead than adults do.
“Federal water limits were last updated in 1998.”
St. Louis water is in full compliance with limits that haven't been revised in nearly three decades. EWG analyses show contaminants at 100–400× current health-based guidelines for cancer risk.
“Brita removes the taste, not the chemicals.”
A standard pitcher filter is a taste filter. It is not designed to remove disinfection byproducts, heavy metals, or forever chemicals. The difference is freshening the air vs. actually filtering it.
“Hot showers are a TTHM exposure pathway.”
TTHMs vaporize in hot water and are inhaled and absorbed through skin. Long-term exposure during pregnancy has been linked in peer-reviewed studies to low birth weight, preterm birth, and increased miscarriage risk.
“Cloudy ice is a daily reminder.”
The cloudiness in tap-water ice is dissolved minerals and microbubbles. RO water freezes clear. It's the proof your kids will notice every day, and the reason the ice add-on is in our menu.
“Your child drinks the water you give them.”
Pediatric guidance is to make children's drinking water the cleanest you reasonably can. RO at the kitchen sink, and tied into the fridge dispenser, is the cleanest practical option for a household.
Free, in 60 seconds
Get the report for your specific address.
Pulled from your utility's most recent Consumer Confidence Report and compared to current EWG health-based guidelines. We never imply your utility is breaking the law, they're not. We just show you what 'legal' actually means.