There are researches about drinking water quality and corrosion, and the water quality influence on the cast iron pipe corrosion in K. Grushkevica`s work “Water quality effect on corrosion of cast iron pipes”. The problems of drinking water industry, which can provide distribution net corrosion, are described in theoretical part. Factors, which can affect corrosion. Methods of water aggressiveness determination. And the new researches about the influence of water composition for the internal corrosion. Some corrosion control alternates. There are theoretical calculations about the optimal water quality for Riga city in the investigation part. Described problems and the possible solutions.