Drinking water

Water is definitely one of the most precious natural resources. The availability of pure drinking water is of critical importance for people. We understand our responsibility in supplying good quality drinking water to the population and give our best to protect the surrounding natural environment.

Tap water IS a drinking water

The quality of drinking water supplied to our customers in the capital city has been keeping the quality level comparable to Western European countries for several years already. 2014 was not different from the earlier years in terms of quality. Water quality is characterized by its compliance with legal requirements. In 2014, we took 2 496 samples from the consumers’ taps in Tallinn and Saue. So far the best ever result of 99.80% of all the samples being compliant with all the requirements was achieved. Only 6 samples were not compliant with the quality requirements because of the higher iron content. We immediately performed the maintenance works on the water pipeline in the street, and as a result, the repeat samples met all the quality requirements. In the service area of Maardu, 100% of samples taken from the consumers’ taps were compliant with all the requirements.

Strict quality control

The quality of drinking water is subject to strict legal requirements and we have also agreed on additional quality standards in the levels of service within the Services Agreement concluded with the City of Tallinn. In terms of water quality, we have outperformed those requirements assuring good quality of drinking water to each customer.

Water quality is inspected by following the drinking water monitoring programme approved by the Health Board. The programme specifies the sampling points, sampling frequency and the parameters to be analysed. Samples are taken from raw water (Lake Ülemiste, catchment area thereof and ground water), treatment process and consumers’ taps. There are 120 sampling points in Tallinn including kindergartens, schools and other institutions that have been evenly spread out across the entire service area. 24 samples are taken from each sampling point per annum. That means that a total of approximately 3 000 water samples are taken from consumers’ taps. The production and supply of drinking water involves taking of nearly 30,000 samples and making approximately 80,000 analyses per annum.

The structure of the Company also includes a laboratory unit, which has been accredited by the Estonian Accreditation Centre since 2001. Laboratory unit consists of a water and microbiology laboratory at Ülemiste Water Treatment Plant and a wastewater laboratory at Paljassaare Wastewater Treatment Plant.

Water analyses are made in our water and microbiology laboratory, which is also one of the largest laboratories in Estonia. The attested samplers guarantee the quality of analyses, accredited quality management system (ISO 17025) and modern equipment as well as professional staff that enable offering a wide range of services also outside the Company. Water quality is independently monitored by the Northern Services of the Health Board and Supervisory Foundation of Water Companies in Tallinn, and the Estonian Accreditation Centre supervises our laboratories.

Water treatment

Ülemiste Water Treatment Plant treats water according to the treatment scheme widely used worldwide. We are using ozone to improve the quality, odour, colour and taste of water and this has enabled us to reduce the volume of chlorine used to almost a tenth over a decade. Drinking water must be safe and must not contain any infectious bacteria. For this purpose, we are adding small quantity of chlorine, which is absolutely safe for human health, but extremely effective for protecting water against bacteria during its journey through the network up to the consumers’ tap.

Surface water quality

Lake Ülemiste is the drinking water source for more than 400,000 people living in Tallinn and its nearest surroundings. Almost 90% of our consumers in Tallinn (City Centre, Lasnamäe, Mustamäe, Northern Tallinn, Kristiine, Haabersti), City of Maardu and Pirita settlement are supplied with drinking water produced out of surface water.

Although Lake Ülemiste serves as the main drinking water source for Tallinners, the natural catchment area of the lake itself is small. Therefore, an extensive water catchment system has been set up in order to provide sufficient supply. Surface water quality is mostly affected by the weather conditions. Thus, the entire water catchment system influences surface water quality. Our main challenges are related to the weather – first of all floodings and changes in raw water due to lengthy winter periods.

The quality of surface water sources is inspected according to the programme established by the permit for the special use of water. Our accredited laboratory analyses the quality of water sources in the entire catchment area, we also analyse the water in Lake Ülemiste, as well as the water taken to the lake. We use the results to assess changes and processes on the catchment area and decide upon the need to restock water in the lake.

Ground water quality

Approximately 10% of the population in Tallinn is supplied with drinking water extracted from the ground water available in the area. These areas supplied with ground water are Nõmme, Laagri, Merivälja, Pirita, Tiskre, City of Saue and Tiskre village in Harku Rural Municipality. All ground water quality parameters are monitored according to the requirements of the permits for a special use of water, drinking water source and drinking water monitoring programmes. If necessary, ground water is additionally treated.

Pressure filters installed in the ground water pumping stations for removing excess iron, ammonium and manganese enable to ensure good quality drinking water supply. Water tests show that treatment significantly improves also the organoleptic qualities of water, such as colour, odour and taste, and increases the oxygen content.

Security of supply and quality

It is essential for the residents to have a good quality service available 24/7. This is why we focus on the continuous improvement of the security of our supply and service.

Water quality at the consumers’ tap is not impacted solely by the age of the network. The water network must be properly maintained in a timely manner and repaired if it has been deemed necessary. We are constantly carrying out maintenance and renewal works on the networks in order to maintain and improve drinking water quality. We clean and flush the network regularly to ensure the supply of high quality drinking water to our consumers. This way sediments get removed from the inner surface of pipes, which is one of the most important methods of improving water quality in the distribution network. In 2014, we carried out air scouring on 145 km of the water network. Investments in replacing old water pipes and network extensions have facilitated improvement in water quality at the consumers’ tap and more efficient usage of water resources. In 2014, we reconstructed 5.6 km of the water network.

Year-on-year reduction in leakage level demonstrates a more sustainable usage of water resources. Figuratively speaking, constant reduction in leakage level means that nearly 13,000 m3 of treated drinking water is daily being saved up, when compared to the time ten years ago. 200,000 m3 of water was saved in 2014 compared to the year before. This is the amount of water that Tallinners consume in 3 days. In 2014, water loss in the distribution network was 16.14%, while in 2013 the same figure was 16.98%.