What Guardian Water Treatment Ltd. does

Guardian Water Treatment Ltd. is a UK-based specialist outsourcing provider of water treatment and air hygiene services, headquartered in Basildon, with a concentrated operational focus on the South East and London. The company delivers an integrated suite of services spanning legionella risk assessment and control, closed-circuit and cooling-tower water treatment, steam boiler treatment, pre-commissioning cleaning, indoor air quality monitoring, and ventilation/ductwork cleaning, primarily to facilities management providers, building owners, landlords, local authorities, construction firms, and a broad set of verticals including healthcare, education, residential, industrial, hospitality, and data centres. Customers range from individual residential landlords to iconic London commercial developments, with the 122 Leadenhall Street (Cheesegrater) engagement covering 50 floors and 125+ closed systems cited as a flagship project.

The company's technology stack centres on four proprietary or partnered systems. BG50i provides real-time, 24/7 intelligent monitoring of closed-circuit HVAC systems, sampling corrosion indicators, dosing levels, water condition, pressure, and temperature every 15 minutes, and is integrated with Hevasure real-time corrosion monitoring hardware. BG29i offers real-time monitoring for pre-commissioning cleaning of closed-loop systems. Wallenius AOT is a patented photocatalytic advanced oxidation technology that delivers non-chemical water treatment, certified to kill 99.999% of Pseudomonas and Legionella bacteria and WRAS approved. GuardianCare Online is the company's proprietary real-time reporting and legionella control log book, designed to integrate with SFG20 and broader CAFM/BMS platforms.

Guardian operates a direct enterprise field-sales model, supplemented by subcontracting relationships with FM providers and direct engagement with construction firms during the build phase. Revenue is generated primarily through professional services contracts (risk assessments, treatment programmes, remediation cleaning) and a growing layer of recurring monitoring subscriptions via BG50i/Hevasure, with pricing quote-based and scoped to building size and system complexity. The company operates as part of the WCS Group within the broader Marlowe Environmental Services/Marlowe Critical Services platform, giving it cross-sell reach into fire, security, air quality, asbestos, and H&S consulting workstreams. Quantified client outcomes cited by the company include £100,000 in estimated savings at the Cheesegrater building, an 80% reduction in chemical usage at Pilkington Glass with £12,000 in annual chemical cost reduction, and 100% Pseudomonas kill rates with bi-annual rather than bi-weekly maintenance.

Name

Guardian Water Treatment Ltd.

Legal name

Guardian Water Treatment Ltd.

Website

https://gwtltd.com

Company type

Private

Founded year

2015

Operating status

Operating

Short description

Guardian Water Treatment Ltd. is a UK-based water treatment and air hygiene specialist outsourcing provider, part of Marlowe Environmental Services / WCS Group, serving facilities managers, building owners, landlords, local authorities, and construction firms across commercial, healthcare, education, industrial, residential, hospitality, and data centre sectors in the South East and London.

Ownership category

akta.pro rank

Product category

Water Treatment Services

NAICS

Water, Sewage and Other Systems (2213), Remediation Services (562910)

SIC

Sanitary Services (4950), Services-Commercial Physical & Biological Research (8731), Specialty Cleaning, Polishing And Sanitation Preparations (2842)

akta.pro primary industry

Water, Air Quality & Environmental Hygiene (Legionella/IAQ) (BPABAAAO)

akta.pro secondary industries

Legionella Risk Assessment & Compliance Audits (BPABAJAA), Cooling Tower & Evaporative Condenser Water Treatment (BPABAJAC), Monitoring & Control (Dosing Systems, Remote Monitoring, Sensors) (BPABAJAK), Disinfection & Remedial Works (Chlorination, Thermal, Shock Treatments) (BPABAJAF)

Keywords

• Water treatment services
• Legionella control
• Air hygiene services
• HVAC water treatment
• Cooling tower treatment

