The paper presents the results of studies of the structure and changes in construction costs, as well as sales profitability, of water supply and sewage networks constructed from 1961-1970 in Warsaw and Lodz, Poland. The level of sale prices and building costs of water supply and sewage networks is determined by hydrogeological conditions, cost of removal of other installations, technical and other solutions used by contractors, obstacles met during construction, and the level of estimated prices for construction. The price level is planned by the state in Poland. The included data show that the water supply lines consisted of 46% cast iron, and 54% asbestos cement, with 42.1% of 100-mm diam, 41.5% of 150-mm diam, and 16.4% of 200-mm diam; for sewage networks 30% was 200-mm diam, 19.4% was 250-mm diam, 31.4% was 300-mm diam, and 19.2% was 400-mm diam.