Water conditions vary by supply zone
Dŵr Cymru Welsh Water explains that hardness depends on whether local water comes from upland reservoirs or groundwater sources. Use its “In Your Area” information for the full postcode rather than assuming every Cardiff property receives identical water.
Signs such as limescale, reduced soap lather or deposits can indicate harder water, but they do not identify the cause of a plumbing fault. Describe the symptoms and the affected fitting.
Check whether the issue is wider than your home
If water suddenly looks, smells or tastes different, or pressure has changed, ask a neighbour and check the water company’s incident information. If the issue is limited to your property or one outlet, internal plumbing is a more likely starting point.
Information for a clearer quote
Include the property type, room, number of affected outlets and when the problem began. Say whether the main stop tap works and whether you are the owner, tenant or landlord arranging the repair. For flats, mention the floor and any shared-service or managing-agent restrictions.
Sources and further information
External guidance can change. Follow the linked organisation where its advice applies to your situation.