Monitoring & Digital

    Water Quality Testing and Monitoring

    Find the right water quality testing and monitoring partner for your project. Aguato connects procurement teams, project engineers, and sustainability managers with verified providers worldwide. Browse the listings below, or post your project to receive tailored proposals directly from matched suppliers.

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    ABC Stainless Ltd logo

    ABC Stainless Ltd

    United Kingdom

    ABC Stainless Ltd (formed in 1981) are a specialist stainless steel company, offering a full range of services including design, manufacture, supply, installation and commissioning to main contractors and Water Authorities, in the Water Industry. We supply a diverse range of stainless steel products to both WTW and WwTW, including our unique ‘Weldless Collar Pipe System’. This system minimises site fabrication and attendance, supplying prefabricated pipe spools for installation. We welcome enquiries relating to both sheet, plate & tube in all grades of stainless steel including exotic and aluminum, manufacturing stainless steel pipework systems (metric, schedule, dairy etc.), biogas systems, hygienic tanks, pressure & vacuum vessels, platforms, launders, pen stocks, screens, skid process units, weirs etc. DWI Approval We have ISO 9001:2008 accreditation and Drinking Water Inspectorate (DWI 56.4.516) manufacturing approval for our ‘Weldless Collar Pipe System’, and ABC Storage, Process Tanks & Vessels, this is under regulation 31(4)(a) of the Water Supply (Water Quality) regulations 2000 No.3184 & the Water Supply (Water Quality) regulations 2001(Wales) No.3911. In all cases, products are manufactured specifically for each project after full discussion with our clients and our own design office. We offer a full design & draughting service using the latest 3D modelling software. Material certification, quality plans, procedures, employee certification and testing are available upon request, with third party Insurer witness testing where required. We offer a range of material finishes including bead blast, bright (mirror) polished, satine (brushed) polished and 2B.

    Renewables & Energy Management
    Accreditations
    IIES (Northern) Ltd logo

    IIES (Northern) Ltd

    United Kingdom

    IIES (Northern) Ltd design, manufacture, install and commission chemical dosing systems in the water industry. IIES (Northern) was established in 1985 as an ICA, electrical and mechanical engineering company generally serving the water industry as a specialist chemical dosing provider. Since then we have developed into a multi-disciplined project engineering company involved in all aspects of engineering with the majority of our business still water related.  The company has been engaged and responsible for successful delivery of over 1800 projects in our markets. IIES has a formidable record of completing outstanding projects in the water treatment industry for over 40 years which support strict environment and regulatory compliance requirements, all backed up with management systems accreditation in ISO:9001, ISO:14001 and ISO:45001.  We are also certified on Achilles UVDB, Construction Line, ECA and are an approved contractor on NICEIC. Our core capability encompasses the following: CHEMICAL DOSING & TECHNICAL CONSULTANCY Site surveys 3D scanning available Process investigation Process recommendations Compliance with standards & specifications MANUFACTURE & INSTALLATION Plastic fabrication Plastic cutting Plastic welding Chemical dosing systems Chemical dosing rigs Bunds/drip trays Kiosks & enclosures Electrical installation NICEIC approved contractor Control & instrumentation cabling Pipework installation Fusion welding Delivery and offloading Site installation MEICA DESIGN Mechanical Process instrumentation & piping diagram Process calculations Full site general arrangements Equipment general arrangements Schedules and standards Full operation & maintenance manuals Electrical Process and systems control philosophies Cable block diagrams Schedules Electrical installation to BS7671 Test and inspection to BS7671 Electrical certification NICEIC approved Member of the ECA Control Panel design FDS Panel schematics System Integration PLC software HMI software SCADA integration Telemetry integration COMMISSIONING & SITE PROCESS SET-UP System setup Pressure testing Electrical installation testing Electrical certification (NICEIC) Servicing & maintenance Telemetry & SCADA OTHER SPECIALIST AREAS Control panel specification P & ID development Front end design & feasibility Capital/revenue budget costing Equipment specifications Detailed design & construction packages Project management Operating & maintenance documents Principal contractor Offsite testing Development of plant layouts Process & equipment specifications From initial client briefing a basis of design, including site surveys as necessary, will be carefully prepared and reviewed and will be developed further through detailed specifications and arrangement drawings. Our experienced engineers can provide comprehensive installation design for a variety of process plant and equipment, handling hazardous bulk chemicals in liquid, gaseous or solid form and in extreme conditions. Technical review and support will be provided to the client throughout the development cycle.

