PJURE™ Technical Documentation

This technical white paper describes the design, materials, filtration mechanisms and scientific basis of the PJURE stainless steel under-sink water filtration system.

The purpose of this document is transparency.

Rather than relying on marketing language or wellness claims, this paper explains how the filtration system is constructed, what each filtration layer is designed to do, which standards inform its evaluation, and how independent scientific research supports the underlying filtration principles.

This document does not replace regulatory certification. It provides technical context for how the system works and how its design aligns with established drinking water treatment practices.

PJURE is a multi-stage, under-sink water filtration system designed for everyday drinking water use in European households.

At a glance

• Tested on PJURE: at least 97% free-chlorine reduction through the full rated capacity of 30,000 litres — tested to NSF/ANSI 42 by an independent, ISO/IEC 17025-accredited laboratory (section 4.3).
• Materials: water-contact materials meet NSF/ANSI 372 (lead-free), per the manufacturer's certification. Copper and zinc release from the KDF stage stayed below 0.3% of the NSF/ANSI 42 limits.
• Based on the technology, not tested on PJURE: activated carbon is widely studied for reducing PFAS, VOCs and disinfection by-products. We do not publish a PJURE figure for these until we have our own test.
• Not claimed: bacteria or viruses, fluoride, nitrate, hardness or softening, microplastics.

The filtration assembly is housed in stainless steel and consists of the following sequential layers:

1. Non-woven PET pre-filter
2. Activated carbon block (coconut shell based)
3. KDF media (copper–zinc alloy)
4. Polypropylene (PP) membrane
5. Mineralizing media (calcite and maifanite)

Each layer performs a defined function. No single filtration medium is intended to address all contaminant categories alone. PJURE is designed for water that is already safe to drink.

Material: Polyethylene terephthalate (PET)
Filtration accuracy: ~200 microns
Function: Mechanical interception of large particles

The first filtration stage captures coarse particulate matter such as sand, rust and sediment. This protects downstream filtration media from fouling and extends overall system lifespan.

Non-woven PET media is used in drinking-water pre-filtration because it is mechanically stable and chemically inert. This layer does not alter water chemistry.

Material: Coconut shell activated carbon with UHMWPE binder
Filtration accuracy: ~3 microns
Filtration mechanism: Adsorption

Activated carbon reduces contaminants through adsorption: dissolved organic molecules bind to the very large internal pore structure of the carbon. The block design ensures consistent contact time and reduces channeling.

What this stage is designed to reduce

• residual chlorine — tested on PJURE (section 4.3),
• taste and odour compounds,
• volatile organic compounds (VOCs) and disinfection by-products — based on the technology, not tested on PJURE.

Why chlorine matters for taste: the WHO Guidelines for Drinking-water Quality note that some people can taste chlorine at concentrations as low as 0.3 mg/L.

PFAS: the EU rules and the research

EU rules. Since 12 January 2026, tap water in the EU must stay below 0.1 µg/L for the sum of 20 PFAS, or 0.5 µg/L for "PFAS total" where a member state uses that parameter (Directive (EU) 2020/2184). Germany adds a stricter limit of 0.02 µg/L for four PFAS from 2028 (German Environment Agency, UBA). The European Food Safety Authority set a tolerable weekly intake of 4.4 ng per kg of body weight for four PFAS combined (EFSA, 2020). The European Environment Agency describes PFAS pollution as widespread in Europe (EEA), and the EU is assessing a restriction of PFAS as a group (ECHA). In the US, the EPA set limits of 4 ng/L for PFOA and PFOS in 2024 and lists granular activated carbon as an effective treatment (US EPA fact sheet).

What this means for you. Your public water supplier must test for PFAS and meet these limits. A home filter is an optional extra step, not a replacement for that. Your supplier's latest results are usually published on its website.

What research shows about carbon filters. In a study of filters in real homes, activated-carbon point-of-use filters reduced PFAS by 73% on average, with wide variation; reverse-osmosis and two-stage under-sink filters reached at least 94% (Herkert et al., 2020, Environmental Science & Technology Letters). A 2024 study of 75 PFAS found removal from about 20% to almost 100% depending on the filter and the water, with short-chain PFAS harder to remove (Teymoorian et al., 2024, Frontiers in Environmental Chemistry).

