Water Quality
Lead in drinking water: what laboratory testing tells us
Lead usually enters water within a building's own plumbing, which is why sampling protocol shapes the result.
19 November 2025 · 6 min read
The source is usually local
Where lead is found in tap water, it typically originates in the property's pipework, solder or fittings rather than in the source water. That is why a supplier's area report cannot answer the question for a specific tap.
Standing time changes the number
Water that has been standing in pipework has had longer to interact with plumbing materials. First-draw and flushed samples can therefore differ substantially, and both can be useful.
Reading the result
Lead is reported in µg/L with a detection limit and the sampling protocol used. Interpreting it alongside pH, hardness and other metals gives a clearer picture of what is happening in the plumbing.
Common questions
- Does clear water mean there is no lead?
- No. Dissolved metals such as lead are not visible, which is why laboratory analysis is used rather than appearance.