    Health & Safety
    Accreditations
    PBA Applied Ecology Ltd logo

    PBA Applied Ecology Ltd

    United Kingdom

    PBA Applied Ecology Ltd has unparalleled experience in the environmental planning and practical management of water engineering schemes and in-channel river works. We have earned an outstanding reputation for delivering projects on time, on budget and to the satisfaction of all stakeholders. Our strength is Applied Ecology – the practical and innovative application of life sciences to real life situations. We assist with the planning and delivery of a range of water engineering schemes including reservoir engineering, catchment restoration and wetland creation, and are acknowledged for the successful completion of large scale projects on highly sensitive sites (SSSI, SAC). PBA offer a full range of services including baseline ecological survey, planning/consents, method statements, fish rescue, surface water management, water quality monitoring & control, invasive non-native species identification and control, biological monitoring, restoration design and delivery. Where appropriate, we apply protocols that are fully compliant with UK-wide delivery of Water Framework Directive. A frequent cause of stress amongst project teams is ensuring the maintenance of ecologically acceptable flow and water quality, and that impact on fish and other biota are minimised. PBA assist you in managing these aspects of water engineering projects. At the outset of each project, we can assist in agreeing achievable and ecologically acceptable water quality standards with regulators. Our staff then monitor, advise on containment works, and liaise with regulators throughout. PBA’s working methods are designed towards most efficient project delivery with minimum environmental impact. Engaging our specialist knowledge at an early stage of project design can help to ensure that the project is completed on time, on budget, and with enhanced conservation benefits. PBA deploy structured teams of professionals, to robustly deal with every challenge, from project conception, to aftercare management. And most importantly, we do this with safety as our No.1 priority. All of our staff are fully trained and equipped, and also attend PBA’s own water safety training/first aid course every year.

    Mapping & Modelling
    Wildlife Rescue & Relocation
    RSE Controls (Blackburn Starling) logo

    RSE Controls (Blackburn Starling)

    United Kingdom

    RSE Controls (Blackburn Starling) is an automation solutions provider and manufacturer of bespoke LV control systems including both conventional and intelligent motor control centres, switchboards, package substations, containerised equipment and instrumentation panels. The company has extensive systems integration capability including MIS/MES, SCADA and PLC programming. Scope of supply includes site surveys, full in-house design and technical support service, project management, product manufacture (including metal fabrication), software programming, test, installation, commissioning, training, maintenance, equipment refurbishment and modification. RSE Controls (Blackburn Starling) is a well respected company with a trading history of almost 150 years. The company offers an unrivalled combination of experience and capability and is a major provider of motor control centres into the United Kingdom. RSE Controls (Blackburn Starling) has supplied its products and services into the water sector in the UK for more than 50 years and has Framework Agreements directly with many UK Water PLCs. The company has an excellent reputation within its industry sectors and is renowned for being reliable and honourable. RSE Controls (Blackburn Starling) is located on a 4 acre site in the Midlands area of the UK. The company operates its own design and manufacturing facility and a key strength of the company is the provision of complete in-house capability to cover all aspects of design, metal fabrication (including laser cutting), paint, assembly, copper, wiring, testing, delivery and installation (using our own hi-ab equipped lorry), commissioning, maintenance and training, ensuring we have full control of the design and manufacture of the entire scope of works. Product innovation and technical excellence are paramount and tailoring control systems to the special needs of its customers is RSE Controls (Blackburn Starling)’s greatest strength.

    Networks - Water Supply
    Contractors
    Weber Sensors Ltd logo

    Weber Sensors Ltd

    United Kingdom

    The Captor Group supplies an extensive range of sensors specifically for the needs of water and wastewater treatment. Dosing systems, flow monitoring, pump protection and air monitoring are only a few of the applications where our sensors are constantly meeting industry needs. From large pipe sewage applications down to the smallest of flow rates involving the most aggressive of chemicals, we can provide for all your flow sensing requirements. FLOW CAPTORS: High-precise, compact and robust flow sensor for monitoring liquid media (switch or meter). VENT CAPTORS: Compact, electronic sensor for monitoring air and other gaseous media (switch or meter). FOTO CAPTORS: Hot metal detector (HMD) which operates properly and even reliably even under rough working conditions. For applications in steel mills. PROXI CAPTORS: Inductive proximity switches and meters for detection in the steel industry. For switching distances up to 250mm. POWER SUPPLY UNITS: Power supply unites for use with flow and vent captor products requiring 24 VDC supply. PROCESS INPUT METERS: This process meters convert the analogue output signal of flow and vent-captor units into a digital value.