PJURE's position. PJURE uses a coconut-shell activated carbon block, but it has not been tested for PFAS, so we do not state a PFAS reduction figure. We will publish independent results here when we have them.

Material: KDF 55 — high-purity copper and zinc alloy (approximately 1:1)

Filtration mechanism: Oxidation-reduction (redox) reactions

As water flows through the granules, electrons transfer between the metal and dissolved substances. Free chlorine is converted to chloride (KDF Fluid Treatment, manufacturer documentation). In PJURE, this stage reduces the chlorine load before the water reaches the carbon block. KDF does not adsorb contaminants and is not a physical filter.

Measured metal release

Because this stage contains copper and zinc, the independent laboratory also measured what it releases (NSF/ANSI 42, §6.9). Across 30,000 litres, copper in the filtered water was at most 3.1 µg/L and zinc at most 9.4 µg/L — under 0.3% of the standard's limits (1,300 µg/L copper, 3,000 µg/L zinc), and far below the EU tap-water limit for copper of 2.0 mg/L (Directive (EU) 2020/2184, Annex I).

KDF media is also used in water treatment to reduce some dissolved metals; this has not been tested on PJURE. We make no antibacterial claim for this or any other stage.

Material: Food-grade polypropylene

Filtration accuracy: ~25 microns

Function: Fine particle interception and polishing

This membrane captures residual particles and carbon fines released from upstream filtration stages. It improves water clarity, stabilizes flow and protects the mineral media.

Polypropylene is commonly used in drinking water systems due to its chemical stability and low extractables (European Commission: food contact materials).

Microplastics. The EU adopted a common method for measuring microplastics in drinking water in 2024 (Delegated Decision (EU) 2024/1441). PJURE's pre-filter and PP membrane capture particles mechanically, but the cartridge has not been tested for microplastics, so we make no microplastics claim.

Materials: Calcite and maifanite

Function: Mineral balance and taste

PJURE contains no ion-exchange resin and no reverse-osmosis membrane — the two technologies that remove calcium and magnesium. Jug filters with ion-exchange resin make water softer and lower in minerals (Stiftung Warentest, 2022). PJURE keeps the calcium and magnesium already in your water.

• Calcite can add a small amount of calcium and raise pH slightly.
• Maifanite is a porous silicate mineral traditionally used in water treatment for taste balance.

This stage does not add synthetic electrolytes and does not deliver a nutritional dose. Background reading: WHO, Calcium and Magnesium in Drinking-water.

What is tested, and what is not:

• Tested on PJURE: chlorine reduction and copper/zinc release, to NSF/ANSI 42 (section 4.3).
• Materials: lead-free materials to NSF/ANSI 372, per the manufacturer's certification.
• Not tested on PJURE: PFAS, VOCs, dissolved metals, microplastics, microbiological performance.

We describe untested substances only in terms of the technology and independent research, and say so in the same place.

PJURE's chlorine performance is documented by two tests:

• Independent laboratory test (2022–2023): two cartridges run to the full rated capacity of 30,000 litres to NSF/ANSI 42 by an ISO/IEC 17025-accredited laboratory in the United States. At least 97% reduction at every sampling point.
• Production quality check (January 2025): carried out by the manufacturer using the NSF/ANSI 42 method, through 3,000 litres. 98.4–99.4% reduction.

Two results two years apart show consistent performance from production batch to production batch.

Independent test overview:

• Laboratory: independent, ISO/IEC 17025-accredited, United States
• Standard: NSF/ANSI 42-2021, §7.3.3 (chlorine reduction) and §6.9 (active agent: copper and zinc release)
• Dates: 29 December 2022 – 2 February 2023
• Units tested: 2
• Influent free chlorine: 2.0 mg/L (average), pH 7.5, 20 °C
• Flow rate: 3.8 L/min (1 gpm), 50% on / 50% off cycle
• Total volume: 30,000 litres (8,000 US gallons) — the cartridge's full rated capacity

• The tests cover chlorine reduction and the release of copper and zinc. They do not cover PFAS, metals in the incoming water, microplastics or microorganisms.
• "At least 97%" is the most the data can show: the filtered water was below the laboratory's 0.05 mg/L reporting limit at every point.
• Results reflect controlled laboratory conditions. Actual performance may vary with local water quality and use.

