• This list is not exhaustive, and is limited to companies having a Web page.
• Companies not listed are invited to submit their URL.
• The list is only for information and does not represent any endorsement or guarantee whatsoever of the quality, reliability and performances of the equipment manafactured by the companies listed.

RA VI (Europe)

• ABB Kent Messtechnik GmbH - Germany
  
• Armfield Limited - UK
  
• BIRAL - UK
  
• British Water - UK
  
• CAE - Italy
  
• Delta-T Devices - UK
  
• Eijkelkamp - Netherlands
  
• ELE International - UK
  
• HIP Hydrological Information Providers - Germany
  
• Hope Hydrology - Netherlands
  
• HÖRMANN GmbH - Germany
  
• Hydro Scientific Ltd - UK
  
• Hydro-Logic Ltd - UK
  
• Institute of Freshwater Ecology - UK (now CEH)
  
• Institute of Hydrology - UK (now CEH)
  
• Intelisys Ltd - UK
  
• Integrated Hydro Systems (IHS) - UK
  
• L.M Technical Services Ltd. - UK
  
• Logotronic Ltd. - Austria
  
• Nortek AS - Norway
  
• Quantum Hydrometrie GmbH - Germany
  
• RS Hydro Flow Measurement - UK
  
• SEBA Hydrometrie GmbH - Germany
  
• SIAP Bologna - Italy
  
• Skye Instruments Ltd - UK
  
• TECMES Instrumentos Especiales S.R.L. - Spain
  
• Vaisala - Finland
  
• Valeport Ltd. - UK
  
• Van Essen Instruments - Netherlands
  

RA V (South-West Pacific)

• UNIDATA - Australia
  
• NIWA Instrument Systems - New Zealand
  

RA IV (North and Central America)

• Advance Measurements and Controls Inc. (AM&C) - USA
  
• AMC Inc. -USA
  
• American Sigma Inc. - USA
  
• Edutech Technologies Corp. - Canada
  
• Environmental Sensors Inc. (ESI) - USA
  
• Gurley Precision Instruments - USA
  
• Hach Company - USA
  
• Hydrolab Corporation - USA
  
• In-Situ Inc. - USA
  
• Instrumentation Northwest Inc. - USA
  
• MESA Systems Co. - USA
  
• Rickly Hydrological Company - USA
  
• Scientific Instruments Inc. - USA
  
• Soilmoisture - USA
  
• TROXLER Inc. - USA
  

RA III (South America)

RA II (Asia)

RA I (Africa)