    Control & Automation
    3rd Light Media Ltd logo

    3rd Light Media Ltd

    United Kingdom

    3rd Light Media provide technical documentation and design services for water and wastewater projects, both in the UK and internationally. We provide a range of documentation for projects, helping clients achieve their handover requirements and producing high quality documents which provide the end users with the information they need to operate and maintain the plants. We are a market leader in driving digital innovative solutions to our clients to ensure documentation is presented in new and dynamic ways, this includes development of web-based O&M manuals which can integrate with client I.T. systems such as SharePoint; Graphical design to enable data and documentation of assets on a site plan or P&ID to be available within just a few clicks of a button. Additionally, we have developed a QR coded asset tagging system and mobile App. Our services mean we can provide our clients with a single source for all handover documentation requirements. The services we can provide include: Operating and Maintenance Manuals (O&Ms) Site Operating Manual (SOM) Health & Safety Files Asset Data Registration Training Manuals Site Drawings (P&IDs, Process Flows, Site Layouts and Plans, GA’s, Single Line Diagrams and more) AutoCAD Drafting Services Additionally, we also provide a range of onsite services to further enhance being a one stop provider for all your project handover needs. Some of the onsite services we provide include: Asset Identification Tags (to meet all individual client specifications) Pipe Banding to BS1710 Site signage and labelling We also provide a range of design and pre-construction services, with experience when working with Tier 1 contractors at ECI / Outline Design stages of projects including: Functional Design Specifications Control Philosophies Factory Acceptance & Site Acceptance Tests for Software Testing Commissioning Plans and Sequencing Asset Condition Reports Verification Survey Works (Producing P&IDs, ICA and Electrical Design Proposals) We work as an integrated team with both contractors and clients to ensure all aspects of project handover are achieved to the highest standard. We are able to do this with our vast knowledge of individual water companies asset standards and specifications. We are also experienced in using portals such as TWEXnet, Asite, Aconex, Business Collaborator and Conject for uploading documents. Our team comprises of skilled and experienced site and process engineers with a vast knowledge of both water and wastewater treatment systems. Our team of engineers all hold EUSR Water Hygiene and CSCS cards as well as water company specific requirements such as the Thames Water Safety Passport. We also have an in-house graphic design team providing professionally drawn illustrations and drawings which are used within our documentation, helping to visualise written descriptions and processes. Our philosophy is to take the burden of producing documentation on projects away from our clients. Being skilled process engineers, we will visit sites to gather information and we work with your supply chain to coordinate the availability of all required documents and drawings, ensuring compliance with the end clients standards. We write all the technical content and detail to the highest standard, supported by expertly drawn diagrams and illustrations. Some of the water companies we have worked with include: Thames Water Affinity Water Yorkshire Water Southern Water Severn Trent South East Water United Utilities Welsh Water Bristol Water Essex & Suffolk Water Irish Water Haya Water We work both directly with water companies and Tier 1 and Tier 2 contractors. We work on projects of all sizes, from minor schemes to major £100+ million projects.

    Treatment Works Products/Services
    Accreditations
    Lloyd Morris Electrical Ltd logo

    Lloyd Morris Electrical Ltd

    United Kingdom

    Lloyd Morris Electrical Limited is a company of electrical engineers, specialising in the design, manufacture and installation of electrical distribution and control systems for industrial and commercial applications. Having established the company in 1974, it has since developed in to a well-recognised and reputable organisation within the industry and is keen to develop professional and pro-active relationships with its clients. LME offers Design for Manufacture and Assembly (DfMA) across the complete electrical service supply. The off-site manufacture of pre-assembled and cabled low voltage switch/plant rooms offers significant benefits in relation to safety, quality, cost and program. Control panels LME pride ourselves in being at the forefront of control panel manufacturing. LME have an unrivalled level of expertise and service, and we make sure that all our control panels are designed and built to match your exact requirements. LME provide control panels constructed from Form 1 through to Form 4. With our control panels we consider the space available and all special site requirements. We can supply off the shelf or bespoke steelwork so that each order can be custom built to specific requirements and comply with your general and exact specifications. Intelligent design motor control centres minimise the number of components required as various functions are integrated into single intelligent devices. LME offer intelligent motor control centres manufactured to the same construction range as our conventional units which are all bespoke and are BS EN61439-1&2 compliant. LV switchboards LME manufacture bespoke LV switchboards, each assembly can be custom built to specific requirements and comply with client’s exact specifications providing LV switchboards constructed from Form 1 through to Form 4, Type 1 to Type 7. With our LV switchboards, we can accommodate various types of cable entries whether top, bottom or a mixture of both, front or rear access, or we can even manufacture a hybrid solution using a combination of any form and type. Electrical design An important aspect in the development of any project is the design and provision of professionally presented documentation. Therefore, to meet the varying needs of each client, our team of draughtsman are well equipped with the latest AutoCAD systems. Our project engineers use software tools to perform cable and lighting calculations, cable and instrumentation scheduling, rating of protection devices, and overall contract programming and scheduling. Electrical installations LME have the resource, capability, and experience to provide a complete electrical installation, for any water plant or factory. With a large, fully qualified, and competent workforce combined with an extensive fleet of vehicles, no task is too large and no location too remote. With this structure and experience, we can offer a comprehensive range of installation services covering locations throughout the United Kingdom. Systems integration To provide a fully integrated approach to projects, the company has the facility to develop complex and highly structured software. Our systems engineers have considerable experience in all aspects of software design and development, ranging from basic PLC systems and HMI/SCADA, controlling process and manufacturing plant, through to commercial and industrial databases and high-level management information systems (MIS), producing essential business information.

