Mask Group 9@2x

Cat 5 Tanks

Cat 5 Water Storage Tanks Constructed from GRP


Cat 5 Tanks (Category 5 Water Storage Tanks), also known as Type AB Airgap Break Tanks (Category 5 Backflow Prevention)

Nicholson Plastics are a water storage & regulations experts, we provide a full range of water storage solutions that provide backflow protection for Fluid Category 5 risks.

Category 5 risks are fluids that pose a serious health risk due to the concentration of pathogenic organisms or extremely toxic or radioactive elements present with them including any fluid which contains; faecal material or other human waste: butchery or other animal waste: or pathogens from any other source.


Uses for Cat 5 tanks:

  • Urinals
  • Laboratories
  • Drain cleaning plants
  • Industrial cisterns and bin
  • Chemical cleaners/contractors
  • Butchery and meat trades
  • Bedpan washers
  • Hospital dialysis machines
  • Vegetable washing
  • Laboratories
  • Dish washing machines in healthcare premises
Water Supply (Water Fittings) Regulations 1999 in England and Wales and Scottish Water Byelaws state the installation of cold water storage tanks, connected to the public water supply must comply with the UK water fitting regulations. In order to meet these requirements Category 5 Break Tanks must be used.

AB Airgap & Overflow

A non-mechanical backflow prevention arrangement of water fittings complying with Type AA, except that the air gap is the vertical distance from the lowest point of the discharge orifice which discharges into the receptacle, to the critical water level of the rectangular weir overflow. WRAS Type AB – Air gap

Read Guide to the UK Water Supply Regulations

Why work with us for your Water Storage Needs?

Over 50 years’ industry experience

Projects completed in the last 24 months

Nicholson Plastics is a UK GRP Cold Water Storage Tank Manufacturer with a proven track record in the supply of water tanks to all industry sectors throughout the UK. We have an expert team on hand with over 50 Years' industry experience. Our team works hard to provide exceptional industry lead times from quotes, site visits, order processing, and delivery. We are a British Standard approved company with full certification through BSI/ISO9001 including WRAS approved certified products for potable drinking water.

  • Over 50 years of technical knowledge.
  • Quality assurance at a local level.
  • UK customer support teams, backup, replacement service & advice.
  • Supporting local and sustaining UK manufacturing.
  • Regional sales representatives for site visits, emergency water requirements, and project advice.


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Our Accreditations

At Nicholson’s, we pride ourselves in manufacturing and installing GRP water storage solutions of the highest quality throughout the UK. To see our certifications - Click here.


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bsi member cert
Certified ISO company
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chas accredited contractor
safe contractor approved