Water supply and sanitation in Indonesia is characterized by poor levels of access and service quality. More than 16 million people lack access to an at least basic water source and almost 33 million of the country's 275 million population has no access to at least basic sanitation. Only about 2% of people have access to sewerage in urban areas; this is one of the lowest in the world among middle-income countries. Water pollution is widespread on Bali and Java. Women in Jakarta report spending US$11 per month on boiling water, implying a significant burden for the poor.

The estimated level of public investment of only US$2 per capita a year in 2005 was insufficient to expand services significantly and to properly maintain assets. Furthermore, policy responsibilities are fragmented between different Ministries. Since decentralization was introduced in Indonesia in 2001 local governments (districts) have gained responsibility for water supply and sanitation. However, this has so far not translated into an improvement of access or service quality, mainly because devolution of responsibilities has not been followed by adequate fund channeling mechanisms to carry out this responsibility. Local utilities remain weak.

The provision of clean drinking water has unfortunately not yet been taken up as a development priority, particularly at the provincial government level.UNICEF:UNICEF Indonesia-Overview-Water & Environmental Sanitation. Retrieved February 12, 2012. The lack of access to clean water and sanitation remains a serious challenge, especially in slums and rural areas. This is a major concern because lack of clean water reduces the level of hygiene in the communities and it also raises the probability of people contracting skin diseases or other waterborne diseases. A failure to aggressively promote behaviour change, particularly among low-income families and slum dwellers, has further worsened the health impact of Indonesia's water and sanitation situation.

Water resources and use

Indonesia has over 5,590 rivers, most of them short and steep. Because of high rainfall intensities most rivers carry large quantities of sediment. Average rainfall is above on most islands, except for the Lesser Sunda Islands where it is .FAO Aquastat:Indonesia, version 1999, retrieved on October 17, 2010 80% of rain falls during the rainy season (October to April). While water resources are quite abundant in Sumatra, Kalimantan, Sulawesi, Maluku and Irian, water shortages occur during the dry season in parts of Java, Bali and the Lesser Sunda Islands. In particular in Java, the dry season flows are inadequate to meet the demand, leading to irrigation shortages. Irrigation accounts for 93% of water use. The total storage capacity amounts to only 5–6% of the river flows. Construction of reservoirs is constrained by lack of good reservoir sites, high density of population at possible reservoir sites and expected short reservoir lifetimes due to siltation. Groundwater potential in Indonesia is very limited. However, much of the eastern islands depend on groundwater because of surface water scarcity. Groundwater overexploitation occurs in heavily populated coastal areas of Java, including in Jakarta and Semarang. In Jakarta, it has caused seawater intrusion up to from the coast and land subsidence at a rate of 2–34 cm/year in east Jakarta. In Semarang, land subsidence occurs at a rate of 9 cm/year.

Water utilities abstract water from rivers and lakes (60%), springs (25%) and groundwater (15%). For example, the main water source for Jakarta is the Jatiluhur Dam on the Citarum River southeast of the city. For those who are self-supplied or receive water from community-based organizations, shallow groundwater and springs are by far the main sources of water on most islands. On Sumatra and Irian, however, rainwater harvesting is also an important water source.Hendrayanto, Bogor Agricultural University:Watershed and Water Resources Management in Indonesia: AnOverview of Forest Degradation and Present Situation of Water Resources Supply and Efficient Utilization for Human Survival and Bioproduction, 2004, p. 7-8, quoting BPS-Statistic Indonesia figures for 2002, retrieved on October 17, 2010

Pollution Domestic sewage, industrial effluents, agricultural runoff, and mismanaged solid waste are polluting surface and groundwater, especially in Java. Indonesia ranks among the worst countries in Asia in sewerage and sanitation coverage. Few Indonesian cities possess even minimal sanitation systems. The absence of an established sanitation network forces many households to rely upon private septic tanks or to dispose of their waste directly into rivers and canals. The commonality of the latter practice, together with the prevalence of polluted shallow wells used for drinking water supply in urban areas, has led to repeated epidemics of gastrointestinal infections.World Bank:Indonesia Environment Monitor 2003, Special focus: Reducing pollution, p. 20-32, retrieved on October 17, 2010

Domestic waste According to Water Environment Partnership in Asia (WEPA), only 42.8% from 51,372,661 houses in Indonesia have domestic waste treatment. More than half of households dispose their domestic waste directly to the river body.WEPA:State of Water Environmental Issues in Indonesia. Retrieved on February 24, 2012 Data from the World Bank shows that in 2008, only 52% of Indonesian population has an adequate access to excreta disposal facilities. Such facilities are important as they can help to minimize human, animal, and insect contact with excreta, thereby increasing the hygiene level and enhancing the living conditions for the slum-dwellers. Without proper construction and maintenance of these facilities, domestic wastes are disposed ineffectively and increases the rate of water resources degradation.The World Bank:Improved sanitation facilities (% of population with access). Retrieved on February 24, 2012

Industrial waste Industrial activities wastes such as small-scale industries, agriculture, textile, pulp and paper, petrochemical, mining and oil and gas also contribute to the degradation of water quality in Indonesia. Water quality in locations near to the mining areas is potentially contaminated by heavy metal such as mercury (Hg). According to WEPA, some level of mercury (Hg) concentration has been detected at 9 out of 16 sampling points and the highest level of dissolved mercury in one of the area reach 2.78 ug/L.