    Networks - Sewerage
    Accreditations
    Power Plastics Ltd logo

    Power Plastics Ltd

    United Kingdom

    Power Plastics Ltd, an ISO 9001 certified company, design, manufacture and install a range of flexible roofing systems for process tanks extensively used within the water and sewage industry. Their roofs are manufactured from tough high quality reinforced PVC materials supported on skeletal frames manufactured from aluminium, galvanised steel or stainless steel. The covers can be designed to be easily removed and refitted within minutes by one or two people without the need for specialist equipment giving unrestricted access to the tank process. This has great benefits in respect to monitoring and maintaining the tank process in addition to the added health safety benefits associated with a confined spaces issues. The roofs can be used for many purposes with materials being suitable for contact with drinking water and being resistant to corrosive materials. All their installations are carried out by highly skilled fittings teams which are overseen by project managers, who ensure that all health and safety issues have been considered in addition to providing thorough risk assessments and method statements prior to commencing any work on site. All designs are structurally proven by independent structural engineers and comply with the latest CDM regulations.

    Designers
    Pump Supplies Ltd logo

    Pump Supplies Ltd

    United Kingdom

    At Pump Supplies, our mission is simple. We aim to lead the way in both innovative pump solutions and customer satisfaction. We believe that our success is driven by the success of our customers. That’s why we’re dedicated to delivering services that not only meet but exceed expectations in functionality, durability, and cost-efficiency. Products We offer a comprehensive range of submersible pumps, including drainage, sewage, and slurry pumps. Each product is selected for its quality and performance, ensuring you receive the best possible equipment for your specific needs. Services Beyond our extensive product range, we provide full-service solutions encompassing installation, maintenance, and repair. Our team of experts is equipped with the knowledge and tools to ensure your pumping systems operate smoothly and reliably. Custom solutions Understanding that each setting has its own unique challenges, we specialise in creating custom pump setups tailored to your specific operational requirements. Our engineers work closely with you to design systems that not only perform well but also contribute to your operational efficiency. We will also work alongside you when it comes to the monitoring and control of your pumping equipment

    Treatment Works Products/Services
    Designers

    Water Quality Testing and Monitoring: Analytical Methods, Accreditation, and Compliance Sampling

    Water quality testing and monitoring encompasses laboratory analysis, field sampling, and continuous online monitoring to characterise source water, verify treatment performance, and demonstrate regulatory compliance. UK drinking water regulatory monitoring is prescribed by the Water Supply (Water Quality) Regulations 2016 (England) and equivalent Regulations in Wales, Scotland, and Northern Ireland; monitoring requirements are set by the DWI (Drinking Water Inspectorate) through water company monitoring programmes; parameters monitored include: microbiological (E. coli, total coliforms, Clostridium perfringens, Cryptosporidium oocyst count, enterococci, colony counts at 22 and 37 degrees C); chemical (turbidity, colour, pH, conductivity, TOC, THMs, nitrate, nitrite, lead, copper, iron, manganese, fluoride, aluminium, bromide, chloride, sulphate, sodium, ammonium, pesticides, PAHs, PFAS); radiological (tritium, total indicative dose); sampling locations: source water, at treatment works, and at a statistical sample of consumer taps (DWI sampling protocol: random daytime sampling (RDS); fixed point sampling; regulatory tap samples tested at EA/DWI accredited laboratory). Laboratory accreditation: UKAS ISO/IEC 17025 accreditation is required for all laboratories analysing drinking water samples for regulatory purposes in the UK; UKAS schedule of accredited testing includes all methods used (APHA Standard Methods, ISO methods, BS EN methods, EA Method UK); EA works with MCERTS (Monitoring Certification Scheme) for environmental water analysis; MCERTS accreditation covers: water quality parameters (ISO 17025); continuous emission monitoring systems (CEMS); soil analysis.

