WaterGrade supplier guides
Understand your water company
Explore local hardness, published quality results and what they mean for your home. Choose your supplier to find reports, compare available history and get practical help.
19 supplier guides
Parts of London, South East and eastern England
Affinity Water
Affinity’s quality page includes a postcode-based hardness and fluoride search. The company states that it does not add fluoride; that does not mean naturally occurring fluoride is absent.
92 named areas with records
Explore hardness, quality and help →Eastern England
Anglian Water
The supplier’s report tool includes hardness and a more detailed drinking-water report. That fuller report is useful when you need a specific substance, sampling context or an original document to compare.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Bristol and surrounding supply areas
Bristol Water
Bristol’s quality information separates local composition and hardness from its wider testing programme. Its guidance describes a postcode search for recent local sample results.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Cambridge and surrounding supply areas
Cambridge Water
Its quality hub separates local standards and reports from hardness, appearance, taste, lead-pipe and fluoridation information. Each topic answers a different question; hardness alone cannot describe the full quality of a supply.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Wales and adjoining English areas
Dŵr Cymru Welsh Water
Welsh Water explains that its zone reports summarise samples taken across a zone during a year. They are not tests at each individual property, even when found using a postcode.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Mid and north-east Wales
Hafren Dyfrdwy
Its quality checker offers the last 12 months, quarter or month, and reports hardness, water origins and mineral information. Choosing a different window changes what the result summarises.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Northern Ireland
Northern Ireland 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.
66 named areas with records
Explore hardness, quality and help →Portsmouth and surrounding supply areas
Portsmouth Water
The supplier provides area-specific hardness and quality results alongside advice on treatment and chlorine. Its own descriptive hardness bands may differ from WaterGrade’s scale, so compare the number and units.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Scotland
Scottish Water
Scottish Water publishes annual hardness tables separately from its zone quality reports. It calculates annual hardness from calcium and magnesium measurements. A newer quality report therefore need not contain a newer hardness figure.
369 named areas with records
Explore hardness, quality and help →Parts of Surrey, Kent and south London
SES Water
SES publishes postcode-based quality and hardness reports. Its hardness guidance explains that some sources are partially softened during treatment, while other sources are naturally softer; a general chalk-groundwater assumption is therefore insufficient.
Supplier guide · local data not yet imported
Explore hardness, quality and help →The Midlands and adjoining areas
Severn Trent Water
Its official checker offers several reporting windows. The typical hardness summary does not necessarily use the same sampling period as the detailed water-quality table.
218 named areas with records
Explore hardness, quality and help →South East England
South East Water
The supplier explains that much of its water comes from underground chalk aquifers, which contributes to hardness. This source description is context, not a numeric hardness result for every customer.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Staffordshire and the West Midlands
South Staffs Water
The supplier publishes zone-specific hardness in several units, with links to more detailed quality parameters and explanations of technical terms. Those figures and the monitoring period need to travel together.
Supplier guide · local data not yet imported
Explore hardness, quality and help →South West England
South West Water
The official quality search provides a supply-zone map, local hardness and the most recent report. A zone map describes reporting geography; it does not mean samples were collected at every address inside it.
Supplier guide · local data not yet imported
Explore hardness, quality and help →Southern England
Southern Water
Southern’s hard-water checker provides local hardness and a full quality report. Its separate incident service covers current reported problems and planned works; annual results cannot replace those updates.
Supplier guide · local data not yet imported
Explore hardness, quality and help →London and the Thames Valley
Thames Water
Its water-quality programme samples the network and customers’ taps. Local annual reports are more useful for understanding your supply than a headline company-wide compliance percentage.
245 named areas with records
Explore hardness, quality and help →North West England
United Utilities
The supplier’s water-supply page combines a postcode quality search with links to local network updates and reservoir information. A water-quality report and a current interruption notice answer different questions.
57 named areas with records
Explore hardness, quality and help →South West England
Wessex Water
Its postcode results show hardness in several appliance units and link to a fuller quality PDF. The PDF can contain qualified results and historical exceedance information that is not visible in the short website summary.
44 named areas with records
Explore hardness, quality and help →Yorkshire
Yorkshire Water
Yorkshire’s postcode tool links to water-supply-zone reports. Its guidance explains that water characteristics depend on the source and can vary through the year.
33 named areas with records
Explore hardness, quality and help →A local report is more useful than a company score
Supply zones can differ in hardness, mineral content and reporting period. We show original sources and local measurements where verified, rather than assigning a blanket water-quality rating.
How we check the dataWhere UK water quality and hardness data is publishedCan’t find your supplier?
Independent suppliers and new developments may use different networks. A private well or borehole also needs different information from a mains-water report.
DWI’s England and Wales supplier directory ↗