Falmouth Water Hardness & Quality Report (2026)
Water Hardness
9.4°Clark13.4°fH7.5°dH
Source
mixed
pH Level
7.6
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
308.8 mg/L
Est. Daily Cost
£0.30
energy & soap waste
Source: DWI Data Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Falmouth, your appliances are currently losing 18% efficiency due to mineral buildup.
| Appliance | In Falmouth | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.2 yrs | 8.5 yrs | -39% |
| Washing Machine | 8.7 yrs | 12 yrs | -28% |
| Water Heater | 10.3 yrs | 15 yrs | -31% |
Regional Water Comparison
How Falmouth compares to its nearest neighbours
| City | Hardness | Clark° | Risk | Source |
|---|---|---|---|---|
| ▶ Falmouth, South West | 133.5 mg/L | 9.4° | 🟠 Hard | mixed |
| Truro, South West | 198.5 mg/L | 13.9° | 🔴 Very Hard | mixed |
| Redruth, South West | 141 mg/L | 9.9° | 🟠 Hard | mixed |
| Helston, South West | 134 mg/L | 9.4° | 🟠 Hard | mixed |
| Camborne, South West | 224.5 mg/L | 15.7° | 🔴 Very Hard | mixed |
National Benchmark
How Falmouth compares to the United Kingdom average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Falmouth | 133.5 mg/L | 🟠 Moderate |
| United Kingdom National Avg | 183 mg/L | 🔴 High |
| Livingston Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Falmouth's Water Unique?
Local geology and source profile
Falmouth, the harbour town on the Fal estuary in south-west Cornwall, is served by South West Water, which draws supply from the Restormel (Clay Works) and Argal Reservoir network inland of Penryn and Truro. The Fal catchment and adjacent Carnon valley reservoir catchments drain the Cornish uplands, an area dominated by Devonian metasediments — slates, phyllites and schists that overlie the deeply buried Cornubian Granite Batholith. Treatment is carried out at Penhallow Water Treatment Works before distribution throughout the Fal peninsula. Although Cornwall is predominantly a soft-water county due to its hard, calcium-poor granite and slate geology, the Falmouth supply picks up moderate calcium from Devonian carbonate horizons present within the broader catchment.
The Devonian slates and phyllites of west Cornwall have negligible limestone content, but thin beds of Devonian limestone and calcareous mudstone occur within the local Devonian sequence, particularly in the Mylor Slate formation near the Fal estuary. Water draining these horizons, even in small proportion, contributes calcium and bicarbonate ions to the river supply. The result is a moderately soft hardness of 133.5 mg/L — harder than the granitic far west of Cornwall but considerably softer than chalk-dominated southern England. The TDS of 308.8 mg/L confirms a predominantly silicate catchment with limited dissolved minerals.
At 133.5 mg/L Falmouth's water is moderately soft, a significant advantage for household appliances. Kettles accumulate light limescale and should be descaled every six to eight weeks to keep heating elements efficient. Shower heads and tap aerators will show only light spotting and require cleaning every couple of months. Washing-up liquid lathers well. Combi-boilers and washing machines face relatively modest scaling risk, though fitting an inline scale inhibitor remains good practice. Falmouth residents enjoy markedly lower appliance maintenance costs compared with chalk-belt towns in south-east England.
Geology & Source: Supplied by South West Water from the River Fal catchment and Cornish upland reservoirs — dominated by Devonian slate and schist with limited Devonian limestone influence — produces moderately soft water at 133.5 mg/L (9.4°Clark).