Temporary change in part of Pitkäkoski water treatment plant's water production between May and October, continues until January 2022

We will streamline the water treatment process at the Pitkäkoski water treatment plant and increase production capacity during 2020-2025. We made similar improvements at the Vanhakaupunki water treatment plant in 2015-2016. With these measures, we will improve the operational reliability of water services. Due to the renovation work, we will make temporary changes to the Pitkäkoski water treatment plant's production process between 10 May and 31 October 2021. Update 7.12.2021: The temporary changes continue until January 2022.

The production changes concern the activated carbon filtration plant that is not in operation during this period. The other treatment process works more efficiently during the outage. The concentration of organic carbon in the supply water produced during the bypassing of the activated carbon filtration plant rises from the normal level of 1.9 mg/l to about 2.4 mg/l. In addition, slight changes in turbidity and iron content may occur. These changes will not have a significant impact on supply water quality.

Due to the higher content of organic matter, the chlorine content of supply water leaving the water treatment plant will be increased from the current level of 0.4 mg/l to 0.6 mg/l. This may be noticed as a slight odour and taste of chlorine in tap water.

The quality of the water produced meets the quality requirements and targets in accordance with the Decree on Domestic Water (1352/2015) also during the changes. During the process change, we monitor water quality more frequently than usual and publish the results of our analyses every two weeks on our website. The first results will be published in week 20.

The change concerns the following areas:

• Espoo
• Helsinki: Southern major district, Central major district, Western major district, Northern major district
• Kauniainen 
• Vantaa. 

We monitor the microbiological, physicochemical and organoleptic quality of the water leaving the HSY water treatment plants and the mains water in our operational laboratory. We perform approximately 40,000 water analyses annually.