UK Water Utility AuthorityDWI Water Quality VerifiedUpdated: 27 June 2025

Severn Trent Water Water Hardness

Supplying 8 million customers across the heart of England from the Welsh border to the Humber. Discover network-wide PPM ratings, chalk aquifer vs reservoir water sources, and local appliance calibration guidelines.

Quick Search Verdict

Is Severn Trent Water Water Hard or Soft?

Moderately Hard

159.6 PPM

11.2° Clark

Severn Trent spans a dramatic hydrogeological divide: Birmingham and the Black Country receive naturally soft water (40–60 PPM) piped 73 miles from Wales, whereas Nottingham, Leicester, and Derby receive hard water (220–290 PPM) from lowland rivers and sandstone aquifers.

Primary Abstraction: Western supplies originate in impermeable gritstone and slate catchments of the Welsh Elan Valley. Eastern supplies rely heavily on the River Trent, River Derwent, and Sherwood sandstone boreholes rich in minerals.

Regional Limescale Risk

Moderate Risk-20% vs UK avg

Serving 292 postal districts across West Midlands, East Midlands, Gloucestershire & Mid-Wales.

Network Average

159.6 mg/L

11.2° Clark (16.0°fH / 8.9°dH)

Network Coverage

292 Outcodes

Mapped across 1130 local sectors

Softest Outcode

CH5

150 PPM (Slightly Hard)

Hardest Outcode

WV99

160 PPM (Slightly Hard)

Where Does Severn Trent Water Water Come From?

Water hardness across Severn Trent Water's licensed territory is strictly determined by regional hydrogeology. Rainwater is naturally soft when it falls from clouds, but absorbs dissolved minerals as it percolates through soil and rock layers before municipal abstraction.

Primary Catchment Profile: Blend of Welsh upland reservoirs (Elan Valley), lowland rivers (Severn & Derwent), and Sherwood sandstone boreholes.

Major population centers served by Severn Trent Water include: Birmingham, Coventry, Nottingham, Leicester, Derby, Stoke-on-Trent, Worcester. If your water bill comes from Severn Trent Water, your tap water is certified by the Drinking Water Inspectorate (DWI) and adheres to all British potable safety standards.

DWI Technical Reference

Supplier Codesevern-trent-water
Typical Range40 – 300 PPM (Varies dramatically by region)
Source Classificationmixed catchment
Coverage RegionWest Midlands, East Midlands, Gloucestershire & Mid-Wales

Appliance Care & Heating Compliance for Severn Trent Water Customers

Kettle Descaling Protocol

If in Birmingham, descaling is rarely needed. If in Nottingham, Leicester, or Derby, descale monthly with citric acid.

Dishwasher Salt Calibration

Birmingham: set to H00 or H01 (salt optional). East Midlands: set to H04 or H05 with mandatory salt top-ups.

Combi Boiler Protection (BS 7593)

East Midlands addresses require BS 7593 compliant inline scale protection. West Midlands homes should focus on corrosion inhibitors.

Expert Softener Recommendation: Not recommended for Birmingham or Wolverhampton (already soft). Highly beneficial in Nottingham and Leicester homes suffering from hard water deposits.

Severn Trent Water Network Postcode Outcodes (292)

Search and explore official DWI water hardness readings across all postal districts supplied by Severn Trent Water.

Severn Trent Water Water Hardness

Is Severn Trent Water Water Hard or Soft?

Where Does Severn Trent Water Water Come From?

DWI Technical Reference

Appliance Care & Heating Compliance for Severn Trent Water Customers

Severn Trent Water Network Postcode Outcodes (292)

Protect Your Heating & Appliances in WV99 (159.6 PPM): Compare Local Specialists

Frequently Asked Questions: Severn Trent Water Water Hardness

Is Severn Trent water hard or soft?

Why is tap water in Birmingham soft while Nottingham is hard?

Do I need dishwasher salt in Severn Trent areas?

Does Severn Trent water damage combi boilers?