Peru’s water supply issues are due not so much to the availability of water resources but rather to the highly heterogeneous and conflicting geographical distribution of water resources and the population and economic activities [10], [11]. Access to water and sanitation services issues are, on the other hand, due to the insufficient financial and technical resources commanded by local governments [12].

With an average annual rainfall of 2,347 mm, Peru receives enough water to not suffer water scarcity problems. The total amount of renewable (surface and groundwater) water potentially available every year is 2,484,078 Mm3; with a population of 31,237,385 people (as of 2017), this would allow some 79,523 m3 of water to be available per person per year on average, the 12th largest availability rate in the world.

This water is unevenly distributed across the country. The country’s territory has been subdivided into three major watersheds (hydrographic regions, strictly): the Amazonian watershed comprises 74.5% of the country’s area, receives some 2,400 mm of rain per year, and gets 98.2% of all the renewable water available in the country; the Pacific watershed comprises 21.7% of the territory, receives almost no rain, and holds only 1.6% of the water available; and the Titicaca watershed, which comprises 3.8% of the country’s area, receives 700 mm of rain every year, and contains 0.3% of the renewable water available.

Total water consumption in Peru is estimated at 37,259.04 hm3/yr, as of 2018 [13], [14]. Most (86%) of this water is used in agriculture and livestock ranching, followed by manufacture and services (7%), human consumption (5%), and mining (1.6%). Water utilized for non-consumptive uses is estimated at 61,028.7 hm3, most of which (98%) is used for electricity generation. 

However, the country’s population and economic activities have been historically concentrated in the Costa region [13]: about 65% of the country’s population, 73.8% of the irrigated agricultural land, and most industrial activities. Thus, 74.4%, 72.1%, and 88.4% of all the water used countrywide for agriculture, human consumption, and industry and services, respectively, is used up in the Pacific watershed. Per capita water availability in this watershed is only 1,926 m3 per year on average and, in some parts, is even lower than 1,000 m3/person/yr, indicating chronic water stress conditions. For example, water availability in the Rimac river watershed, where Lima city is located, is only 125 m3/ person/yr, indicating absolute water scarcity. In contrast, 31.6% of the country’s population reside in the Amazon watershed, where each person has as much as 246,846 m3 of water available every year. Only 3.5% of the population reside in the Titicaca watershed, each person having 6,209 m3 of water available per year.  

Population and economic development both heavily concentrated in the Costa region have created a large demand for water, posing enormous pressure on the Pacific watershed’s water resources. Over 71% of the watershed’s entire supply of renewable water is consumed every year, making the region highly vulnerable to climate variability and droughts. In fact, a water deficit emergency was declared in all the departments of the Pacific watershed in 2016 [15]. The still growing population of Peru, with high and increasing urbanization, and plans to further develop its industrial and agro-industrial sectors, will put significant additional pressure. Climate change is expected to reduce the availability and increase the variability of water resources, thus further straining the supply of water.

Access to water and sanitation services in major urban areas has improved considerably over the last years, but significant deficits remain in small cities and rural areas [16]. In major urban areas these services are provided by dedicated, not-for-profit public utilities (Empresas Proveedoras de Servicios, EPS), the operation of which is regularly overseen by a national supervisory authority (the Superintendencia Nacional de Servicios de Saneamiento, SUNASS). As a result, the coverage and quality of water supply and wastewater collection and treatment services in urban zones have been steadily improving  [5], [6], [7], [8]. A total of 50 EPS were operating across the country in 2020; these supplied drinking water to 89.9% (some 18.76 million people or 72.7% of the country’s urban population) and drainage services to 83.8% (some 17.49 million people or 67.8% of the country’s urban population) of the people in their jurisdictions and treated 77.5% of the wastewater collected through drainage networks. However, eight EPS had no wastewater treatment plant and discharged the wastewater collected directly into rivers, lakes, or the coastal sea, with no prior treatment.

Water and sanitation services in small cities (those with 2,001–15,000 inhabitants) and rural areas are, in contrast, provided by the local government (municipalities) — either directly or through third-party entities — or are not available at all. Some 25,000 entities providing water and sanitations services in small cities and rural areas had been identified in 2019, many of which with limited technical and material capacities and providing suboptimal services [12].

Although locally differentiated fees are to be paid by the users of water and sanitation services, these are regarded as contributions rather than as charges for the services. Those reduced fees do not cover the actual cost of the services and yet many users are unable to pay them. Thus, the operation, maintenance, and improvement of water and sanitation utilities relies on transfers from, and investments made by, the central government. This is the main cause of regional gaps in access to water and sanitation services: 71% of the investments made in this sector have targeted urban zones.