Test data
What our filters remove, and how we know.
Every figure on this site comes from a lab report, a manufacturer specification sheet or the manufacturer's instructions. Here they all are, by cartridge.
How to read it
Tested is not the same as certified.
An independent body such as NSF has evaluated a specific product or system and lists it. We only say “certified” where the manufacturer lists that certification for the product.
A lab followed the test method of a standard (for example NSF/ANSI 53 for PFAS). It shows performance, but it is not a certification.
Figures from Doulton's specification sheets, performance tables and in-house lab. We name the document next to each figure.
By cartridge
British Berkefeld Ultra Sterasyl
The standard cartridge for British Berkefeld gravity filters. Keeps fluoride. Rated for 1,500 L or 6 months.
Microplastics
Tested to NSF/ANSI 401. Doulton specification sheet.
PFOA + PFOS, to 3,000 L
QFT lab, report 22-131, 2022, NSF/ANSI 53 PFAS protocol.
Lead, on average
Doulton filter performance table, 2022.
Chlorine
Doulton specification sheet.
Bacteria and cysts
Doulton specification sheet and performance table, 2022.
19 of 22 pharmaceuticals, to 3,030 L
Lab report 21-155, 2021.
By cartridge
British Berkefeld Ultra Fluoride
For fluoridated town supply when you want to reduce fluoride. Rated for 1,500 L or 6 months. NSF certification is listed as pending by the manufacturer, so we do not claim it.
Fluoride, on average
Doulton product data for Ultra Fluoride, doulton.com. We make no other claims for this cartridge.
By cartridge
Doulton Biotect Ultra and Biotect Ultra SI
The cartridge in Doulton benchtop and underbench systems. Rated for 2,300 L or 6 months. Doulton does not market Biotect Ultra for fluoride.
Microplastics
Tested to NSF/ANSI 401. Doulton specification sheet.
Lead
Doulton specification sheet.
Chlorine
Doulton specification sheet.
Bacteria and cysts
Doulton specification sheet.
Cadmium / mercury, on average
Doulton specification sheet.
Certifications and approvals
What is certified, and for what.
Ultra Sterasyl in the British Berkefeld 8.5L system; Doulton EcoFast system
As listed in the manufacturer's instructions. Standard 42 covers taste and odour; Standard 53 covers health-related contaminants. Claims beyond the listed contaminants are not evaluated by NSF.
Ultra Sterasyl; British Berkefeld 1L
Lead-free materials, as listed in the manufacturer's instructions.
Filter elements and housings
Approved as safe in contact with drinking water in the UK. It does not measure filtration.
Ultra Fluoride
The manufacturer lists NSF certification for Ultra Fluoride as pending. We will update this page if that changes.
What we do not claim
The limits, stated plainly.
- We make no claims about viruses. The data we hold covers bacteria and cysts.
- We make no claims about nitrate. None of the cartridges we sell is tested for it.
- Biotect Ultra is not a fluoride filter. For fluoride, use Ultra Fluoride or the 9B04 pre-filter.
- The shower filter is in-house tested by the manufacturer for chlorine and sediment only.
- Results apply within each cartridge's rated life. Change cartridges on time.
The reports
Want to read the reports?
Ask us for a copy of any report named on this page: QFT 22-131, report 21-155, or the Doulton specification sheets and performance table.