In May, We Told You to Check Your Town's Water. We Sent You to the Wrong Number.

In May, we told 948 of you that Spain's national nitrate alarm was useless and your own town's reading was the whole job. More of you clicked that issue than any other we sent this spring, which suggests a lot of people went and looked up their municipality.

We have spent this week marking our own homework, and this one produced the most uncomfortable result of the season. The advice was right in spirit and wrong in resolution. Your town's nitrate figure is also an average, hiding exactly the same way the national figure did, and the numbers we printed were two years old when we printed them.

Here is the corrected version, which is mostly good news.

The town readings came from Greenpeace's map, published in April. We described them as the most recent readings. They were built on consolidated 2024 data, and the current figures are dramatically better.

Algarrobo, which we put at 31 mg/L, reads 10 mg/L as of March 2026. Benamargosa, which we flagged at 42 mg/L and "close to the line," reads 3 mg/L as of December 2025, an improvement of 39 mg/L in a year, though it stays on the watch list because of that history. Alhaurín el Grande's municipal network, which we listed at 34, reads 4 mg/L.

Those figures come from SINAC, the health ministry's national drinking-water database, which every tool in this piece is ultimately reading from. Confirmed August 2026 against a July extraction.

We also put Marbella above the precautionary 6 mg/L line. Every Acosol network in Marbella reads between 0 and 1 mg/L, because the water is treated with reverse osmosis before it reaches you.

A line on what that 6 mg/L figure actually is, since we leaned on it in May without explaining it. The legal ceiling across the EU is 50 mg/L, and that is the only number anyone enforces. The lower figure was proposed in November 2025 by an international expert group commissioned by Denmark's environment ministry, working from a Danish study that assessed nitrate exposure across 2.7 million adults. It is precautionary; it is not binding anywhere, including Denmark, and the cancer evidence underneath it is suggestive rather than settled. Denmark's new government said in June it intends to lower its national limit toward what its own experts recommend, which Greenpeace has called an EU first. Nothing has changed in law yet, there or here.

Two smaller corrections. We said ion-exchange systems do not remove nitrate, which is wrong; ion exchange, reverse osmosis and distillation all remove it, while carbon filters and jug filters do not, and boiling concentrates it. And we called the SINAC lookup a 60-second check. It is a seven-step path that requires you to know which distribution network serves your address, and the nitrate figure appears only in the annual full analysis, so the newest number can be a year old.

Which brings us to the thing we missed entirely.

Nitrate readings do not belong to towns. They belong to a red de distribución — distribution network, and a single municipality can hold dozens of them with completely different water.

Marbella currently carries a critical flag in the national data. That flag comes from one 78-resident apartment block with its own supply, which earned the label on a sustained history above 30 mg/L and now reads 20. The other 38 networks in the town, serving essentially everybody, read at or near zero.

Alhaurín el Grande is now formally recorded as exceeding the 50 mg/L legal limit. That breach is a single private urbanisation network serving 187 people from a dug well, reading 59 mg/L and worsening. The town's municipal network, serving 11,598 people, reads 4 mg/L. Confirmed August 2026.

Every current legal breach in Málaga province sits on a small private network. Not one sits on a major municipal supply.

That changes the question completely. It is not where you live. It is who pipes your water. If you are on municipal supply in a western Costa town, you are almost certainly on Acosol or Hidralia, treated, and reading near zero. If you live in an urbanisation or apartment block whose comunidad — residents' association runs its own supply or well, your water is a separate system with its own lab results, and nobody averages it into a comforting municipal figure.

Which is an uncomfortable pattern for our readership specifically, because the urbanisation is where a great many of us live. The villa on the hill with its own borehole can be drinking worse water than the flat in town.

There is a genuine current story in the data that appeared in no headline, ours included.

The network serving Torre del Mar and Caleta de Vélez, in Vélez-Málaga, reads 39 mg/L as of November 2025 and has worsened by 30.5 mg/L in a year. It serves 22,914 people. That is the largest population in Málaga province sitting in the elevated band, it is a coastal town with a substantial foreign community, and it is still legally compliant, which is precisely why nothing triggered and nobody was told. Confirmed August 2026.

For context on the wider picture, the drought is over. Andalucía formally declared it finished in April, and provincial reservoirs sit at 84.9% against 53.6% this week last year. We considered writing that summer scarcity was pushing readings up, checked it, and found the opposite. Wet year, improving numbers.

This takes about 90 seconds, once, and then you can leave it alone until something changes.

Work out which network serves you. If your water bill comes from Acosol, Hidralia, Aqualia or your ayuntamiento — town hall, you are on municipal supply. If it arrives through your community fees, you are on a private network and your administrador de fincas — property manager can tell you its name.

Then look the number up. The cleanest public source is El agua de tu pueblo at infoagua.es, a project by the journalism outfit DATADISTA that republishes the government data network by network, with each measurement date shown. SINAC itself is the official record if you want the underlying lab bulletin, though it will ask you for your network by name before it tells you anything.

We are also retiring a recommendation. In May, we pointed you at aguacostadelsol.es, which is genuinely useful and genuinely current. It is also completely anonymous: no named operator, no contact page, no legal notice. It works today, and nobody is accountable if it stops. Handing you a bookmark we do not control and calling the job done was the weakest part of that issue, so we have written the guide we should have written in May: how to identify your network, how to read the result, and what to do if the number is high.

If it is high and you are on a private network, the lever is your comunidad, not the town hall. Ask the administrator for the latest analysis in writing and put treatment on the agenda for the next meeting. If you would rather solve it at your own tap, an under-sink reverse osmosis unit runs roughly €200 to €450 installed on the Costa, with €50 to €80 a year in replacement filters. A jug filter will not do it.

The question that unlocks the entire lookup, for your administrator or your town hall:

The second one matters because the routine analyses do not include nitrate. Only the full one does.