    Analytical methods for key water quality parameters: microbiological: E. coli and total coliforms by membrane filtration (BS EN ISO 9308-1; Colilert-18 defined substrate method; incubation 37 degrees C, 18 hours; reading MPN or colony count); Cryptosporidium oocyst detection by US EPA Method 1623.1 or BS EN 14764 (12 to 24 L sample through membrane filter; immunomagnetic separation (IMS); immunofluorescence assay (IFA) with DAPI and DIC microscopy; confirmation of oocysts by morphology and fluorescence; detection limit 0.01 to 0.1 oocysts/L); chemical trace organics: THMs (chloroform, bromoform, BDCM, DBCM) by EPA Method 524.3 or ISO 11423-1 (headspace GC-MS; detection limit 0.1 to 1 ug/L; UK regulatory standard: THM sum 100 ug/L); pesticides (triazines, organophosphates, chlorophenoxy herbicides) by EPA Method 8270 or EN 12823 (GC-MS or LC-MS/MS after liquid-liquid extraction; detection limit 0.01 to 0.1 ug/L; UK PCV 0.1 ug/L individual, 0.5 ug/L sum); PFAS by EPA Method 537.1 or ISO 21675 (solid phase extraction (SPE) concentration; LC-MS/MS quantification; detection limit 0.1 to 1 ng/L for each PFAS; sum 22 PFAS UK standard 100 ng/L); heavy metals (Pb, Cu, Ni, Cr, Cd, As) by EPA Method 200.8 or EN ISO 17294-2 (ICP-MS; detection limit 0.01 to 0.1 ug/L; UK lead standard 10 ug/L; WHO guideline 10 ug/L); online continuous: turbidimeters (ISO 7027; 850 nm LED; 0.001 to 1,000 NTU; at filter outlets and distribution); free chlorine residual (amperometric or DPD colorimetric; 4 to 20 mA output to SCADA; 0.05 to 2.0 mg/L Cl2 range; DWI minimum 0.1 mg/L free chlorine at service reservoirs).

    Environmental water monitoring: EA and SEPA monitor surface water quality under the Water Framework Directive (WFD) / Environmental Targets (Water) Regulations 2022 to assess ecological and chemical status (good ecological status target for all water bodies by 2027); WFD monitoring types: surveillance monitoring (representative water body sites; annual sampling for all priority substances; 3 to 6 year cycle); operational monitoring (water bodies at risk of failing objectives; higher frequency, targeted to pressures); investigative monitoring (where causes of failure are unknown). MCERTS-certified automatic water quality monitoring stations (AWQMS) on rivers measure online: dissolved oxygen (DO, optical sensor, 0 to 20 mg/L), temperature, pH, conductivity, turbidity, ammonia (ion-selective electrode or spectrophotometric), nitrate (UV absorbance at 220 nm), TOC/DOC (UV-persulphate oxidation); data transmitted to EA WISKI or Hydstra LIMS every 15 minutes. Groundwater monitoring: EA Groundwater Level (GWL) network of approximately 5,000 dip wells and pressure transducer loggers (hourly or daily frequency); groundwater quality chemistry monitoring at EA compliance sites: quarterly for nitrates and pesticides; six-monthly for metals and VOCs; annual for PFAS (expanding monitoring under EA Groundwater Protection Policy 2022). ISO/IEC 17025 calibration: all field instruments (dissolved oxygen probes, pH meters, conductivity meters, turbidimeters) must be calibrated at defined intervals using UKAS-traceable calibration standards; calibration records maintained for 7 years (DWI requirement); field blanks and duplicates taken as QA/QC evidence.

    Frequently Asked Questions

    How often is UK tap water tested and what is measured?

    UK tap water testing frequency is prescribed by the Water Supply (Water Quality) Regulations 2016 (England) and equivalent regulations in Wales, Scotland, and Northern Ireland. Monitoring frequency depends on the population served by the water supply zone (WSZ): small zones (less than 100 properties): some parameters tested monthly; large zones (greater than 500,000 population): some parameters daily. Key monitoring categories and frequencies: (1) Microbiological: E. coli and total coliforms at treatment works and in distribution: at least weekly for zones greater than 10,000 population; turbidity at all treatment works: continuous (online turbidimeter); Cryptosporidium: continuous monitoring at all treatment works abstracting surface water or groundwater under the direct influence of surface water (GWUDI); (2) Physical/chemical: colour, turbidity, conductivity, pH: minimum weekly in distribution; THMs, aluminium, iron, manganese, nitrate: monthly in distribution for large zones; annually for small zones; (3) Extended parameters (pesticides, PFAS, PAHs, heavy metals including lead at consumer taps): lead tested under the regulatory tap sampling programme (random daytime sampling (RDS) at consumer properties; minimum number of samples per zone determined by DWI; any result greater than 10 ug/L Pb triggers investigation and action); (4) Taste and odour: no numerical regulatory standard; DWI requires 'taste and odour acceptable'; tested by trained panel (ISO 8586 sensory assessors) or consumer complaint response. All results reported in water companies' annual monitoring returns to DWI; DWI publishes summary in annual Drinking Water Quality in England report; any serious event or breach of PCV (Prescribed Concentration or Value) must be reported to DWI within 30 days.

