Limited Scope Contractors

When planning a plumbing project, you may find it necessary to hire specialised approved contractors.

These approved Limited Scope Contractors include:

  • Groundworkers who work with underground water supply pipes
  • Installers of commercial catering equipment
  • Installers of chilled water appliances
  • Reduced Pressure Zone Testers

These contractors are not approved WaterSafe plumbers, but are recognised by the water company schemes: APLUSTAPSWaterMark and WIAPS to work in these areas.

They will ensure all their work complies with the Water Fittings Regulations and Byelaws.


External Service groundworkers specialise in the site management, installation, repair, or renewal of underground water supply pipes.

Catering installers

Approved catering installers have passed an assessment certifying their ability to install commercial catering equipment, such as vegetable cleaners and dishwashers.

Chilled water appliances

These contractors are called ‘Point of Use’ workers and are certified to install chilled water appliances in compliance with the Water Fittings Regulations and Byelaws.

Reduced Pressure Zone Testers

Reduced Pressure Zone Testers are trained and authorised to test Reduced Pressure Zone valves, otherwise known as RPZ valves or Type BA backflow protection devices. These devices stop water flowing in the wrong direction. By law, these devices must be tested at least once a year to ensure they are working properly to protect the water supply.

The installation, commissioning, and testing of RPZ valves should only be carried out by accredited and approved testers, in accordance with the 
Water Suppliers’ Approved Installation Method AIM-08-01.

Find Your Nearest Approved Plumber

Our Partners

WaterSafe Approved Contractors' Scheme Operators

Anglian WaterAssociation of Plumbing & Heating ContractorsCIPHESevern TrentSNIPEFThames WaterWIAPS