Complete Guide: UK Plumbing Regulations 2025 - What Professionals Need to Know

New UK Plumbing Regulations 2025 — Summary

• Fire safety: From 2 March 2025, all new care homes in England require sprinkler systems. Guidance is within Approved Document B (GOV.UK).
• Future Homes Standard (FHS): Government plans publication during 2025 with implementation from 2026. See the consultation overview at GOV.UK.
• Part L & low-temperature systems: The 2021 uplift (in force) expects new or fully replaced wet systems to operate effectively at a max flow temperature of about 55 °C. See Approved Document L (GOV.UK).
• Building Safety Act & golden thread: Higher-risk buildings require stronger record keeping and dutyholder controls. See Golden thread guidance (GOV.UK) and the Building Safety Regulator (GOV.UK).
• NHBC Standards 2025: Apply to NHBC-registered plots starting 1 January 2025. See NHBC Standards.

Core regulations plumbers work with

Part G — Sanitation, Hot Water Safety & Water Efficiency

• Limit bath hot water to a maximum of 48 °C using appropriate TMVs.
• Meet the water efficiency target of up to 125 L/person/day (many LPAs require the 110 L option).
• Products in contact with wholesome water must satisfy Regulation 4 requirements. See: Approved Document G (GOV.UK), Water Fittings Regulations 1999 (legislation.gov.uk), WRAS Approvals.
• Unvented hot water work (G3) is notifiable unless self-certified via a Competent Person Scheme: CPS list and scopes (GOV.UK).

Part H — Drainage & Waste

Internal soil and waste, below-ground drainage, ventilation and access requirements must follow Part H. Coordinate gradients, testing and rodding access with the design and inspection plan. See Approved Document H (GOV.UK).

Part L — Conservation of Fuel & Power

• Size new or fully replaced wet heating systems to operate effectively at about 55 °C max flow temperature (or lower where feasible).
• Insulate primary CH/DHW distribution, cylinder connections and secondary returns to meet loss limits (refer to AD L tables; BS 5422 for guidance).
• Provide commissioning evidence, photographic records and the BREL report at handover.
• See Approved Document L (GOV.UK).

Fire Safety — Approved Document B (2025)

• Sprinklers are required in all new care homes in England from 2 March 2025. Coordinate early on flow, pressure, isolation and testing.
• Handover must include appropriate fire-safety information where your work affects fire performance (Regulation 38 pack).
• See Approved Document B (GOV.UK).

Building Safety Act — Higher-Risk Buildings

• Maintain accurate installation, commissioning and product records to support the golden thread of information.
• Confirm dutyholder roles and information requirements before work starts.
• See Golden thread guidance (GOV.UK) and Building Safety Regulator (GOV.UK).

Designing and installing low-temperature wet systems

1. Heat-loss and emitter sizing: Design for about 55 °C flow temperature. Document design temperatures, delta T and emitter outputs. Reference AD L (GOV.UK).
2. Pipe sizing and insulation: Keep velocities and pressure drops suited to LTHW, insulate per AD L loss limits. Photograph insulation and junctions for evidence. AD L (GOV.UK).
3. Controls and balancing: Provide effective zone and temperature control, then balance after commissioning. Evidence goes into the BREL and photo set in AD L (GOV.UK).
4. DHW safety: Verify 48 °C max at baths with TMVs, while maintaining legionella control. Reference AD G (GOV.UK).
5. Product compliance: Keep evidence that fittings in contact with drinking water meet Reg 4 requirements: Water Fittings Regulations 1999 (legislation.gov.uk), WRAS Approvals.

Documentation to hand over

Part L evidence pack

• BREL report, commissioning sheets, and clear photographic evidence of emitters, pipe insulation, cylinder connections and controls.
• See AD L (GOV.UK).

Part G pack

• Water efficiency calculation (125 L p/d or 110 L p/d where required by planning).
• TMV verification for 48 °C max at bath outlets.
• Reg 4 product list and approvals. See AD G (GOV.UK) and Water Fittings Regulations 1999.

Safety and fire pack

• Fire-stopping data sheets and any information required by Regulation 38 where your work affects fire performance.
• See AD B (GOV.UK).

Unvented systems

• G3 commissioning certificate and notification via Competent Person Scheme or Local Authority Building Control.
• See CPS guidance (GOV.UK) and AD G (GOV.UK).

NHBC plots

• Follow NHBC Standards 2025 chapters relevant to drainage and internal services. Keep inspection and test records aligned with the site’s NHBC requirements.
• See NHBC Standards.

Job-type checklists

New homes (England)

• Design emitters and pipework for about 55 °C flow. Evidence in BREL and calcs. AD L.
• Insulate primary runs, cylinder connections and returns per AD L.
• Water efficiency calc and TMV checks per AD G.
• Apply the 2025 NHBC chapters where applicable: NHBC Standards.

Retrofits or replacements

• Full replacements should be designed for about 55 °C flow, or record why it is not feasible. AD L.
• Upgrade service insulation where reasonably practicable, and keep photo evidence.

Higher-risk buildings (HRBs)

• Maintain a searchable record set for the golden thread: design, test results, water quality records, fire-stopping details, valve schedules and O&M.
• See Golden thread guidance and the Building Safety Regulator.

Care homes (new build)

• Coordinate sprinkler isolation, backflow protection and testing, plus Reg 38 handover info.
• See AD B.

Future Homes and Buildings Standards

Government plans to publish the Standards in 2025 with a transition into 2026. Expect further emphasis on low-carbon heating, controls and fabric. Design to low-temperature, heat-pump-ready specifications now to avoid redesign later. See the consultation at GOV.UK.