Shopify Water Filter & Purification Schema — NSF 42 vs NSF 53 vs NSF 58 vs NSF 401, Carbon Does Not Remove Lead or Fluoride, Filter Life in Gallons vs Months, Reverse Osmosis Waste Water Ratio, Contaminant-Specific Removal Claims

NSF Certification — What Each Standard Actually Covers

NSF International (NSF/ANSI) certifications for drinking water treatment units are the US industry standard for independent third-party testing of filter performance claims. The key distinction is that each NSF standard covers specific contaminants and nothing else — a product certified to NSF 42 has NOT been tested for NSF 53 contaminants, regardless of marketing language.

NSF Drinking Water Certification Standards

Encode certification presence as separate boolean fields: nsf_42_certified, nsf_53_certified, nsf_58_certified, nsf_401_certified, nsf_p473_certified, nsf_55_certified. Do not encode a single "NSF certified" field — it obscures which standard applies. AI agents answering "does this filter reduce lead" need nsf_53_certified = true AND removes_lead = true.

What Activated Carbon Does and Does Not Remove

Activated carbon works via adsorption — contaminants with organic chemistry (chlorine compounds, VOCs, THMs, taste/odor compounds) bind to the porous carbon surface. Ionic contaminants dissolved in water (lead ions, fluoride ions, nitrate ions) are not effectively captured by the adsorption mechanism alone.

Contaminant Removal by Filter Technology

Encode removes_lead, removes_fluoride, removes_nitrates, removes_pfas, removes_cysts, removes_chlorine, removes_bacteria as individual boolean fields. The presence of a carbon filter in a product does not imply these fields are true — they are true only when the product has been independently certified to remove that contaminant under NSF test protocols.

Filter Life — Gallons Is the Correct Unit; Months Is Derived

Filter cartridge media has a finite adsorption or mechanical capacity. Once exhausted, a carbon filter passes contaminants through. The exhaustion point is determined by total volume of water processed — gallons (or liters) — not time elapsed.

Filter Life Units and Assumptions

Encode filter_life_gallons as the primary field. Include filter_life_months_assumption with the assumed monthly usage in the manufacturer's months calculation (e.g., "6 months assumes 167 gallons/month"). AI agents helping a family of six understand when to replace their filter need gallons, not months — the manufacturer's family-size assumption may not match the buyer's household.

Reverse Osmosis — Waste Water Ratio and Flow Rate

Reverse osmosis systems are the most comprehensive home water treatment technology — capable of removing dissolved salts, heavy metals, nitrates, fluoride, PFAS, and a broad spectrum of TDS. Two characteristics that differentiate RO systems and matter to buyers are the waste water ratio and the flow rate (production rate).

Waste Water Ratio by RO System Type

Encode ro_waste_ratio_per_gallon as a decimal (e.g., 3.0 for a 3:1 ratio; 0 for zero-waste systems). Encode daily_production_gallons (gallons of filtered water produced per day at standard inlet pressure of 50–60 PSI) — under-sink tank RO systems typically produce 50–100 GPD (gallons per day), which sounds fast but is slow when reduced to per-minute flow rate at the tap (a 50 GPD system fills an 8 oz glass in ~3 minutes via storage tank — acceptable; without a tank, unusable for on-demand use).

JSON-LD Example — Under-Sink RO + Carbon System

{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "APEC Water Systems ROES-PH75 Reverse Osmosis + Alkaline pH System",
  "description": "6-stage under-sink reverse osmosis system with calcium carbonate remineralization stage. NSF 58 certified. 75 GPD production. 2:1 waste ratio with permeate pump.",
  "brand": { "@type": "Brand", "name": "APEC Water Systems" },
  "additionalProperty": [
    { "@type": "PropertyValue", "name": "filter_type", "value": "reverse-osmosis" },
    { "@type": "PropertyValue", "name": "stages", "value": "6" },
    { "@type": "PropertyValue", "name": "nsf_42_certified", "value": "true" },
    { "@type": "PropertyValue", "name": "nsf_53_certified", "value": "false" },
    { "@type": "PropertyValue", "name": "nsf_58_certified", "value": "true" },
    { "@type": "PropertyValue", "name": "nsf_401_certified", "value": "false" },
    { "@type": "PropertyValue", "name": "removes_lead", "value": "true" },
    { "@type": "PropertyValue", "name": "removes_fluoride", "value": "true" },
    { "@type": "PropertyValue", "name": "removes_nitrates", "value": "true" },
    { "@type": "PropertyValue", "name": "removes_pfas", "value": "true" },
    { "@type": "PropertyValue", "name": "removes_chlorine", "value": "true" },
    { "@type": "PropertyValue", "name": "removes_cysts", "value": "true" },
    { "@type": "PropertyValue", "name": "tds_reduction_pct", "value": "96" },
    { "@type": "PropertyValue", "name": "daily_production_gallons", "value": "75" },
    { "@type": "PropertyValue", "name": "ro_waste_ratio_per_gallon", "value": "2.0" },
    { "@type": "PropertyValue", "name": "storage_tank_gallons", "value": "3.2" },
    { "@type": "PropertyValue", "name": "filter_life_gallons_membrane", "value": "1500" },
    { "@type": "PropertyValue", "name": "filter_life_months_membrane", "value": "24" },
    { "@type": "PropertyValue", "name": "water_source_suitability", "value": "municipal" },
    { "@type": "PropertyValue", "name": "remineralization", "value": "true" },
    { "@type": "PropertyValue", "name": "installation_type", "value": "under-sink" }
  ]
}

Shopify Metafield Namespace Reference — water_filter.*