Where the lead actually is
Lead pipework for drinking water has been banned in new installations across Europe since the 1990s, and water utilities replaced the bulk of public lead service lines through the 2000s and 2010s as the regulatory limit tightened. The problem moved. It did not disappear.
Four plausible sources remain, all of them downstream of the public network:
- the private service line, between the street main and the meter, part of which belongs to the owner in many older configurations
- the risers of buildings put up before 1950, sometimes left untouched by refurbishments that only reached the flats themselves
- tin-lead solder on copper pipework, standard practice until the 1990s
- the brass alloys in taps, valves, flexible hoses and fittings, which can contain a few per cent of lead. This is the least visible source and the only one that can be brand new. The European framework for materials in contact with drinking water has been tightening since the 2020 directive, but the stock already installed does not update itself.
A 1970s flat with a budget kitchen tap fitted last year can therefore test higher than a properly refurbished 19th century building. The age of the building is a clue, not an answer.
What the limit says, and what it does not
The quality limit that applies at the consumer’s tap is 10 micrograms per litre. Directive (EU) 2020/2184 lowers it to 5 micrograms per litre from January 2036, a long horizon that gives utilities time to deal with the service lines still in the ground.
These figures deserve to be read for what they are. Health authorities have not identified an exposure level below which no effect is expected, particularly in children and during pregnancy, which is why the tolerable weekly intake published previously was withdrawn rather than revised. A regulatory limit is a management compromise, not a certificate of safety. Put plainly: a result of 8 micrograms per litre is compliant, and that is not a reason to stop there.
pH, corrosivity, and the Flint mechanism
Lead does not enter the water because it is present. It enters because the chemistry of the water dissolves it. Three parameters govern this: pH, alkalinity, and the presence of a corrosion inhibitor, usually an orthophosphate. Inside an old pipe, a mineral scale has built up over years on the lead surface, and that scale is what protects the water. While it holds, the water stays clean.
What happened in Flint, Michigan, in 2014 and 2015 illustrates the mechanism better than any diagram. The city switched water source without maintaining corrosion control treatment. The new, more aggressive water gradually stripped the protective scale from lead service lines, and concentrations at the tap climbed for months before the problem was acknowledged.
The lesson travels. Soft, low-alkalinity water, of the kind distributed in granitic areas, is naturally more aggressive, which remineralisation treatment corrects. But any change disturbs the equilibrium: a new source, a network interconnection, and at the scale of a single home, a water softener set too low or a system left unused for weeks. Stagnation in particular is the single factor that weighs most on a morning sample.
Why you test at the tap, not at the mains
Regulatory monitoring results are public, area by area, and they are reliable. They describe the water produced and distributed. They do not describe what leaves your kitchen tap, because that depends on the last fifteen metres, for which nobody but you is responsible.
Two samples are enough to settle the question, and it is the gap between them that informs.
| Sample | Protocol | What it reveals |
|---|---|---|
| First draw | First litre after 4 to 8 hours without use, typically on waking | The worst case, and above all the contribution of the tap and its fittings |
| After flushing | After 2 minutes of running cold water | The water in the riser and the service line |
If the first draw is loaded and the flushed sample is clean, the source is local, usually the tap itself, and the fix costs about a hundred euros. If both are loaded, the riser and the service line are in question, and the matter becomes a collective one.
Use an accredited laboratory working by ICP-MS. Expect 40 to 90 euros per sample, bottle supplied, results in one to two weeks. Test strips and colorimetric kits sold online do not discriminate reliably in the range that matters, between 3 and 15 micrograms per litre. We do not use them and we advise against basing a decision on one.
What removes what
| Method | Dissolved lead | Worth knowing |
|---|---|---|
| Carbon block certified for lead reduction | Effective while the cartridge is within its rated life | Slow flow, replace by date rather than by taste |
| Granular carbon, entry-level jug filter | Little or none | Designed for taste and chlorine |
| Reverse osmosis under the sink | Highly effective, above 95 per cent | Reject water, remineralisation advisable, annual servicing, 300 to 900 euros |
| Dedicated ion exchange resin | Effective on metal cations | Not to be confused with a domestic softener |
| Salt-based water softener | No expected effect | Alters the calcium carbonate balance, and so corrosivity |
| Boiling | Makes it worse | Evaporation concentrates the metal |
The most common confusion concerns softeners. They treat hardness, not metals, and depending on how they are set they can make the water more aggressive towards the pipework they feed.
What to do, in order
Before any result arrives, two habits cost nothing: run the cold tap for thirty seconds to two minutes after a night or an absence, and never use hot tap water for drinking, cooking or making up infant formula, since it dissolves more and sometimes comes from a cylinder that was never intended for consumption.
After that, in order of yield: replace taps, hoses and fittings that are not certified for drinking water, put the condition of the risers on the agenda of the building’s owners’ meeting, and ask the utility to check the public portion of the service line, which remains theirs to replace where lead is still in place. While waiting for results, bottled water for infants and during pregnancy is a reasonable precaution.
One point without ambiguity: Lif8 measures buildings and provides no healthcare. A person’s lead exposure is established through a blood lead test ordered and interpreted by a doctor. A water analysis documents a dwelling, not a body.
