Regional data · Legionella Index

The Legionella Index: London

Every dataset on the Index, filtered to London: confirmed Legionnaires' disease figures where UKHSA publishes them, tracked enforcement cases, water hardness for 17 towns, and what the councils here ask of landlords.

Part of the Legionella Data Index · compiled 2 August 2026

n/pConfirmed cases, not published
1Enforcement cases tracked
n/aTotal fines in tracked cases
17Towns in the hardness dataset
01 / SURVEILLANCE

Legionnaires' disease in London

UKHSA does not state a confirmed case count for London in the surveillance text. Full region-by-region counts for every English region are not published; the figures that are published are on the national Index. Surveillance counts only laboratory-confirmed, reported cases, so any published figure is a floor, not the true total.

02 / ENFORCEMENT

Prosecutions tracked in London

The tracker holds 1 legionella prosecutions from London, totalling £0 in fines (2016–2016).

DefendantYearSectorFineProsecutor
St Christopher's Hospice Death/outbreak
The Sydenham hospice failed to appoint a competent person to control legionella in its hot and cold water system. A patient died of Legionnaires' disease in August 2012 and an orderly later spent 18 days in a coma. Convicted at Southwark Crown Court in 2016 of breaching HSWA ss.2 and 3; sentenced to a two-year conditional discharge and ordered to pay £25,000 in costs. No fine was imposed. Recorded as a prosecution with a death rather than a fine. Source
2016 Healthcare n/a HSE

The full UK record, its curation rules and the per-sector breakdown are on the Legionella Enforcement Tracker; sector views sit under the Index.

03 / WATER HARDNESS

Water hardness in London towns

12 of 17 towns here carry a reported hardness figure; the rest show a band inferred from the water company's own statement, or an honest gap. Every row names its source and confidence. Scale risk uses the DWI/WHO anchor: scaling begins around 200 mg/l CaCO₃.

TownWater companyHardness (mg/l CaCO₃)Hardness bandScale riskEvidence
BarkingThames Water342Very hardVery highSingle source - unverified (WaterGrade)
BarnetAffinity Water270HardHighSingle source - unverified (WaterGrade)
BromleyThames Water282HardHighSingle source - unverified (WaterGrade)
CroydonThames WaterHard to very hard (>200 mg/l typical) *High to very high *Company statement - band only (Thames Water)
Thames Water Access Code 2025 states most supplies in its region are hard (>200 mg/l as CaCO3).
EalingThames Water263HardHighSingle source - unverified (WaterGrade)
EnfieldThames WaterHard to very hard (>200 mg/l typical) *High to very high *Company statement - band only (Thames Water)
Thames Water Access Code 2025 states most supplies in its region are hard (>200 mg/l as CaCO3).
HarrowAffinity Water363Very hardVery highSingle source - unverified (WaterGrade)
HounslowThames Water263HardHighSingle source - unverified (WaterGrade)
IlfordThames WaterHard to very hard (>200 mg/l typical) *High to very high *Company statement - band only (Thames Water)
Thames Water Access Code 2025 states most supplies in its region are hard (>200 mg/l as CaCO3).
Kingston upon ThamesThames WaterHard to very hard (>200 mg/l typical) *High to very high *Company statement - band only (Thames Water)
Thames Water Access Code 2025 states most supplies in its region are hard (>200 mg/l as CaCO3).
LondonThames Water260-320Hard to Very hardHigh to very highTwo agreeing sources - unverified (MyTapWater + WaterGrade)
Two independent aggregators agree; still to be spot-checked against the company checker.
Richmond upon ThamesThames Water251HardHighSingle source - unverified (WaterGrade)
RomfordThames WaterHard to very hard (>200 mg/l typical) *High to very high *Company statement - band only (Thames Water)
Thames Water Access Code 2025 states most supplies in its region are hard (>200 mg/l as CaCO3).
SuttonSES Water265.8HardHighSingle source - unverified (WaterGrade)
TwickenhamThames Water251HardHighSingle source - unverified (WaterGrade)
UxbridgeAffinity Water308Very hardVery highSingle source - unverified (WaterGrade)
WembleyAffinity Water295HardHighSingle source - unverified (WaterGrade)

* Band or scale risk inferred from the water company's own published statement, not a measured town value. Figures labelled "unverified" come from aggregator sites and should be confirmed against the company's postcode water-quality checker before being relied on. How this dataset is built.

04 / COUNCIL DUTIES

What councils in London ask of landlords

The national legionella duty is the same everywhere; what varies locally is property licensing and whether legionella is written into licence conditions. These verified councils fall in London:

CouncilNationSchemeIn forceLegionella in licensing?
Westminster City Council
15 wards
Council's Standards for Rental Accommodation: "Landlords must carry out a Legionella risk assessment for all rented properties… hot water stored at 60°C or above, cold below 20°C…" Source document
EnglandSelective licensing24 Nov 2025 onwardsGuidance / standards only
London Borough of Newham
Selective: 22 wards (excl. Royal Victoria and Stratford Olympic Park), £750. Additional: borough-wide, in force 1 January 2023
EnglandSelective licensing + Additional HMO licensing1 Jun 2023 onwardsNot yet verified
London Borough of Tower Hamlets
Additional: borough-wide. Selective: Whitechapel, Weavers, Spitalfields & Banglatown areas (HMOs there moved to additional licensing from 1 April 2024)
EnglandAdditional HMO licensing + Selective licensing1 Apr 2024 onwardsNot yet verified
London Borough of Waltham Forest
Near-borough-wide
EnglandSelective licensing1 May 2025 – 30 Apr 2030Not yet verified
Important This page is general guidance only. Legionella risk varies with the specific water system, its use, and the people exposed to it. You should consult a competent legionella risk assessor for advice on your premises. LegionellaCheck is an independent information service and is not affiliated with HSE, UKAS, the Legionella Control Association, or any water hygiene company. This site does not provide medical advice. If you suspect Legionnaires' disease, contact NHS 111 or your GP.