    What laboratory accreditation is required for water testing in the UK?

    UKAS ISO/IEC 17025:2017 accreditation (UKAS, UK Accreditation Service, the national accreditation body for the UK) is the primary accreditation required for laboratories carrying out regulatory water quality testing. Scope: UKAS accreditation covers specific analytical methods for specific matrices (e.g. 'determination of E. coli and total coliforms in drinking water by membrane filtration (BS EN ISO 9308-1:2014+A1:2017)'); laboratories must demonstrate competence in each accredited method through: proficiency testing (PT) schemes (WaterPT, Food and Environment Research Agency FAPAS, RSSL PT scheme; laboratories must perform satisfactorily in PT rounds, typically bi-annual participation; z-score less than 2.0 for 95 percent of results); internal quality control (IQC: blank, duplicate, and spiked sample analysis on each analytical batch; control charts maintained; action limits and warning limits); method validation documentation; equipment calibration traceable to SI units (UKAS-traceable calibration from NPL National Physical Laboratory standards); staff competence assessment. EA MCERTS: Environment Agency Monitoring Certification Scheme; additional to ISO 17025 for environmental monitoring; MCERTS certification required for: drinking water treatment chemical analysis; effluent analysis for Environmental Permit compliance reporting; continuous emissions monitoring. Accreditation schedule: UKAS laboratory schedule lists every accredited test by method reference (BS EN ISO, EPA, APHA Standard Methods) and includes scope limitations; check at ukas.com/find-an-accreditation-body/accredited-organisations. DWI requirement: companies must use UKAS-accredited laboratories for all regulatory monitoring under the Water Supply (Water Quality) Regulations 2016; non-accredited laboratories may be used for operational monitoring (non-regulatory) but results cannot be used for DWI compliance reporting.

    What online water quality monitoring instruments are used in treatment works?

    Online continuous water quality monitoring instruments at drinking water treatment works and distribution systems: (1) Turbidimeters: 90-degree scattered light at 850 nm LED (ISO 7027:2016); Hach 1720E (low range 0 to 1 NTU for filter effluents, alarm at 0.2 NTU per DWI guidance), TurbiMax W by Endress+Hauser, Partech SE500; calibrated with Formazin primary standard (AMCO-AEPA secondary standard); DWI requires turbidity less than 0.1 NTU (100 percentile) and less than 1 NTU (99th percentile) at treatment works outlet for surface water sources. (2) pH: glass electrode combination sensor (Endress+Hauser CPS11D, Mettler Toledo InPro4010SG; range pH 0 to 14; ATEX-rated versions available; calibrated with two NIST buffer solutions (pH 4.01 and pH 7.00); DWI pH 6.5 to 9.5 in distribution). (3) Free chlorine residual: Hach CL17sc (amperometric, 0.01 to 5.00 mg/L Cl2; calibrated vs DPD colorimetric in-situ); BTG Mutek Chlorotrend (electrochemical, low maintenance); required continuous at all service reservoirs (DWI: minimum 0.1 mg/L free Cl2). (4) UV254 absorbance: Hach UVAS sc; measured as specific UV absorbance (SUVA = UV254/DOC); surrogate for NOM and treatment efficiency; Endress+Hauser SpectraSensors UV sensor; alarmed if UV254 rises (indicates NOM breakthrough or process failure). (5) Conductivity: inductive conductivity sensor (Endress+Hauser Indumax CLS50, no electrodes, no fouling; 0.01 to 2,000 mS/cm). (6) Dissolved oxygen: optical (luminescence quenching, LDO): Hach LDO2 (0 to 20 mg/L; no membrane replacement; ATEX option); used in biological treatment and reservoir monitoring. (7) Ammonia (NH4+): ion-selective electrode (ISE) or photometric (indophenol blue): Hach Amtax sc (0.01 to 1.0 mg/L NH4-N), Endress+Hauser Liquiline system CA80AM; alarmed for breakthrough of ammonium from source water or biological instability.

    What is the difference between regulatory and operational water quality monitoring?