Therefore, the result of water quality monitoring in 30 rivers in Indonesia indicates that most of river water qualities do not end up meeting water criteria class 1, i.e. water that can be used for standard water, drinking water, and or other usage that requires the same water quality with such usage, due to pollution by domestic and industrial wastes (drinking water raw based on Government Regulation Number 82, 2001, Water Quality Management and Wastewater Controlling).MOHA-SEMAC:GOVERNMENT REGULATION OF THE REPUBLIC OF INDONESIA NUMBER: 82 OF 2001 REGARDING WATER QUALITY MANAGEMENT AND WATER POLLUTION CONTROL. p.4-5. Retrieved on February 24, 2012

Access IndicatorsService levels Urban Rural Total Improved water source Basic services 97.6% 85.7% 92.4% Piped water 44.6% 21.4% 34.6% Improved sanitation Basic services 91.6% 79.7% 86.5%Sewerage (2010)Joint Monitoring Programme for Water Supply and Sanitation of WHO and UNICEF:Indonesia data 2010 . Retrieved April 21, 2013. 2% 0% 1% Data on access to water and sanitation in Indonesia varies depending on the source consulted and the definition of access. In 2020, access to an improved water source stood at 92% and access to improved sanitation at 86% in 2020. Indonesia has one of the lowest sewerage coverage levels in Asia with only 2% access in urban areas. Most excreta and wastewater are discharged untreated or semi-treated into local drains or water bodies, causing massive environmental pollution. Dense housing, severe seasonal flooding and the choking of drains with uncollected solid waste exacerbate the problem. According to the World Bank, urban sanitation is the least well addressed of major policy issues in Indonesia.World Bank:PROJECT APPRAISAL DOCUMENT ON A PROPOSED CREDIT TO THE REPUBLIC OF INDONESIA FOR A THIRD WATER SUPPLY AND SANITATION FOR LOW INCOME COMMUNITIES (PAMSJMAS) PROJECT, June 1, 2006, Annex 1. Retrieved March 7, 2010. In rural areas, access to improved sanitation has increased from 23% in 2000 to 80% in 2020. In 2020, 6.1% use shared latrines, 1.4% use unsanitary open pits, and 6.1% defecate in fields, beaches and water bodies.

Service quality No data is available on the average continuity of water supply in Indonesian cities. However, in Jakarta, 92% of users received continuous water supply in 2001.Asian Development Bank:City Profile:Jakarta Water Supply, Data as of 2001. Retrieved March 7, 2010. Concerning drinking water quality, about 30% of the water distributed by water companies in the country is contaminated with E. coli or fecal coliforms and other pathogens.According to Ismail Malik of the Ministry of Health, quoted in Asian Development Bank:Country Water Action: Indonesia Simple Solution for Drinking Water Makes Big Difference , March 2006. Retrieved March 7, 2010. The results of drinking water quality tests are not made public. Most Indonesians do not dare to drink water directly from the tap and boil water or buy bottled water, if they can afford it.Wijanti Hadipuro:Indonesia's Water Supply Regulatory Framework:Between Commercialisation and Public Service? , Water Alternatives 3(3), p. 482, retrieved on October 15, 2010

Health impact of inadequate water supply and sanitation Unsafe drinking water is a major cause of diarrhea, which is the second leading killer of children under five in the country and accounts for about 20% of child deaths each year. Every year, at least 300 out of 1,000 Indonesians suffer from water-borne diseases, including cholera, dysentery, and typhoid fever, according to the Ministry of Health.Asian Development Bank:Country Water Action: Indonesia Simple Solution for Drinking Water Makes Big Difference , March 2006. Retrieved March 7, 2010. World Bank's Water and Sanitation Program (WSP) in 2008 revealed that poor sanitation, including poor hygiene causes at least 120 million disease episodes and also 50,000 premature deaths annually.East Asia: Economics of Sanitation Initiative. Retrieved on 11 February 2012. Significant damage to the country's future potential in terms of infant mortality and child malnutrition in low-income areas of Indonesia is greatly associated with inadequate access to safe water and basic sanitation.

Economic impact of inadequate water supply and sanitation The economic costs associated with inadequate water supply and unsanitary conditions represent formidable obstacles to the improvement of living standard. The enormous economic costs resulting from chronic ill health can contribute to poor nutrition, poor school performance, reduced productivity, and permanent disability and thus represent a drag on economic development.