Water hygiene topic

Contamination: Types & Sources — for the Blue Card assessment

Microbiological, chemical and physical contamination and where it comes from.

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To keep contamination out of the main you have to know the forms it takes and where it comes from. The assessment checks you can recognise the risks around a job.

What contamination types and sources covers in the assessment

  • Three types of contamination: microbiological (bacteria, viruses, protozoa), chemical (fuel, oil, solvents, wrong jointing compounds) and physical (soil, debris, swarf, insects)
  • The biggest microbiological danger is faecal/sewage contamination
  • Common sources: the ground and soil, foul water and sewage, dirty tools and fittings, standing water in the trench, vermin, and the operative themselves
  • Contamination gets in through open pipe ends, during jointing, from unclean fittings, and by backflow
  • Standing water in an excavation is a contamination risk and should be removed
  • Whenever work stops, open ends are capped so nothing can get into the main

Where people slip up

Leaving a pipe end open to the trench. Cap or plug open ends whenever work stops.

Only thinking of germs. Fuel, oil and the wrong jointing compound are chemical contamination too.

Forgetting you are a source. Dirty hands, tools and illness can all contaminate the water.

Test yourself on contamination types and sources

Both free mocks draw from this area — 25 questions in 30 minutes, with an explanation for every answer and a per-area breakdown at the end.

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The other areas

Why Water Hygiene Matters
Public health and the waterborne diseases that contaminated drinking water can spread.
Personal Health & Hygiene
Weil's disease, reporting illness, hand hygiene and covering cuts.
Backflow & Cross-Connection
Back-siphonage, cross-connections and the devices that prevent them.
Hygienic Site Practices
Clean tools and fittings, capping open ends and keeping the trench clean.
Materials & Approved Products
WRAS-approved materials, and the right jointing compounds and lubricants.
Disinfection & Chlorination of Mains
Swabbing, chlorination, contact time, flushing and sampling before supply.
Standpipes & Hydrants
Authorised use, backflow protection and keeping them clean.
Working on Live & Repaired Mains
Bursts and repairs, flushing, and returning a main safely to supply.
Legislation & Responsibilities
The Water Industry Act 1991, the Water Fittings Regulations and the DWI.
Read the complete Blue Card guide

Independent study material, not affiliated with or endorsed by EUSR or Energy & Utility Skills. Always check the official EUSR website for the current scheme and card requirements.