What it is
pH is measured on a scale from 0 to 14, with 7 neutral. Below 7 is acidic, above 7 alkaline. Drinking water is normally close to neutral, and the guideline is a range rather than a single figure.
Where it comes from
pH is set mainly by the rocks and soil the water has passed through. Water from granite or peaty upland catchments is often soft and acidic; water from chalk and limestone is hard and alkaline. Rainwater is naturally slightly acidic.
Why it matters
pH itself has no direct health effect within the range found in drinking water. It matters because acidic water corrodes pipes and fittings, releasing metals such as lead, copper and iron into the water, and because pH affects how well disinfection and other treatment work. Very alkaline water can taste bitter and cause scale.
What can be done about it
Low pH is corrected with a neutralising filter, which passes the water through a bed of calcium-based media, or by dosing a small amount of alkali. High pH is less common and is usually addressed as part of wider treatment. A Pozzani engineer will size the unit to the supply and check for any metals already picked up from the pipework.
Information last reviewed 5 October 2026 by Pozzani Pure Water.