Chatham Water Hardness & Quality Report (2026)
Water Hardness
20.2°Clark28.8°fH16.1°dH
Source
mixed
pH Level
8.3
neutral = 7.0
Lead
0.004 mg/L
✓ Below action level
TDS
755 mg/L
Est. Daily Cost
£0.65
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 Chatham, your appliances are currently losing 38% efficiency due to mineral buildup.
| Appliance | In Chatham | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.5 yrs | 8.5 yrs | -82% |
| Washing Machine | 3 yrs | 12 yrs | -75% |
| Water Heater | 5 yrs | 15 yrs | -67% |
Regional Water Comparison
How Chatham compares to its nearest neighbours
| City | Hardness | Clark° | Risk | Source |
|---|---|---|---|---|
| ▶ Chatham, South East | 287.5 mg/L | 20.2° | 🔴 Very Hard | mixed |
| Gillingham, South East | 316 mg/L | 22.2° | 🔴 Very Hard | mixed |
| Rochester, South East | 224 mg/L | 15.7° | 🔴 Very Hard | mixed |
| Strood, South East | 219.5 mg/L | 15.4° | 🔴 Very Hard | mixed |
| Snodland, South East | 272.5 mg/L | 19.1° | 🔴 Very Hard | mixed |
National Benchmark
How Chatham compares to the United Kingdom average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Chatham | 287.5 mg/L | 🔴 High |
| United Kingdom National Avg | 183 mg/L | 🔴 High |
| Livingston Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Chatham's Water Unique?
Local geology and source profile
Chatham, the former naval dockyard town in the Medway unitary authority in Kent, is supplied by South East Water from the North Downs Chalk Aquifer of the Medway valley. South East Water's chalk abstraction sites in the Medway valley — including Eccles, Burham, and Snodland borehole fields — access the thick Cretaceous Upper Chalk underlying the Medway valley floor and the flanking North Downs escarpment. The River Medway drains chalk and Wealden catchments, delivering additional chalk-derived mineral content to the valley. Chatham shares the same supply infrastructure as its neighbouring Medway towns — Gillingham (316 mg/L) and Rochester — and the high chalk-derived hardness is characteristic of the entire Medway conurbation. Water is treated at South East Water's Kent facilities before distribution to Chatham and the Historic Dockyard area.
Chatham's very hard water — 287.5 mg/L (20.2°Clark) — results from the deep North Downs Chalk Aquifer of the Medway valley, where prolonged chalk-groundwater contact produces very high calcium concentrations. The North Downs chalk ridge flanking the Medway is a thick Cretaceous Upper Chalk sequence whose valley exposures at the Medway crossing are some of the most productive chalk horizons in Kent. The chalk here has undergone deep groundwater circulation, producing very high dissolved calcium concentrations at depth. The Drinking Water Inspectorate (DWI) classifies Chatham's supply as very hard.
Limescale is a serious daily challenge in Chatham. At 287.5 mg/L, limescale forms rapidly in kettles — a white crust within one to two weeks requiring fortnightly descaling. Combi-boiler heat exchangers face serious risk from rapid limescale accumulation; annual boiler servicing with limescale inspection is essential, and fitting a polyphosphate scale inhibitor is strongly recommended. Showerheads, taps, and shower screens develop heavy deposits requiring regular aggressive treatment. Washing-up liquid lathers very poorly. Chatham homeowners and landlords should prioritise limescale management, considering a full water softener for comprehensive protection.
Geology & Source: Supplied by South East Water from the North Downs Chalk Aquifer in the Medway valley — Chatham, one of the Medway towns, draws on the same deep chalk borehole network as Gillingham and Maidstone, producing very hard water at 287.5 mg/L (20.2°Clark).