County Durham · North East

Is Darlington water hard or soft?

Slightly Hard at 97 ppm · 17 postcode districts

  • Supplier Northumbrian Water
  • County County Durham
  • Postcodes 17
Area average
97
ppm CaCO₃
Slightly Hard
Soft
Moderate
Hard
Very hard
0100200300400+

Darlington water hardness at a glance

  1. Darlington water is slightly hard, averaging 97 ppm across 17 postcode districts.
  2. That is 110 ppm below the UK average of 207 ppm.
  3. The hardest district is DL17 at 122 ppm; the softest is DL1 at 74 ppm.
  4. The supplier is Northumbrian Water.
  5. Limescale builds slowly at this level, so a softener is not usually needed.

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The average water hardness in Darlington is 97 ppm, classified as slightly hard. Darlington is served by Northumbrian Water, covering 17 postcode districts across County Durham in the North East region.

Hardness varies across the area. See the table below for a breakdown by postcode district. DL17 has the hardest water at 122 ppm, while DL1 is the softest at 74 ppm.

By postcode

Water Hardness by Postcode in Darlington

Sorted by hardness. Tap a postcode for full details.

Postcode Water Company Hardness PPM Level
DL17 Northumbrian Water
122
122 ppm Moderately Hard
DL16 Northumbrian Water
121
121 ppm Moderately Hard
DL15 Northumbrian Water
120
120 ppm Slightly Hard
DL14 Northumbrian Water
119
119 ppm Slightly Hard
DL13 Northumbrian Water
118
118 ppm Slightly Hard
DL12 Northumbrian Water
117
117 ppm Slightly Hard
DL11 Northumbrian Water
116
116 ppm Slightly Hard
DL10 Northumbrian Water
115
115 ppm Slightly Hard
DL9 Northumbrian Water
82
82 ppm Slightly Hard
DL8 Northumbrian Water
81
81 ppm Slightly Hard
DL7 Northumbrian Water
80
80 ppm Slightly Hard
DL6 Northumbrian Water
79
79 ppm Slightly Hard
DL5 Northumbrian Water
78
78 ppm Slightly Hard
DL4 Northumbrian Water
77
77 ppm Slightly Hard
DL3 Northumbrian Water
76
76 ppm Slightly Hard
DL2 Northumbrian Water
75
75 ppm Slightly Hard
DL1 Northumbrian Water
74
74 ppm Slightly Hard
Suppliers

Water Companies Serving Darlington

Tap for full coverage area and hardness data.

Northumbrian Water

101 ppm Slightly Hard

Each water company publishes its own hardness data, so you can cross-check the Darlington figures here against the published hardness data from Northumbrian Water.

Water Hardness Guides

Learn more about water hardness and how to manage it.

What Is Water Hardness? Effects Solutions Water Softeners Limescale Removal

Test Your Water in Darlington

At 97 ppm, your water is slightly hard. A home testing kit lets you verify the exact hardness and check for other contaminants.

TESPERT 16-in-1 Water Testing Kit

Home water test strips that check hardness, pH, chlorine, lead, and 12 other parameters. Results in around 60 seconds. 125 strips per pack.

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FAQ

Common questions about Darlington water

Is Darlington water hard or soft?
Darlington is classified as slightly hard, averaging 97 ppm across 17 postcode districts. Limescale build-up is minimal at this level, though individual postcodes vary.
Which postcode in Darlington has the hardest water?
DL17 has the hardest water in Darlington at 122 ppm, while DL1 is the softest at 74 ppm. See the full table above for every district.
Which water company supplies Darlington?
Darlington is supplied by Northumbrian Water, covering 17 postcode districts across County Durham.
Is tap water in Darlington safe to drink?
Hardness is not a safety issue: the World Health Organization sets no health-based limit for water hardness, so hard and soft water are both fine to drink. Drinking water quality is regulated by the Drinking Water Inspectorate in England and Wales and the Drinking Water Quality Regulator in Scotland, and your water company publishes test results for your area.
Does Darlington have any harder-water postcodes?
DL17 is the hardest district at 122 ppm (moderately hard), though most of Darlington averages 97 ppm.
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