Headquarters

HQ city

Basildon

HQ country

United Kingdom

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Supply Chain

Revenue model

1. Water Treatment Services: Professional services for water hygiene and treatment including legionella control, legionella risk assessments, cooling tower treatment, closed water systems, steam boiler treatment, and chemical water treatment. Delivered by qualified engineers with services ranging from one-off risk assessments to ongoing maintenance contracts.
2. Air Hygiene Services: Services including indoor air quality monitoring, air hygiene assessment, kitchen extract cleaning, and ventilation ductwork cleaning.
3. Pre-commissioning Cleaning: Cleaning services for new water system installations and remediation cleaning of existing systems, including closed-loop pre-treatment cleaning (CPC) and HVAC corrosion monitoring.
4. Monitoring Technology Services: Real-time monitoring technology packages including BG50i intelligent monitoring and Hevasure corrosion monitoring systems, offered as one-off health checks or ongoing support contracts.

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels5 records

Core offering

Guardian Water Treatment Ltd. delivers water treatment and air hygiene specialist outsourcing services for commercial, public sector and residential buildings across the UK. The company provides legionella risk assessments and control, cooling tower treatment, closed water system treatment, steam boiler treatment, pre-commissioning cleaning, indoor air quality monitoring, kitchen extract cleaning and ventilation ductwork cleaning, supported by proprietary real-time monitoring technologies (BG50i, BG29i, Hevasure, GuardianCare Online) and the patented Wallenius AOT non-chemical water treatment system.

Product overview

Guardian Water Treatment Ltd. provides an integrated portfolio of water treatment and air hygiene services for commercial and residential buildings across the UK. The company's core offerings include the BG50i intelligent water monitoring and treatment package featuring 24/7 real-time corrosion monitoring through Hevasure technology, and the Wallenius AOT non-chemical water treatment system using photocatalytic technology to kill 99.999% of bacteria. Supporting services include legionella control and risk assessment, cooling tower treatment, closed water systems treatment, pre-commission cleaning, and indoor air quality monitoring. The company operates through GuardianCare Online for real-time reporting. Services span from construction and pre-commissioning through to ongoing maintenance, covering sectors including facilities management, education, healthcare, hospitality, and data centres. Guardian is part of Marlowe Environmental Services Group.

Differentiator

Problem solved

Functional benefit

Brands

• GuardianCare: Unique online reporting system and legionella control log book for real-time viewing of works relating to all water systems.
• BG50i
• BG29i
• Wallenius AOT

Products and services

• Legionella Control Services Comprehensive legionella risk assessment, control measures and ongoing monitoring services delivered in compliance with ACoP L8 guidelines for facilities management, healthcare, education, industrial and public sector clients.
• Cooling Tower Water Treatment Treatment services for cooling towers to prevent legionella, scale, corrosion and fouling in open circuit systems at industrial and commercial sites.
• Closed Water Systems Treatment Treatment services for closed-circuit water systems including heating and cooling systems to prevent corrosion and bacterial growth.
• Steam Boiler Water Treatment Chemical water treatment for steam boilers to control scale, corrosion and fouling in industrial boiler systems.
• Pre-commission Cleaning Services Cleaning services for water systems including closed-loop pre-treatment cleaning (CPC), HVAC corrosion monitoring, and remediation cleaning of existing systems during construction and fit-out phases.
• Indoor Air Quality (IAQ) and Monitoring Assessment, monitoring and treatment services for indoor air quality including temperature, carbon monoxide, carbon dioxide, relative humidity, airborne dust particulates, and airborne fungus and bacteria.
• Ventilation and Ductwork Cleaning Air hygiene services including ventilation cleaning and ductwork maintenance to prevent fire risk and remove airborne pathogens.
• Kitchen Extract Cleaning Cleaning of kitchen extract systems for hospitality and commercial kitchen clients to maintain fire safety and hygiene compliance.
• BG50i – Intelligent Water Monitoring and Treatment Trailblazing approach to closed circuit HVAC system management with real-time, 24/7 condition monitoring. Monitors corrosion indicators, water condition, system integrity including dosing levels, unplanned events, pressure and temperature. Available as one-off health check or ongoing monitoring support.
• Wallenius AOT (Advanced Oxidation Technology) Patented non-chemical photocatalytic water purifier that kills bacteria without the use of biocides. Uses specific frequency of light together with photocatalytic semiconductor surfaces to produce free radicals that break down harmful micro-organisms. Proven to kill 99.999% of Pseudomonas and Legionella bacteria, WRAS approved.
• BG29i – Real-time Monitoring Pre-commission Cleaning Intelligent pre-commission cleaning solution with real-time monitoring capabilities for closed-loop systems, ensuring new HVAC systems are contaminant-free from the outset.
• Hevasure Corrosion Monitoring Real-time corrosion monitoring system that monitors corrosion indicators, water condition and system integrity including dosing levels, unplanned events, pressure and temperature every 15 minutes, 24/7.
• GuardianCare Online Reporting Unique online reporting system and legionella control log book allowing real-time viewing of works relating to all water systems, eliminating waiting for paperwork.
• Legionella Training Courses Legionella training courses providing awareness of bacteria and its causes in accordance with ACoP L8 requirements. Includes courses for Facilities Managers, Building/Maintenance Engineers, and specific applications such as cooling towers.

