A lettuce leaf gets tested for a few hours of its life. The water it drank for weeks is never tested at all.
Sewage outfalls, failed drainage, black-water rivers, fields irrigated with wastewater — we have been collecting where they are, worldwide, for years. Send us your growing locations and we will tell you which of them sit next to one.
That water is how contamination reaches a crop in the first place — and unlike the leaf, water can be watched from the outside, in advance.
So we watch it. For years we have been building a map of where water carries human sewage: discharges and failed drainage, black-water rivers, fecal coliforms in supply, and fields irrigated with untreated wastewater. Public reporting, geolocated, worldwide, and updated continuously. The same map covers industrial and mining water for other hazards; this page is about the sewage layer, because that is the one cyclospora travels in.
On its own that is a map of dirty water. It becomes useful when it is laid over the places your food actually comes from.
You know where your farms are. We know where the water is bad.
Why water and not the product. Take cyclospora. It cannot be caught at the loading dock, for a biological reason. An infected person sheds oocysts that are not yet infectious; the cell inside each capsule has to divide and mature — one to two weeks in warm, moist conditions outside a host — before it can make anyone ill.6 That interval is why the parasite does not pass from person to person, why it is seasonal, and why it arrives on produce rather than out of a kitchen. It needs somewhere warm and wet to ripen. Irrigation water provides it.7
Recovering that parasite from a leaf is slow, unreliable work, and by the time a laboratory has an answer the lettuce has been eaten.5 The hazard was visible upstream, in the condition of the water, long before it was detectable in anything you could put in a lab.
Two ways to use the map
Both look for the same thing: reported human sewage in water, which is the only way this parasite reaches a leaf. One checks it against your locations. The other describes a country you buy from.
Farm proximity mapping
You send the locations. We check each one against every sewage report we hold nearby, and send back a list in order of how close the water is.
- Which of your locations sit near reported sewage contamination
- What kind of report it is — discharge, drainage failure, black-water river, wastewater irrigation
- How close, and what was reported when
- Which lanes to prioritise for audit, water testing or second sourcing
What we need from you: your farms, growers or sites, with locations. A spreadsheet will do.
Country water report
No locations needed. We report where the sewage is in a country you buy from, so you can see the ground before you commit to a region or a grower.
- Where the sewage-contaminated water is, by region and by type
- Which growing areas overlap with it
- What has been reported recently, and how the pattern is moving
- Source records for every entry, so your team can verify it
What we need from you: the country, and what you buy there.
The water report is the part you cannot assemble yourself.
Every source behind this page is public. What takes years is geolocating sewage reporting worldwide, keeping it current, and holding it in a form that can be laid over a list of farms. Send the locations and we will do the overlay.
See it on your own locationsWhat a country report looks like
In summer 2026 thousands of people fell ill with cyclospora across dozens of US states. One lettuce sample gave a presumptive positive, which FDA laboratory experts re-reviewed and concluded did not represent true amplification; there has never been a confirmed positive product sample.24 The recall rests on epidemiology and a traceback to a supplier in central Mexico.12 The origin is still unconfirmed — which is the point: nobody found this parasite in food. So here is the same country run through our water data. Selected fecal-water contamination reports from the 52 indexed across Mexico over this period.8 The produce-growing states of central Mexico carried the pattern — and the home state of the supplier FDA's traceback converged on sits right in the middle of it.
The water went bad before people got sick
Reports of sewage-contaminated water in central Mexico's growing regions, set against the outbreak's own dates. This only means something if the epidemiological read is right. That is the assumption, and we state it before the result.
Signal phase — upstream, in the waterSource reports for these nine signals
- 2025-11-05Naucalpan, State of Mexico — sanitation and the Hondo River. The Water Diplomat.
waterdiplomat.org/story/2025/11/sanitation-and-hondo-river-naucalpan-mexico-reconciling-environmental-and-economic - 2025-11-12Santa Cruz Chignahuapan, State of Mexico — community under a river of black waters. Animal Político.
animalpolitico.com/estados/santa-cruz-chignahuapan-olvidada-aguas-negras-estado-mexico - 2025-11-30Mexico City — deep-drainage conflict points to be maintained. El Universal.
eluniversal.com.mx/metropoli/desazolvan-drenaje-profundo-gobierno-de-la-cdmx-dara-mantenimiento-a-puntos-conflictivos - 2026-01-13San Luis Potosí — black waters generating a focus of infection. Quadratín San Luis Potosí.