    Regulatory monitoring is the programme of sampling and analysis required by law to demonstrate compliance with the Water Supply (Water Quality) Regulations 2016 (drinking water) or Environmental Permit (wastewater). Characteristics: specified parameters, locations, frequency, and methods defined by regulation; must use UKAS ISO/IEC 17025 accredited laboratory; results reported to DWI (drinking water) or EA (wastewater); any exceedance of a Prescribed Concentration or Value (PCV) is a legal breach requiring DWI notification within 30 days; water company liable to enforcement action if regulatory limits exceeded (DWI can issue undertakings, DWI notices, or refer to criminal prosecution for persistent failures; maximum fine unlimited under Environmental Permitting (England and Wales) Regulations 2016). Operational monitoring (also called process monitoring or in-house monitoring): carried out by the water company to optimise process performance, detect trends, and respond early before a problem affects regulatory compliance; higher frequency than regulatory; may use non-accredited methods (rapid field test kits, online instruments); does not need to use UKAS-accredited laboratory; results not submitted to regulator (but may be reviewed in DWI audits); examples: hourly turbidity at each filter outlet (detect breakthrough immediately); daily chlorine residual checks at multiple distribution points; weekly jar tests for coagulation optimisation; monthly chemical dosing stock checks. Risk-based monitoring: Drinking Water Safety Plans (DWSPs), required by DWI under the WHO Water Safety Plan approach (WSP, WHO 2009), require each water company to conduct hazard analysis and risk assessment of all catchment-to-tap steps; monitoring (regulatory and operational) is designed to verify control measures at critical control points (CCPs); the DWSP approach allows the combined regulatory and operational monitoring to be designed as an integrated system.

    Case Study·Drinking water quality compliance and monitoring
    Challenge

    A water company in the North West supplying 120,000 properties from a surface reservoir source experienced 3 THM failures (chloroform sum peaking at 128 ug/L against the 100 ug/L PCV) in 12 months during periods of high autumn catchment colour (true colour exceeding 80 Hazen units), triggering a DWI enforcement undertaking requiring a corrective action plan within 60 days.

    Approach

    A Drinking Water Safety Plan review identified two critical control point failures: (1) coagulant (ferric sulphate) dosing was controlled manually without online UV254 feedback, causing under-coagulation during colour events; (2) chlorine contact time at the pre-chlorination point was insufficient at high flow, generating elevated THM precursor reaction with residual NOM. The corrective plan installed a Hach UVAS online UV254 analyser driving an automated ferric dosing PID loop, a second coagulant dosing point to increase contact time, and an online THM analyser (Myriad THMplus, sampling from the service reservoir outlet) with a SCADA alarm at 80 ug/L to allow operational intervention before the PCV was breached.

    Outcome

    THM compliance restored within 4 months of commissioning; no further breaches in 24-month post-installation monitoring period. Annual regulatory DWI monitoring returns showed THM average reduced from 84 to 42 ug/L. The automated dosing system reduced ferric sulphate consumption by 18 percent (GBP 28,000 per year saving) and improved turbidity at filter outlets from 0.14 NTU average to 0.07 NTU average, creating additional safety margin. DWI enforcement undertaking discharged at the 18-month review.

    Questions to Ask Shortlisted Providers

    1. 1

      Is your regulatory monitoring programme designed around a risk-based Drinking Water Safety Plan (DWSP) framework, and has it been reviewed by DWI within the last 3 years?

      DWI expects water companies to operate DWSPs aligned with WHO Water Safety Plan principles; a DWSP-designed monitoring programme is accepted by DWI as evidence of systematic risk management at inspections, whereas a monitoring programme based only on the minimum regulatory schedule may not demonstrate adequate control of site-specific hazards such as seasonal THM precursor events or Cryptosporidium risk periods.

    2. 2

      For online process monitoring instruments (turbidimeters, chlorine analysers, UV254 sensors), what is the calibration frequency and what is the sensor response time for alarm conditions?

      DWI guidance expects key online process monitors at treatment works to be calibrated at intervals validated by the company's quality assurance system (typically at least weekly for turbidimeters; at least daily verification for chlorine analysers); a sensor response time exceeding 15 minutes may mean that a treatment failure is not detected before affected water has left the treatment works and entered the distribution system.

    3. 3

      Have all laboratory subcontractors been checked against the UKAS Accredited Organisations schedule for the specific methods used in your regulatory monitoring programme?

      UKAS accreditation is method-specific and matrix-specific; a laboratory accredited for THM analysis in drinking water may not be accredited for the same analysis in raw source water; using a non-accredited method for a regulatory sample produces data that cannot be used for DWI compliance reporting and may result in a failed sample being undetectable or unenforceable.

    4. 4

      How is continuous Cryptosporidium monitoring data from treatment works transmitted to your SCADA system, and what is the alarm response protocol for oocyst detections above the trigger level?

      The Cryptosporidium (Additional Measures) Direction 1999 requires continuous monitoring at qualifying works; the response protocol for an oocyst detection event (typically greater than 1 oocyst per 10 litres triggers an internal investigation, and greater than 10 oocysts per 10 litres may trigger a boil water notice) must be formally documented and staff must be trained to respond within the defined timeframe.

