Plumbing in the UK sits under a web of overlapping regulation that most plumbers understand in practice but rarely document in full. The Water Supply (Water Fittings) Regulations 1999 set the baseline. Building Regulations Part G and Part H add layer upon layer of compliance obligation for new installations and material changes. Legionella risk assessment requirements under the Health and Safety at Work Act bring a further set of record-keeping duties. And through all of this, the expectation from water companies, local authorities, and increasingly from commercial clients is that the plumber can produce paperwork proving every installation was done to standard.
Most cannot. Not because the work was done badly, but because the documentation systems do not exist in any organised form.
The Water Supply (Water Fittings) Regulations 1999 (SI 1999/1148) apply to every plumbing installation in England and Wales. Scotland has its own equivalent under the Water Byelaws 2014. The regulations exist to prevent contamination, waste, misuse, and undue consumption of water supplied by water undertakers. They apply to anyone who installs, alters, connects, or disconnects a water fitting.
Under Regulation 5, no person shall install a water fitting to convey water supplied by a water undertaker unless it complies with the requirements of Schedule 2. In practical terms, this means every component, from the stopcock to the shower head, must meet the performance requirements set out in the schedule or be listed on the Water Regulations Advisory Scheme (WRAS) Product Directory.
Regulation 5 also requires advance notice to the water undertaker for certain categories of work. Installing a bidet with ascending spray, constructing a pond or swimming pool fed from the mains, installing a reduced pressure zone (RPZ) valve, or any installation in a building over five storeys all require consent from the local water company before work begins. Failure to notify is a criminal offence, prosecutable by the water undertaker.
The Water Regulations Advisory Scheme operates two programmes relevant to plumbers. The WRAS Product Directory lists products and materials that have been independently tested and approved as compliant with the Water Supply Regulations. Using WRAS-approved products is not strictly mandatory, but it is the simplest way to demonstrate compliance. If a product carries the WRAS approval mark, it is deemed to satisfy the material requirements of the regulations without further proof. If it does not, the plumber must be able to demonstrate equivalent compliance through alternative means, which in practice means holding test certificates or manufacturer declarations of conformity.
The second programme is WaterSafe, the approved contractor scheme. WaterSafe plumbers have been assessed as competent to work in compliance with the Water Supply Regulations and can self-certify that their installations meet the regulatory requirements. WaterSafe registration is not legally required, but water companies increasingly expect it, and many commercial contracts specify WaterSafe membership as a condition of appointment. There are over 36,000 approved plumbers on the WaterSafe register.
For WaterSafe members, the compliance obligation goes beyond doing the work correctly. Members must maintain records of installations, use WRAS-approved products (or document equivalence), and be prepared to demonstrate compliance during audits conducted by their assessment body.
Building Regulations Approved Document G covers sanitation, hot water safety, and water efficiency. Part G1 requires cold water provision for drinking. Part G2 addresses water efficiency, setting a maximum consumption target of 125 litres per person per day for new dwellings (110 litres in areas with water stress conditions imposed by the local planning authority). Part G3 covers hot water supply and safety, with particular requirements for unvented hot water storage systems.
Unvented hot water systems over 15 litres capacity (or 500mm diameter) are notifiable work under the Building Regulations. The installer must either be a member of a Competent Person Scheme (such as APHC, CIPHE, or SNIPEF) and self-certify, or the work must be inspected by Building Control. The installer must hold an appropriate qualification, such as a Level 3 Unvented Hot Water Systems certificate (G3). The completed installation requires a commissioning certificate recording temperature settings, pressure relief valve operation, expansion vessel charge pressure, and safety device test results.
Approved Document H covers drainage and waste disposal. Part H1 sets requirements for foul water drainage, including gradients, pipe sizing, access points, and connection to public sewers. Part H2 addresses wastewater treatment systems and cesspools. For plumbers working on drainage, the documentation requirements include pipe run details, gradient calculations, air admittance valve positions, and Building Control notifications for connections to the public sewer.
The Approved Code of Practice L8 (Legionnaires' Disease: The Control of Legionella Bacteria in Water Systems) and its technical guidance HSG274 apply to all premises with water systems. Under the Health and Safety at Work Act 1974, duty holders (landlords, employers, building owners) must assess the risk of exposure to legionella and implement control measures.
Plumbers are increasingly asked to conduct or contribute to legionella risk assessments, particularly in domestic rental properties, care homes, dental surgeries, and small commercial premises. A competent legionella risk assessment records the water system schematic, identifies potential risk factors (dead legs, low-use outlets, stored water temperatures, system materials), and recommends control measures.
The ongoing monitoring requirements include monthly temperature checks (hot water at outlets above 50 degrees Celsius within one minute of running, cold water below 20 degrees Celsius within two minutes), quarterly checks of sentinel outlets, and annual reviews of the written risk assessment. All temperature readings and remedial actions must be recorded and retained for at least five years.
For a plumber servicing 50 rental properties, that is 600 monthly temperature readings per year, plus quarterly sentinel checks, plus annual assessment reviews. Without a structured record-keeping system, it becomes unmanageable very quickly.
The paperwork burden on a working plumber is substantial and fragmented across multiple regulatory frameworks:
Most plumbers keep some of this in lever arch files, some in the van, some in email inboxes, and some nowhere at all. The problem is not that plumbers do not know what records to keep. It is that no single system exists to capture, store, and retrieve all of it in one place.
Water companies have enforcement powers under the Water Industry Act 1991 and the Water Supply (Water Fittings) Regulations. They can inspect premises, require remedial work, and prosecute for non-compliance. In practice, enforcement is reactive: water companies investigate after contamination events, backflow incidents, or complaints. But when they do investigate, the first thing they ask for is documentation.
Local authority Building Control departments check Part G and Part H compliance for notifiable work that is not self-certified through a Competent Person Scheme. If the plumber is not registered with an approved scheme and has not notified Building Control, the installation is technically unlawful, regardless of its quality. This creates problems at the point of property sale, when conveyancing solicitors request Building Regulations completion certificates.
For WaterSafe members, the assessment body conducts periodic audits that include reviewing a sample of installation records, checking product compliance documentation, and verifying that notifiable work has been properly reported. Members who cannot produce records face remedial action or removal from the scheme.
Job management software for plumbers handles scheduling, quoting, invoicing, and customer records. Some offer basic job sheet templates. But none provide structured compliance documentation that maps to the actual regulatory requirements: Water Supply Regulations notification tracking, Part G commissioning certificates, legionella assessment templates with ongoing monitoring schedules, WRAS product compliance logging, and testing records with calibration traceability.
The result is that most plumbers are technically compliant in their work but non-compliant in their documentation. The work meets the standard. The records do not prove it. That gap is a liability risk, a barrier to winning commercial contracts, and an inspection failure waiting to happen.
Slatewick is building compliance management tools for plumbing businesses. Water regulation documentation, Part G certificates, legionella monitoring, WRAS product tracking, and installation records. All in one place.
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