Whole House vs. Gravity Filter
Mam Nature Swiss vs. Berkey
Berkey is a popular gravity-fed countertop filter, especially in off-grid and preparedness communities. But a countertop gravity filter and a whole-house point-of-entry system serve fundamentally different purposes. This comparison clarifies what each can and cannot do — using publicly available data and independent certifications.
The fundamental difference: coverage and certification
Berkey is a countertop gravity filter for drinking water only. Mam Nature Swiss is a whole-house system that protects every tap, shower, and appliance with ETH Zurich certified contaminant removal. PFAS and chlorine enter the body through skin and steam — not only through drinking. A countertop filter addresses one route; a whole-house filter addresses all of them.
Not a substitute for whole-house filtration.
Side-by-Side Comparison
| Criterion | Mam Nature Swiss | Berkey (Gravity Filter) |
|---|---|---|
| Coverage | ✓ Whole house (all taps + shower) Point-of-entry installation at the main supply line. Every litre entering the home is filtered — drinking, cooking, bathing, and laundry. | – Countertop only (drinking water) Gravity-fed countertop unit. Treats only the water poured into the upper chamber. Shower, bath, and appliance water is unfiltered. |
| PFAS removal | ✓ 95–99.9% (ETH Zurich) Independently certified by ETH Zurich (ISO/IEC 17025) for the full PFAS spectrum, including short-chain PFAS (PFBS, PFHxA). | – Claimed but not independently certified Berkey claims >99.9% PFAS reduction based on internal testing. No independent third-party certification from NSF, ETH Zurich, or equivalent accredited laboratory has been published for full-spectrum PFAS removal. |
| Heavy metal removal | ✓ 95–99% (ETH Zurich) Lead, copper, arsenic, cadmium, chromium, aluminium — independently tested and certified. | – Claimed >99% (internal data) Berkey claims high heavy metal reduction rates. These figures are based on internal or commissioned testing, not independent accredited laboratory certification. |
| Flow rate | ✓ Up to 2,000 L/hr No restriction on household flow. Full water pressure maintained across all appliances, showers, and taps. | – ~3–7 L/hr (gravity-fed) Gravity filtration is inherently slow. A Royal Berkey with two Black Berkey elements produces approximately 3–7 litres per hour depending on water temperature and element age. |
| Regulatory compliance | ✓ CE marked · Swiss Safety Center · ISO 13485 Full European regulatory compliance. Swiss Safety Center certified. Hydrogen Booster holds Class 1 Medical Device certification. | – EPA stop-sale history (2023) In 2023, the US EPA issued a stop-sale order for Berkey products over unsubstantiated pesticide device claims. Berkey has since resumed sales, but the regulatory history is notable. Berkey does not carry NSF certification for most models. |
| Independent certification | ✓ ETH Zurich (ISO/IEC 17025) ETH Zurich — one of the world's top-ranked engineering universities — independently verified filtration performance under controlled conditions. | – No NSF or equivalent certification Most Berkey models do not carry NSF/ANSI certification. Performance claims are based on internal or commissioned testing rather than independent accredited laboratory verification. |
| Mineral retention | = Full retention Selective adsorption targets contaminants. Calcium, magnesium, and potassium pass through at natural concentrations. | = Full retention (claimed) Berkey claims to retain beneficial minerals while removing contaminants. The gravity-fed carbon-based media is not designed to strip minerals. |
| Bathing water protection | ✓ Yes — all water in the home PFAS and chlorine are absorbed through skin and inhaled in steam. Whole-house filtration protects against dermal and inhalation exposure. | – None Countertop gravity filters treat drinking water only. Shower and bathing water — a significant route of chemical exposure — is not covered. |
| Construction material | ✓ 316L medical-grade stainless steel Higher-grade stainless steel used in medical devices and marine environments. Superior corrosion resistance. 10-year warranty. | – 304 stainless steel Standard food-grade stainless steel. Adequate for countertop use but lower corrosion resistance than 316L. |
| Portability / off-grid use | – Requires mains water pressure Designed for permanent installation on pressurised water supply lines. | ✓ Fully portable (gravity-fed) No water pressure or electricity needed. Popular for off-grid, emergency, and travel use. Can filter from any fresh water source. |
| Installation | – 1–2 hours (plumber, one-time) Professional inline installation at the main supply. No ongoing professional maintenance required. | ✓ No installation required Place on countertop, pour water in. Ready to use immediately. |
| Upfront cost | – €760–€3,598 Essential to Complete Set Plus. One-time purchase covering the entire household. | ✓ $280–$630 (unit only) Royal Berkey ~$400. Replacement Black Berkey filter pairs cost $120–$150 and last ~6,000 gallons. |
| Cost per litre (all water) | ✓ ~€0.002–0.004/L Calculated over 10 years across full household water usage. All water in the home is filtered. | – ~€0.01–0.02/L (drinking only) Per-litre cost for drinking water only. Does not include shower, bath, or appliance water which remains unfiltered. |
Common Questions
Is Berkey still safe to use after the EPA stop-sale?
Berkey resumed sales after addressing the EPA's concerns about unsubstantiated pesticide device claims. The stop-sale was related to marketing claims, not a product safety recall. However, the episode highlights a broader issue: Berkey's performance claims are largely based on internal testing rather than independent accredited laboratory verification. For households that prioritise independently certified contaminant removal, a system with ETH Zurich or equivalent third-party certification provides greater assurance.
Does Berkey remove PFAS?
Berkey claims high PFAS reduction rates based on internal testing data. However, no independent third-party laboratory certification (NSF, ETH Zurich, or equivalent ISO/IEC 17025 accredited facility) has been published confirming full-spectrum PFAS removal — particularly for short-chain PFAS compounds (PFBS, PFHxA, PFBA) which are increasingly prevalent in water supplies as legacy long-chain PFAS are phased out.
Why doesn't Berkey have NSF certification?
NSF certification requires manufacturers to submit products for independent testing at accredited laboratories, meet specific performance standards, and undergo regular facility audits. Berkey has historically chosen not to pursue NSF certification for most of its product line. The company has stated that it conducts its own testing, but this is not equivalent to independent third-party verification.
Which is better for a family home — Berkey or Mam Nature?
For a permanent home with mains water supply, Mam Nature Swiss provides superior protection: whole-house coverage (including bathing water), ETH Zurich certified PFAS removal, and a single annual cartridge change. Berkey is better suited for portable or off-grid use — camping, travel, emergency preparedness — where gravity-fed operation is essential.
Can Berkey protect shower and bathing water?
No. Berkey is a countertop gravity filter that treats only the water manually poured into it. It cannot be connected to shower, bath, or appliance lines. PFAS and chlorine are absorbed through the skin and inhaled in shower steam. Whole-house filtration is the only approach that addresses all exposure routes.
More comparisons
Whole-House Protection — Certified by ETH Zurich
The Mam Nature Complete Set filters every tap and shower in your home. 95–99.9% PFAS removal. 316L stainless steel. One cartridge per year.