Slightly Hard at 97 ppm · 17 postcode districts
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.
Sorted by hardness — tap a postcode for full details.
Tap for full coverage area and hardness data.
Learn more about water hardness and how to manage it.
At 97 ppm, your water is slightly hard. A home testing kit lets you verify the exact hardness and check for other contaminants.
Quick home water test strips — checks hardness, pH, chlorine, lead, and 12 other parameters. Results in 60 seconds. 100 strips per pack.
View on AmazonBe notified when water companies in Darlington report changes to hardness levels.