Water Jetting Code of Practice
The WJA Code of Practice
The Water Jetting Association is recognised for developing industry-leading guidance and standards that support the safe and effective use of water jetting across a wide range of sectors.
Previously delivered across three separate publications, the Blue Code, Red Code and Purple Code, the WJA’s guidance has now been brought together into a single, unified Code of Practice: the WJA Black Code.
The new WJA Black Code underpins everything the WJA stands for and directly informs the content of all WJA training courses, creating a more streamlined and accessible approach to industry best practice.
The Code of Practice is continuously reviewed and updated, taking account of guidance from the Health and Safety Executive (HSE), which recognises it as defining water jetting standards across the industries it covers.
Topics Covered by the Code of Practice Include:
Personal protective equipment
The water jetting team – organisation and duties
Frost precautions
Water jetting units
Hose assemblies – inspection and testing
Control valves
Safe use of water jetting equipment
Care and maintenance of water jetting equipment
Water jetting accessories, including guns and nozzles
Health risks and response to injuries
Waste disposal
Drainage law
Black Code of Practice
The WJA Black Code is the WJA’s unified Code of Practice, bringing together guidance from the former Blue, Red and Purple Codes into one streamlined industry standard for safe and effective water jetting operations.
Tasks the Black Code covers include:
Industrial cleaning
Surface preparation
Tube and pipe cleaning
Drain and sewer unblocking
Drain and sewer cleaning
Chamber cleaning
Cold water pressure washing
Steam pressure washing
Hot water pressure washing
Industrial cleaning
Surface preparation
Robotic water jetting
Surface preparation
Culvert cleaning
Gully cleaning
Chemical pressure washing
Rotary floor pressure washing
Lance pressure washing
Industries the Black Code is commonly applied in include:
Construction and structure maintenance
Oil and gas exploration and extraction
Petrochemicals processing
Drainage industry
Wastewater network industry
Highways industry
Commercial cleaning
Facilities maintenance
Farming / Agriculture
Pharmaceuticals processes
Marine maintenance
Manufacturing
Railway industry
Facilities maintenance industry
Manufacturing industry
Manufacturing / Food industry
Construction industry
Car, van and lorry cleaning
Continuous Evolution of Water Jetting Best Practice
WJA code of practice is practical, robust and detailed. It act as a clear blueprint for delivering safe, high quality water jetting services.
That is why they are trusted in the industries that rely on water jetting in all its forms to provide a measure against which water jetting activity is judged.
We published our first code of practice in 1982. After it was first given a red and then a green cover, we settled on a blue one, prompting it to be known as the WJA Blue Code.
This was followed, in 2002, by a second code of practice covering water jetting in drains and sewers. With a red cover, it became known as the Red Code.
The Purple Code for pressure washing was launched in 2024.
Their strength, from the very beginning, has been the way they are continuously improved and updated, assisted by WJA members, in line with changing practices and technological advances.
For example, in 2023, the Red Code was updated to include guidance on using a jetting gun for surface preparation.
Then, in 2025, it was updated again, to incorporate the use of robotic drain and sewer cleaning systems.
Now in 2026, the Blue Code, Red Code and Purple Code have been brought together into one unified publication: the WJA Black Code, creating a single streamlined Code of Practice for the water jetting industry.
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