All materials used in the PJURE filtration system are selected for long-term stability, durability and suitability for contact with drinking water.

The stainless steel housing is corrosion-resistant and designed for extended service life. Polymer components are food-grade, BPA-free, and selected for low extractables and chemical inertness.

Lead-free materials (NSF/ANSI 372). The system's water-contact components meet NSF/ANSI 372, according to the manufacturer's certification documentation. The standard limits the weighted-average lead content of all surfaces in contact with drinking water to 0.25% or less. It covers the materials themselves, not the reduction of lead already in tap water.

Metal release. Copper and zinc release from the KDF stage stayed below 0.3% of the NSF/ANSI 42 limits over 30,000 litres (section 3.3).

The filtration principles applied in the PJURE system are based on established drinking water treatment science.

Each filtration layer corresponds to mechanisms widely documented in peer-reviewed research and public health guidance, including adsorption, redox reactions, mechanical interception and mineral stabilization.

Rather than introducing experimental or proprietary treatment concepts, PJURE applies conservative, well-understood technologies in a multi-stage configuration supported by independent scientific literature.

The cartridge is rated for 30,000 litres or 12 months, whichever comes first. The independent chlorine test ran to the full 30,000 litres (section 4.3).

Pre-filtration reduces particulate load, KDF media reduces the chlorine load on the carbon, and block carbon construction minimizes channeling. Actual lifespan may vary depending on source water quality and daily water usage.

Hygiene

Any filter that holds water can develop bacterial growth over time. Stiftung Warentest found germs in every jug filter it tested after a simulated holiday absence (test.de, 2022). So: flush for 5 minutes after installing a new cartridge, run the water for 30 seconds after a few days away, and replace the cartridge on time.

What PJURE does not do

It does not disinfect or make unsafe water safe to drink, soften water, remove fluoride, nitrate or sodium, or replace testing of a private well.

Standards. Chlorine reduction and copper/zinc release are tested to NSF/ANSI 42. Water-contact materials meet NSF/ANSI 372 (lead-free), according to the manufacturer's certification documentation. PJURE is not certified to NSF/ANSI 53, 58 or 401.

European framework. Drinking-water quality in the EU is set by Directive (EU) 2020/2184. Materials in contact with food are covered by the EU food contact materials framework (European Commission). New EU hygiene rules for materials and products in contact with drinking water apply from the end of 2026 (European Commission: drinking water).

We describe certification status exactly as it is, and do not imply certification where there is none.

PJURE's filtration system uses established drinking water treatment technologies. What has been tested on PJURE is stated as tested; what is based on the technology and independent research is stated as such, with the source linked in the text.

Clean water does not require marketing language. It requires documentation.

Written by Annette Holst, founder · Version 3.0 · Updated 23 October 2026

• Directive (EU) 2020/2184 on the quality of water intended for human consumption — EU
• EFSA (2020). Risk to human health related to the presence of perfluoroalkyl substances in food — EU
• EEA. Emerging chemical risks in Europe — PFAS — EU
• ECHA. Per- and polyfluoroalkyl substances (PFAS) — EU
• Umweltbundesamt. New Drinking Water Ordinance — Germany
• Delegated Decision (EU) 2024/1441: methodology to measure microplastics in drinking water — EU
• Stiftung Warentest (2022). Wasserfilter im Test — Germany
• European Commission. Food contact materials — EU
• Herkert NJ et al. (2020). Assessing the effectiveness of point-of-use residential drinking water filters for PFASs. Environ. Sci. Technol. Lett. 7(3):178–184
• Teymoorian T et al. (2024). Performance of pitcher-type POU filters for the removal of 75 PFAS. Front. Environ. Chem. 5:1376079
• US EPA (2024). PFAS National Primary Drinking Water Regulation: treatment fact sheet
• WHO. Guidelines for Drinking-water Quality, 4th ed.
• WHO. Calcium and Magnesium in Drinking-water
• NSF. NSF/ANSI 42, 53 and 401 filtration system standards
• NSF. NSF/ANSI/CAN 372 technical requirements
• KDF Fluid Treatment. KDF process media (manufacturer documentation)