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KUKG3 Unvented Water Heater Testing & Certification

Independent, UKAS-accredited testing and certification for unvented water heaters to BS EN 12897, supporting compliance with UK Building Regulation G3

Get certified, get compliant, get ahead. KUKG3 delivers a comprehensive service for testing of unvented water heaters to BS EN 12897 in order to meet Building Regulation G3.

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What is KUKG3

Understanding KUKG3 Testing and Certification

KUKG3 is Kiwa Watertec’s certification  for unvented water heaters, designed to help manufacturers demonstrate compliance with UK Building Regulation G3—a legal requirement for marketing and installing these products in the UK.

We offer two levels of conformity:

  • Level 3 - Product testing and certification
  • Level 1+ - Product testing, certification, and annual surveillance

Our in-house testing covers:

  • Mechanical and safety performance to BS EN 12897
  • Pressure and temperature resistance
  • Overpressure protection and operational safety

Why Choose Kiwa Watertec

Trusted by Manufacturers Worldwide

Technical Competence

ISO/IEC 17025 accredited testing

Specialist Expertise

Dedicated scheme for unvented water heaters (KUKG3)

Rapid Turnaround

Fast, reliable testing in-house or at your site

Expert Support

Technical guidance and account management

Flexible Solutions

Combined testing for other water product standards (e.g., KUKreg4, BS 6920)

Industry Recognition

Trusted by specifiers, distributors and regulatory authorities

Our Testing Process

How KUKG3 Works

    Product Review

    Initial product review and technical file assessment

    Accredited Testing

    Laboratory testing to BS EN 12897 in our ISO/IEC 17025 accredited facilities or on site manufacturing site testing can be offered

    Certification Decision

    Certification decision by Kiwa Watertec

    Certification Granted

    Issuance of KUKG3 certificate and directory listing

    Ongoing Assurance

    Optional annual surveillance for Level 1+ certification

Business Benefits

Why KUKG3 Certification Matters

Compliance:

Meet UK Building Regulation G3 requirements

Market Access:

Legally market and install unvented water heaters in the UK

Speed:

Faster certification decisions with in-house testing

Trust:

Certification backed by Kiwa’s global reputation

Efficiency:

Combine with other Kiwa schemes to reduce time and cost

Recognition & Visibility:

Achieve a sought-after certification mark and online listing

Cost Control:

Reduce overall costs and maximise your budget
Who We Work With

Supporting the Water Heating Industry

• Unvented water heater manufacturers

• Plumbing and heating system suppliers

• Distributors and importers of water heaters

• Specifiers and compliance consultants

• International manufacturers entering the UK market

Standards & Regulations We Work To

Our KUKG3 testing and certification services are delivered in line with the most recognised safety and regulatory frameworks:

UK Building Regulation G3

The legal requirement for unvented water heaters in the UK, ensuring safety and compliance.

BS EN 12897

The core safety and performance standard for unvented water heaters.

BS 6920

For materials in contact with drinking water—see BS 6920 Testing for details.

Frequently Asked Questions

Q: Is KUKG3 testing UKAS-accredited, and where is the testing carried out?

A: Yes. All testing is conducted and controlled within Kiwa Watertec’s laboratories, which are ISO/IEC 17025 accredited by UKAS and RVA. 

Q: What types of products can be certified?

A: Unvented water heaters designed for the UK market, including both production and prototype models.

Q: Is KUKG3 recognised internationally?

A: KUKG3 is recognised by UK authorities and widely accepted by specifiers and distributors.

Q: Can I combine KUKG3 with other Kiwa certifications?

A: Yes. We offer bundled testing for KUKreg4, BS 6920, and other Kiwa schemes to save time and cost.

Q: How quickly can I get certified?

A: Our streamlined process enables fast turnaround, with direct access to our in-house testing and certification team.

Directory Listings

Search KUKG3 Certified Products

Simplify Product selection and compliance checks with Kiwa's Directory of approved Unvented Water Heaters.

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Watertec Services

Water Product Evaluation & Consultancy

Accelerate product development with expert design evaluation and pre-compliance testing for sanitary and plumbing products. Trusted by manufacturers, engineers, and suppliers to meet UK and European water standards.

Contact

Pressure Tested. Market Ready. Get KUKG3 Approved.

Partner with Kiwa Watertec to ensure your unvented water heaters meet the highest standards for safety and compliance.

Request a Quote Today