Water Meter, Flanged Woltman Water Meter, Single Jet Type Water Meter-Water Meter Supplier Water meters are instruments for measuring water flow. Most of them are cumulative flow measurement of water. They are generally divided into two types: volumetric water meters and speed water meters.Water Meter, Flanged Woltman Water Meter, Single Jet Type Water Meter-Water Meter Supplier Water meters are instruments for measuring water flow. Most of them are cumulative flow measurement of water. They are generally divided into two types: volumetric water meters and speed water meters.