UK Legal Limit
0.01 mg/L
WHO Guideline
0.01 mg/L
EU Standard
0.01 mg/L
Primary Sources
Geology, mining legacy
Arsenic in UK drinking water is regulated at 0.01 mg/L. The WHO guideline is 0.01 mg/L and the EU standard is 0.01 mg/L. Arsenic occurs naturally in groundwater in parts of Cornwall and Devon. It is classified as a Group 1 carcinogen with no safe level of long-term exposure.
Arsenic is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Chronic exposure through drinking water is linked to cancers of the skin, bladder, lungs, and kidneys. Long-term ingestion at levels above the regulatory limit can also cause skin lesions, cardiovascular disease, diabetes, and neurological effects. Children and pregnant women are particularly vulnerable.
In the UK, the primary source of arsenic in drinking water is natural dissolution from underground rock formations, especially in the south-west of England where mineralised geology is common. Legacy mining operations in Cornwall and Devon have also contributed to elevated arsenic levels in some groundwater sources. Industrial activities, wood preservation using chromated copper arsenate, and agricultural pesticide residues are additional but less common sources.
| Jurisdiction | Limit / Guideline | Notes |
|---|---|---|
| UK (DWI) | 0.01 mg/L | Regulated under the Water Supply (Water Quality) Regulations 2016 |
| WHO | 0.01 mg/L | World Health Organization Guidelines for Drinking-water Quality |
| EU | 0.01 mg/L | EU Drinking Water Directive (2020/2184). The UK no longer automatically mirrors EU standards post-Brexit. |
Reverse osmosis
A membrane filtration process that removes up to 99% of contaminants by forcing water through a semi-permeable membrane under pressure. Highly effective but produces some wastewater.
Ion exchange
Replaces unwanted ions (such as nitrate or lead) with harmless ones using resin beads. Effective and widely used in both whole-house and point-of-use systems.
Activated carbon
Porous carbon material (from charcoal or coconut shell) that adsorbs contaminants as water passes through. Best for organic compounds and some heavy metals.
These list arsenic among what they reduce. Check your own report first — a filter is only worth buying for a contaminant your supply actually has.
Listed to reduce Arsenic
Waterdrop G3P600 Reverse Osmosis
Reverse Osmosis · NSF/ANSI 58, NSF/ANSI 372
Typical price
£550approx.
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Listed to reduce Arsenic
ZeroWater 12-Cup Ready-Pour
Jug Filter · NSF/ANSI 53, NSF/ANSI 401
Typical price
£40approx.
Affiliate link: we may earn a commission at no extra cost to you.
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