• A D Water Designs
  10 Blanford Road, REIGATE, Surrey, RH2 7DR
• Activated Water Technologies Ltd
  1 Hollybush Close, Buckhurst Avenue, SEVENOAKS, Kent, TN13 3XW
• Ames Crosta Investments Ltd
  Biwater House, Station Approach, DORKING, Surrey, RH4 1TZ
• Avital Water Ltd
  28 Casewick Road, LONDON, Greater London, SE27 0SY
• Blue Water Telecoms
  281 Whitehorse Lane, South Norwood, LONDON, Greater London, SE25 6UL
• Cascal Services Ltd
  Biwater House, Station Approach, DORKING, Surrey, RH4 1TZ
• Clean Water UK Ltd
  2 Burbridge Way, Tottenham, LONDON, Greater London, N17 9AJ
• Drinking Water Inspectorate
  Room M03, 55 Whitehall, LONDON, Greater London, SW1A 2EY
• Drinking Water Solutions London Ltd
  26 Broadway Parade, Crouch End, LONDON, Greater London, N8 9DE
• Essex Water Co
  342 South St, ROMFORD, Essex, RM1 2AL
• Free Hot Water Ltd
  6 Stoneleigh Park Road, Ewell, EPSOM, Surrey, KT19 0QT
• Houseman Water Hygiene Specialists Ltd
  17 Applewood Drive, LONDON, Greater London, E13 8BF
• Hunter Water Services Ltd
  Flat 2 No. 11, Queens Borough Terrace, LONDON, Greater London, W2 3TB
• Just Add Water
  291-293 Hornsey Road, LONDON, Greater London, N19 4HW
• Just Water Now
  3 Locks Yard, High Street, SEVENOAKS, Kent, TN13 1LT
• Living Water House
  519 Liverpool Road, LONDON, Greater London, N7 8NS
• Lullingstone Water Ltd
  South Wing, Lullingstone Castle, Eynsford, DARTFORD, Kent, DA4 0JA
• M+M Water Tech Services Ltd
  Scrubbs Farm, Lower Gravel Road, BROMLEY, Kent, BR2 8LL
• Marlyn Water Ltd
  41 Castleview Gardens Gantshill, ILFORD, Essex, IG1 3QB
• Sentinel Water Ltd
  Rainham House, Manor Way, RAINHAM, Essex, RM13 8RH
• Thames Water Utilities Plc
  Wick Lane Depot, Wick Lane, LONDON, Greater London, E3 2NA
• The Water Delivery Company UK Ltd
  Units 17-18, Glenville Mews, LONDON, Greater London, SW18 4NJ
• Water Science Ltd
  89 The Green Way, EPSOM, Surrey, KT18 7HY
• Water Works UK Ltd
  21 Cornwall Avenue, LONDON, Greater London, N22 7DA