Published on: 24.1.2022

Information produced by Finnish Environment Institute

Soil frost affects water services

For Finnish water and wastewater services, soil frost is a hard nut to crack. Its impacts must be accounted for when building a well, water pipeline or sewer.

To prevent them from freezing in winter, water pipes and sewers must be placed in the ground below frost depth. Allowance must be made for exceptionally cold winters during which soil frost can reach deeper than usual. An additional problem is that frost depth varies from place to place. Soil frost penetrates deeper under yards and roads from which snow is cleared away than in areas covered with snow.

If a water pipe cannot be placed at a frost-free depth, it must be equipped with heating or insulated so well that it cannot freeze.

Soil frost can also cause other problems for pipelines besides the risk of freezing. Frost heaving can move water pipes or sewers, causing them to leak. A leak in a water pipe can lead to water contamination and, in the worst-case scenario, an outbreak of water-borne disease. A leaking sewer can put groundwater quality at risk.

Soil frost can also move well structures around, for example displacing the topmost rings of well. This may allow surface water to seep into the well through the joints of the rings. Sufficient frost protection is vital when building a well.

Image: © Jussi Leino