Quantifiable outcome

• £12,000 annual reduction in chemical costs at Pilkington Glass
• +5 more outcomes

Named customers3 records

Segments9 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration4 records

Feature5 records

Partnerships

One partnership is on record.

• WCS GroupcoreStrategic or Co-development PartnerGuardian is a proud member of the WCS Group, the leading water treatment, water and air hygiene and asbestos specialist. WCS Group is a Marlowe Critical Services company comprising water and wastewater treatment & hygiene, fire life safety & security, air quality & testing, and health & safety consulting. The group has 1200+ staff nationally.

Scale indicators3 records

Recent moves7 records

Expansion highlights7 records

Direct peers

• BES (Bio-Energy & Environmental Services): UK specialist in water treatment, Legionella control, and air hygiene services for commercial and public sector buildings. Closely comparable in service mix, customer segments (FM, healthcare, education), and regulatory compliance focus.
• Hydrosphere (UK water treatment): UK provider of water treatment chemicals, Legionella risk assessments, and closed-loop system services for commercial buildings. Direct competitor for chemical water treatment and pre-commissioning cleaning work.
• ChemAqua: Water treatment specialist offering Legionella control, HVAC water treatment, and chemical-free treatment options including closed-loop water management programs. Direct competitor to Guardian in the UK commercial building water hygiene segment.
• WCS Group: Direct parent/partner within Marlowe Critical Services, providing overlapping water treatment, water hygiene, and air hygiene services across the UK. Closely comparable in service lines and customer base given Guardian operates as a specialist subsidiary within this group.
• Hockley International: UK manufacturer and supplier of water treatment chemicals and Legionella control products for commercial HVAC and closed-loop systems. Comparable in regulated water hygiene chemical business, though more product-centric than Guardian's service-led model.
• Clearwater Technology (Marlowe): Sister Marlowe Environmental Services subsidiary delivering water treatment, Legionella control, and hygiene services for UK commercial buildings. Directly comparable in offerings and target FM/healthcare/industrial segments.

Broad incumbents

• Suez Water UK: Major water and waste services operator in the UK providing industrial water treatment, Legionella risk management, and water hygiene services as part of a much larger utility and environmental services platform.
• Veolia Water Technologies UK: Large incumbent water treatment and process water services provider serving industrial, commercial, and municipal customers in the UK. Offers overlapping Legionella control and cooling tower treatment within a much broader environmental services portfolio.
• Nalco Water (Ecolab): Global water treatment services business providing cooling tower, boiler, and closed-loop treatment programs for commercial buildings. Comparable offerings in non-chemical oxidation, monitoring, and managed water hygiene services, but at much larger global scale.

Emerging players

• Phigenics: US-based water management and Legionella risk management services firm expanding into analytics-driven water safety programs for commercial buildings. Comparable in regulated water hygiene and compliance focus, though operates across different geographies.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat6 records

Key risks5 records

Key highlights6 records

Customer concentration

• Xtwitter.com/gwtltd
• LinkedInlinkedin.com/company/guardian-water-treatment

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles3 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Guardian Water Treatment Ltd.