Sizing depends on hardness and daily water use. Oversizing wastes capacity; undersizing can trigger frequent regeneration.
Start with the simple checks
Check the water's hardness information, clean affected fixtures gently and follow the instructions for any filter or treatment equipment. Small maintenance habits often prevent bigger problems.
When to investigate further
If the issue affects several appliances or the water's taste, colour or odour changes suddenly, contact your water supplier or a qualified professional. Product labels and manufacturer guidance matter.
For related background, read what hard water means and compare practical water-treatment tools.