Northern Ireland

Northern Ireland Water: water quality and hardness

Northern Ireland Water provides public drinking-water and wastewater services. Its official postcode results include local water-quality information, hardness and dishwasher settings.

An independent WaterGrade guide. Local readings vary by source area and date.

Find the water serving your home

Our match uses NI Water’s published annual postcode file; confirm your current supply if arrangements have changed.

How Northern Ireland Water reports on your water

NI Water also publishes annual hardness and postcode-to-zone files through open data. Those files describe their reporting year; the relationship between an address and a zone should not be assumed unchanged forever.

Our postcode lookup uses the supplier’s published annual mapping. Ambiguous matches stay ambiguous. Confirm your current supply with NI Water when arrangements have changed, and use its service-updates page for present-day notices.

Company information and source context ↗

What WaterGrade currently holds

Named areas with records: 66
Areas with measured hardness: 66
Areas with other quality data: 66
Areas with annual hardness history: 62

These count our verified records, including historical areas. They are not the company’s current total zones, population coverage or a quality score.

Approved hardness editions cover 2023–2025. These are hardness publications, not a complete extraction of all NI Water quality parameters.

Is the water hard or soft?

Check the figure for your supply zone. A company can deliver water from different sources, so a single average can give the wrong appliance setting for your home. Hardness describes dissolved minerals; it is not a safety rating.

Our local cards use mg/l as calcium carbonate (CaCO₃). Keep the original unit and reporting period when comparing results. Supplier labels can use different hardness bands.

Convert appliance units Set up your dishwasher Filters and limescale

What do the quality results tell you?

Read each parameter with its units, sample count, range and reporting period. A mean below a reference limit does not establish that every sample complied. A “less than” result is not an exact concentration.

Company-wide performance, local zone results and water at an individual tap are different levels of information. Historical exceedances need the supplier’s investigation context; they are not automatically a current incident.

Understand the measurements in a water report

One named-area example · not a company average

Inside the Altnahinch Bushmills report

87.54 mg/l as CaCO₃ · hardness period: 2025

Quality reporting period: 2025. 4 parameters in this publication. Hardness may come from a separate source and period.

This selected example may not serve your postcode. Open the full report for ranges, source notes, any reported contraventions and the original document.

Read the full Altnahinch Bushmills report →

Find your local source-area report

Use the exact area name from the supplier’s checker. Older areas can have been renamed or replaced. Each card keeps the hardness period separate from other quality data.

Search by the exact source-area nameWith annual hardness history

66 areas match · showing 24.

Altnahinch Bushmills

87.54 mg/l as CaCO₃ · Soft

Hardness period: 2025

Quality report: 2025 · 1 other parameters