Fluoride in UK tap water: understanding your local result

Natural fluoride and fluoridation are different questions

DWI explains that fluoride occurs naturally in water sources. Some water supplies are also fluoridated. Ask the supplier about the specific supply scheme if you want to know the origin; do not infer it from a company name or a single concentration.

Check the units and period

Reports may use mg/l or µg/l. There are 1,000 micrograms in one milligram: 225 µg/l is 0.225 mg/l. Compare the same unit and reporting period, retain less-than symbols, and use the supply-area report rather than a national map for local detail.

What a reference limit can tell you

DWI states a fluoride standard of 1.5 mg/l for the supplies it regulates. Keep the source’s units, sample counts and investigation notes when interpreting compliance. An annual area average does not answer every household or health question; ask the supplier about water results and a qualified health professional about personal clinical advice.

Related questions

• Water quality testing: who to contact and what to ask
• Hard water vs soft water: what the difference means