Drinking water in Lima and other regions contains faecal coliforms and heavy metals, according to an analysis by Digesa.
A study by the weekly Hildebrandt en sus trece (H13) showed that water in 16 districts of Peru’s capital Lima lacked sufficient chlorine. Sedapal denied responsibility. An investigation by the General Directorate of Environmental Health and Food Safety (Digesa) in 2022 found that the water reaching homes in 27 districts of Lima and 23 regions of the country contained faecal coliform bacteria, low levels of chlorine and heavy metals.
According to H13, the study was conducted between 2021 and 2022. Samples were taken from more than 17,000 population centres and 5,000 health facilities. This is the first report to be carried out on this scale,’ Pedro Cornetero García, coordinator of Digesa’s monitoring area for water for human consumption, told the newspaper.
What happened in Lima?
The study shows that the water in 16 districts of the capital did not have enough chlorine. The districts affected include San Martín de Porres, Puente Piedra, Los Olivos, Independencia, Rímac, Carabayllo, La Victoria, Comas and Ancón.
In Lurín and Pachacamac, on the other hand, faecal coliform bacteria, high levels of sodium and even free-living organisms were found.
Esther Lezcano, a biologist and researcher in water treatment projects, told the media that water containing faecal coliforms and helminth eggs indicates the presence of pathogens that “cause intestinal diseases, which are particularly dangerous for children, the elderly, the malnourished, the immunocompromised and cancer patients”.
The case of other regions
In the 23 regions analysed, faecal coliforms were also found, as well as heterotrophic bacteria, which allow the growth of other microorganisms that can be dangerous. In the case of Cusco, Loreto, Cajamarca and Ayacucho, helminth eggs were found. According to H13, this indicates that the water has been exposed to faecal contamination over a long period of time.
“If the situation is like this in Lima, it is much worse in the regions because the supplies are not well managed and the operators chlorinate the water poorly”, says engineer Francisco Arteaga, from the Institute of Hydraulics, Hydrology and Sanitary Engineering at the University of Piura.
Heavy metals
In Apurímac, Huancavelica, Puno, Moquegua, Madre de Dios and Tacna, heavy metals such as arsenic, mercury, aluminium, nickel and lead have been found. The former is considered carcinogenic by the World Health Organisation (WHO).
“Boiled water only guarantees the biological quality of the water, i.e. the elimination of all living organisms such as bacteria, viruses and parasites, but when it comes to heavy metals and chemical substances, boiling is useless. And in the long run it can cause health problems”, says Esther Lezcano.
The weekly also reports that in jungle regions such as Ucayali, Loreto and San Martin, below-standard levels of chlorine and biological and chemical contaminants have been detected. In San Martin, larvae and parasitic helminths were found. Aluminium was found in Loreto.
The problem of water pollution goes through several stages. It starts at the source of the water, then in the water treatment plants and finally in the old pipes. At none of the three levels has there been any significant change in recent years that would lead us to believe that the situation has changed since the study was carried out. “In addition, the regulation that sets the parameters for the substances allowed in drinking water is very permissive”, says Maynor López, a specialist in the production of ultrapure water.
When questioned by the media, the National Sanitation Service (Sunass) said that between 2023 and 2024 it had imposed 295 corrective measures on 32 service providers. This was due to a lack of cleaning of reservoirs and poor treatment of drinking water.
Of the 89 sanctions imposed in just 12 months, Sedapal (Lima) is in first place, followed by EPS Grau (Piura), EPS Chavín (Ancash) and Emapa de Cañete.
Pedro Cometero, the Digerin official, said that the budget they have is ‘the minimum’. “We need better and more laboratories. We lack personnel. If you ask the National Water Authority, they don’t have laboratories, OEFA doesn’t have laboratories”, he said.
Sedapal’s disclaimer
Sedapal issued a statement on 18 April 2025 in response to the H13 report on water quality in Lima and Callao. In it, the company assures that the water it distributes is safe for human consumption, as the water resource undergoes strict treatment, disinfection and quality control processes. In addition, residual chlorine levels are kept above the required minimum of 0.5 mg/l, according to constant monitoring from the treatment plants to the household connection: “We guarantee that residual chlorine levels are kept above the required minimum (0.5 mg/l),” it says.
The state-owned company states that it was neither informed nor involved in the sampling process of the DIGESA 2022 report, which was only sent to regional and local governments. It also points out that the report lacks basic technical data, such as the exact address, date, time and exact sampling point, and that many samples were allegedly taken in private homes, where the internal sanitary installations are the sole responsibility of the users. ‘The maintenance of the internal sanitary installations … corresponds exclusively to the users”, it says.
“To date, no anomaly has been detected that affects the quality of the water”, the agency said, highlighting its rigorous monitoring and quality control protocols, which include field sampling, physico-chemical and microbiological analysis, and on-line monitoring at strategic points in the distribution network. To date, no anomaly has been detected that would affect the quality of the water in Lima and Callao.
Finally, Sedapal “reaffirms its commitment to the health and well-being of the population, guaranteeing a safe and reliable drinking water service in accordance with the parameters established by law”.
