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WaterQualityLens

Address-level water quality intelligence

Know exactly what’s in your tap waterand precisely what removes it.

Enter your address. We identify the utility that actually serves it, what it reports against federal limits, and the filters certified to remove it.

Dwelling type — tailors the hardware guidance
Try an example
  • EPA SDWIS enforcement data
  • NSF/ANSI certified hardware only
  • No account · no paywall
ZIP 48503POINT-IN-POLYGON · TIER 1

PWS MI0002360

Lead (Pb90)27 µg/L

180% of MCL15 MCL

Sampled 2026-05-15 · EPA SDWIS

  • EPA SDWIS dataEnvirofacts API · weekly refresh
  • TEMM address-level boundariesEPA polygons, July 2024 · TEMM layers
  • Independent NSF/ANSI verificationNSF · WQA · IAPMO · audited quarterly
  • No fear-based ratingsFederal MCLs · no proprietary scores

How it works

From an address to a verified answer in three steps

The same deterministic pipeline runs for every address: identify the system, read the record, match the hardware. No account, no upsell in the way of the data.

  1. 01

    Enter your address

    We geocode your address and resolve the public water system that serves it using TEMM utility-boundary polygons — not a ZIP code. Every match is graded on a three-tier confidence scale, so you always know how certain the result is.

    Point-in-polygon
  2. 02

    See your utility’s reported contaminants

    We surface the contaminants your utility has reported to the EPA, each shown with its sample date, testing agency, unit, and the legal maximum contaminant level (MCL). Every number carries its source — no naked figures, no proprietary scores.

    Full provenance
  3. 03

    Get the exact certified filters

    We match the specific retail filter SKUs that hold independent NSF/ANSI certification for your contaminants — and flag the standards that don’t apply, like carbon filters that cannot remove nitrate. The recommendation follows the data, never the other way around.

    SKU-level

Why we’re different

An auditor’s standard, not an advocacy pitch

Most water-quality tools are built to alarm or to sell. We report the public record against the legal standard and point you to independently verified hardware — whoever makes it. Here is how that compares to the common approaches.

Location precision

WaterQualityLens: Address-level utility boundaries (point-in-polygon)
Common approaches: ZIP codes, which routinely span several different utilities

How limits are set

WaterQualityLens: EPA legal limits (MCLs) shown plainly, with sample provenance
Common approaches: Proprietary thresholds well below any regulatory standard

Filter verification

WaterQualityLens: SKU-level, independent NSF/ANSI certification for each contaminant
Common approaches: Broad brand affiliate links, not verified per-contaminant SKUs

Commercial incentive

WaterQualityLens: Vendor-agnostic — we don’t manufacture or sell any filter
Common approaches: Some diagnostic sites sell the very filter they recommend

Coverage & rigor

Grounded in public data and independent standards

Every figure here is derived from the dataset this site runs on. We track regulated contaminants, audit the NSF/ANSI standards that actually govern removal, and grade each address match on a transparent confidence scale.

27 regulated contaminants tracked

One cell per contaminant in the tracking set, grouped by class. A solid cell marks a contaminant whose EPA health goal (MCLG) is zero — 14 of 27 carry one.

  • Metals8
  • PFAS6
  • Inorganics3
  • VOCs3
  • DBPs2
  • Microbial2
  • Radionuclides2
  • Pesticides1
  • MCLG = 0 (14)
  • Numeric MCLG (13)

5 NSF/ANSI standards audited

How far each standard actually reaches across the tracked set, counting only contaminants a certified filter covers under a health claim. Two of the five reach nothing.

  • NSF/ANSI 5818 of 27

    Reverse osmosis — dissolved inorganics

  • NSF/ANSI 5310 of 27

    Carbon block — health reduction

  • NSF/ANSI 4013 of 27

    Emerging & incidental compounds

  • NSF/ANSI 420 of 27

    Aesthetic only — no health-removal claim

  • NSF/ANSI 3720 of 27

    Materials only — no removal claim

Coverage reflects the certifications held by filters in our audited registry, not the full theoretical scope of each standard.

11
Verified filter SKUs
Certification checked per contaminant
3-tier
Address-mapping confidence
Explicit, matched or modeled — always labeled

The distinction that drives everything

Not all certifications mean what the box implies

The NSF/ANSI standard printed on a filter tells you what it is actually proven to do. Confusing an aesthetic or materials standard for a health one is the single most common way shoppers overpay for protection they don’t get.

NSF 42Taste & odor

Aesthetic, not health

Reduces chlorine taste, odor, and particulates. It makes water more pleasant — but a 42-only filter is not certified to remove any health contaminant.

NSF 53Lead · VOCs · PFAS

Health contaminants

The core health standard for point-of-use carbon filters: lead, many VOCs, cysts, and (post-P473) PFAS reduction — verified to defined limits.

NSF 58Nitrate · arsenic · total PFAS

Reverse osmosis

Governs reverse-osmosis systems that remove dissolved inorganics carbon cannot — nitrate, arsenic, hexavalent chromium, and total PFAS.

NSF 372Often misread

Lead-free materials

Certifies the filter’s own materials are lead-free — a manufacturing claim, not a removal claim. It is frequently displayed to imply lead removal it does not provide.

Explore the Filter RegistryContaminant glossary

See your water’s record in under a minute

Enter your address to identify your utility, review what it reports, and find the exact certified filters for your contaminants. Free, and no account required.

Dwelling type — tailors the hardware guidance

WaterQualityLens aggregates public water-system engineering data and hardware certifications. It does not diagnose exposure, predict health outcomes, or provide medical advice.