    5. 5

      What quality assurance controls (blanks, duplicates, spiked recovery samples) are applied to your field sampling process, and how are these results recorded and trended?

      Field sampling errors (contaminated sample bottles, incorrect preservation, temperature exceedance during transport) account for a significant proportion of apparent water quality failures at UKAS-accredited laboratories; systematic QA on field sampling (including field duplicate agreement within 10 percent, blank results below method detection limit, and spike recovery within 80 to 120 percent) is required to demonstrate that a reported PCV exceedance reflects actual water quality rather than sampling error.

    What Drives Cost in This Category

    Laboratory analytical costs for regulatory versus operational monitoring

    UKAS-accredited regulatory analysis costs are significantly higher than internal operational testing: PFAS analysis by LC-MS/MS (EPA 537.1) costs GBP 250 to 500 per sample at an external accredited laboratory; an internal field test kit (Hach colorimetric) for free chlorine costs GBP 0.20 per test; for a company with 50 supply zones and quarterly PFAS monitoring, external laboratory costs are GBP 50,000 to 100,000 per year for PFAS alone, justifying investment in internal semi-quantitative PFAS screening methods for operational monitoring.

    Online analyser procurement, installation, and calibration maintenance

    A single Myriad THMplus online THM analyser (GC-based, sampling once per 20 minutes) costs GBP 35,000 to 55,000 installed; annual maintenance (consumables, calibration gas, lamp replacement) GBP 4,000 to 8,000 per year; compared to the cost of a THM compliance failure (DWI enforcement undertaking, public communication, corrective action programme, potential penalties) which routinely exceeds GBP 200,000 per event, the economics of continuous monitoring are straightforward for high-THM-risk sources.

    Proficiency testing (PT) scheme participation and laboratory accreditation maintenance

    UKAS requires accredited laboratories to participate in PT schemes (WaterPT, UKWIR PT) at typically bi-annual frequency; PT round participation costs GBP 300 to 800 per round per parameter group; UKAS surveillance audit fees GBP 3,000 to 8,000 per day (typically 1 to 2 days per year); accreditation renewal GBP 5,000 to 15,000 per 3-year cycle; smaller water company laboratories operating 10 to 20 accredited methods spend GBP 20,000 to 50,000 per year on accreditation maintenance, which must be included in the water quality monitoring budget.

    Contamination event response and incident investigation costs

    A DWI-notified water quality failure (PCV exceedance for a microbiological or chemical parameter) triggers an investigation that typically costs GBP 20,000 to 80,000 in analytical, staff, and communications costs; a boil water notice event serving more than 10,000 properties requires bottled water distribution (GBP 5 to 15 per property per day), customer communications (GBP 20,000 to 80,000), and post-incident DWI reporting; investment in preventive monitoring (online THM, continuous turbidity, Cryptosporidium monitoring) is routinely cost-justified against the expected cost of 1 to 2 averted incidents per decade.

    Key Regulations & Standards

    Water Supply (Water Quality) Regulations 2016 (England) - Monitoring Requirements and PCVs

    WS(WQ)R 2016 Schedule 1 sets Prescribed Concentration Values (PCVs) for 50+ parameters; Schedule 5 sets monitoring frequencies based on population served; Regulation 16 requires results to be reported to DWI; Regulation 19 requires notification of PCV breaches within 30 days; DWI Technical Guidance (TG01 to TG10 series) provides detailed guidance on monitoring methods and quality assurance.

    UKAS ISO/IEC 17025:2017 Accreditation for Regulatory Water Testing

    All laboratories carrying out analysis of regulatory water quality samples in the UK must hold UKAS accreditation for each relevant method; UKAS accreditation schedule is method-specific (identifies each analytical method, scope, and any limitations); UKAS conducts annual surveillance visits and 3-yearly reassessment; failure to maintain accreditation results in withdrawal of authority to report regulatory results to DWI or EA.

    Cryptosporidium (Additional Measures) Direction 1999 - Continuous Monitoring Obligation

    The Direction requires continuous monitoring for Cryptosporidium oocysts at all treatment works abstracting surface water or groundwater under the direct influence of surface water (GWUDI); monitoring must use a validated method (US EPA Method 1623.1 or BS EN 14764); results must be reported to DWI monthly; oocyst detections above defined trigger levels require immediate investigation and possible supply restriction.

    EA MCERTS (Monitoring Certification Scheme) for Environmental Water Quality Analysis

    EA MCERTS certification is required for laboratories and instruments used in analysis of environmental water samples for EA Environmental Permit compliance reporting; MCERTS covers drinking water treatment chemical analysis, effluent analysis, and continuous emission monitoring; MCERTS requirements include ISO 17025 accreditation plus additional EA-specific method and quality requirements; MCERTS certification is separate from and in addition to UKAS accreditation.