Procedures for securing the quality of household water

Municipal health protection authorities must prepare for possible incident situations in which health hazards are transmitted by household water. Preparation is carried out in cooperation with water supply plants and other authorities.

Incident situations that jeopardise the quality of household water, i.e. the water in supply networks, can be due to 

  • operations that jeopardise the water quality at the catchment areas of raw water 
  • the water abstraction plant’s vulnerable location
  • a water abstraction or process equipment malfunction
  • faults in the water supply network
  • accidents
  • natural phenomena such as rainstorms or floods
  • human factors
  • vandalism 
  • availability issues such as interruptions in electricity supply or telecommunications.

Procedures for securing the quality of household water guidelines at the end of this page describe practical measures to take in various incident situations that jeopardise the quality of household water. The guidelines specify what to do if household water is contaminated. Operators and authorities must know what to do if household water is contaminated with pathogenic microbes, hazardous substances, radioactive substances, or blue-green algae or the toxins they produce. 

The guidelines describe the cooperation and responsibilities of the authorities, operators and third sector (Finnish Red Cross, Voluntary Rescue Service Vapepa) in investigating the situation. The guidelines include hyperlinks to other instructions and manuals found online. The guidelines’ appendices give further information about intestinal parasite contamination and household waterborne microbes that have caused epidemics. 

The appendix to the communication guideline includes examples of an emergency warning and an instruction to boil water, and notice templates by the City of Hämeenlinna for microbiological contamination in 15 languages. Valvira prepares and updates the guidelines as required. The guidelines are Valvira’s plan to secure the quality of household water in accidents and other special situations in accordance with the Health Protection Act.