Programme description

Title: Using pressure management to reduce water loss
Commissioned by: German Federal Ministry for Economic Cooperation and Development (BMZ)
Country: Peru
Partner: SEDAPAL (state water supply company of the Peruvian capital Lima), VAG-Armaturen GmbH
Overall term: 2008 to 2010

Context

Peruvian water supply companies have to deal with high volumes of water loss. The combination of unregistered connections and water meters that are defective or have been tampered with on the one hand, and leaks and burst pipes in the urban water supply systems on the other result in a large discrepancy between the volume of water fed into the system and the amount of drinking water charged to the end consumer. For SEDAPAL Lima, by far the largest water supplier in Peru, the losses amount to almost 40 % of the drinking water it supplies. The national average is far greater.

These water losses place a burden on the water companies’ finances, since water lost must be compensated for by supplying additional drinking water, the treatment of which is expensive. The costs are covered in part by tariff increases or by public funding. As a result there are no funds available for improving or extending existing networks.

The amount of water escaping via leakages is related not only to the size of the holes but also to a large extent on the water pressure. Water pipes are designed on the basis of maximum demand. However, if less water is consumed, during the night for example, the pressure in the supply pipes rises. As a result, the volume of water escaping also increases, as well as the risk of burst pipes.

At SEDAPAL’s request, GIZ initiated a development partnership with VAG-Armaturen GmbH (VAG) in 2008. This medium-sized enterprise with its headquarters in Mannheim operates internationally and is a leader in water and wastewater technology.

Objective

Pressure management in the supply networks of two pilot sectors is more efficient and access to information about advanced water supply technology is guaranteed.

Approach

Under the development partnership, the water supplier SEDAPAL, supported by GIZ and VAG, has introduced water supply pressure management systems in two of its sectors. The technology from VAG consists of modern pressure regulating valves, which adjust the water pressure according to demand via a central control system. Employees from the water company have been trained in using the new technology and the knowledge has been consolidated in the National Water and Sanitation Capacity-building System established by GIZ. Through this and existing SEDAPAL networks the knowledge and results will be made available nationally.

Results achieved so far

By introducing new technology, water losses in SEDAPAL’s supply sector 86 (Lima) have been reduced by 11 % on a long-term basis. Thus 1,329 square metres  of water is saved daily, which corresponds to the average use of around 11,100 people. For the project partner SEDAPAL this has led to an annual cost saving of roughly EUR 97,000.

Based on these positive outcomes the Peruvian Ministry responsible in this area has initiated a national programme of water loss reduction (Programa de Gestión de la Demanda de Agua). In future this will make resources available to the water companies for repairing and maintaining the supply systems.

In the long term, effective pressure management can reduce wear and tear on supply lines and prevent burst pipes, in turn improving the efficiency, effectiveness and quality of the water supply.