sanluispotosi.quadratin.com.mx/metropoli/aguas-negras-generan-foco-de-infeccion-en-colonia-julian-carrillo - 2026-03-13Guadalajara, Jalisco — fecal coliforms in drinking-water samples. Notisistema.
notisistema.com/noticias/siapa-detecta-coliformes-fecales-en-muestras-de-agua-potable-en-la-zmg - 2026-03-18Guanajuato — black-water river on the road to Cajones. Periódico Correo.
periodicocorreo.com.mx/guanajuato/2026/mar/18/guanajuato-rio-de-aguas-negras-en-camino-a-cajones-152691.html - 2026-03-23Tepetitlán, Hidalgo — sanitation of the Tula and Amajac rivers. El Universal Hidalgo.
eluniversalhidalgo.com.mx/municipios/impulsan-saneamiento-de-rios-tula-y-amajac-ante-altos-niveles-de-contaminacion - 2026-03-31Puebla — state human-rights commission demands Atoyac River sanitation. Milenio.
milenio.com/estados/cdh-puebla-demanda-acciones-saneamiento-rio-atoyac - 2026-04-27San Miguel Viejo, Guanajuato — black water used for irrigation. Periódico Correo.
periodicocorreo.com.mx/san-miguel/2026/apr/26/denuncian-uso-de-aguas-negras-para-riego-en-san-miguel-viejo-155497.html
What this example does and does not show. We did not find the farm, and we did not predict the recall. Nobody can name a grower from public sources and the origin is still unconfirmed. What the record shows is narrower: reports of sewage-contaminated water in that region, during the months the crop was growing, before anyone fell ill.8 If the investigation lands elsewhere, that changes the answer, and we will say so.
It also shows the limit of the method honestly. Proximity is not contamination. A sewage discharge ten kilometres from a field does not mean that field's water was dirty. What proximity gives you is an ordered list — which of your locations deserve a closer look, and which do not. That is a screening layer, not a verdict, and it is the thing that was missing here. The information was public and in advance — the same thing that was true of formaldehyde on Chinese cabbage a month later. Nobody had put it next to a map of farms.
Dirty water upstream. Recall downstream.
Is your farm near sewage-contaminated water?
Send your locations and we will check them. Or name a country and we will show you where the sewage is. Either way, you find out what you have been buying next to.
Map my farms Request a country reportIrrigation water screening FAQ
Why screen the water instead of testing the product?
Because of how the parasite behaves. An infected person sheds oocysts that are not yet infectious; the cell inside has to divide and mature for one to two weeks in warm, moist conditions outside a host before it can make anyone ill. Recovering it from a leaf is slow and unreliable, and by the time a laboratory has an answer the lettuce has been eaten. The water can be watched from the outside, in advance.
Does proximity to sewage mean a farm is contaminated?
No, and the method does not claim it. A sewage discharge ten kilometres from a field does not mean that field's water was dirty. What proximity gives you is an ordered list - which of your locations deserve a closer look, and which do not. It is a screening layer, not a verdict.
What did the Central Mexico example actually establish?
That reports of sewage-contaminated water existed in that region during the months the crop was growing, before anyone fell ill. It did not find the farm and it did not predict the recall. The origin of the 2026 outbreak is still unconfirmed, there has never been a confirmed positive product sample, and the recall rests on epidemiology and traceback.
Where these claims come from
- CDC — Investigation Update: Cyclospora Outbreak, July 2026.
cdc.gov - FDA — Investigation of 9-State Outbreak of Cyclospora Illnesses: Iceberg Lettuce (July 2026).
fda.gov - Supplier statement — company newsroom, regarding the cyclospora outbreak (July 2026).
company newsroom - CNBC — What the FDA lettuce false positive means (20 July 2026).
cnbc.com - Forbes — Where the cyclosporiasis outbreak stands after the false positive (M. Roeloffs, 20 July 2026).
forbes.com - CDC — Clinical Overview of Cyclosporiasis (2026).
cdc.gov - Johns Hopkins Bloomberg School of Public Health — Understanding the Cyclosporiasis Outbreak (2026).
publichealth.jhu.edu - iComplai platform — sewage-contamination signal data.
Outbreak facts are cited inline and listed in full under references. Signal data: iComplai platform — sewage-contamination monitoring, Mexico, Nov 2025 – Jul 2026.