The issue with this type of water is that its quality depends on your living region. Suppose tap water contains too many salts, the pH of the soil changes in the direction of alkalization. This disturbs the plants’ absorption of phosphorus, iron, manganese, boron, and other important elements. The high content of calcium and magnesium salts in the water leads to the fact that these elements are converted into compounds unavailable for plants, and the assimilation of iron, which is necessary for photosynthesis, is blocked.
Indoor plants might get chlorosis - the leaves turn lighter, then turn yellow and die off. The soil may exude an unpleasant putrid or acidic odor, indicating that the roots are rotting. In this case, be sure to transplant the cannabis into different soil, removing the rotted roots.
Watering with hard water also results in a white crust on the soil’s surface and white stains on the walls of ceramic pots.