The peculiarity of the wastewater produced in Polish dairies stems from the frequency and specific technology of cottage cheese production. The aim of this study was to determine the water consumption and the quantity and quality of wastewater and sewage sludge discharged from Polish dairies based on the size of the plant and the production profile of the plant to characterize the wastewater treatment plants (WWTPs). Data were collected from eighteen dairies. Most of them have their own WWTP. Water consumption ranged from 1.5 litres (L) of water per litre of milk processed to 3.71 L/L. The specific volume of wastewater ranged from 1.18 to 5.78 L per L of milk processed. The raw wastewater concentrations were comparable to those of dairy wastewater in other European countries. Despite the disposal of domestic wastewater in WWTPs, the results of the sanitary examinations of the sludge showed it was suitable for agricultural purposes. Its heavy metal also made it applicable on agricultural land. The ratio of the sludge to raw milk processing was between 0.137 and 7.927 kg of sludge per 100 L of milk processed. The amount of sludge produced per pollutant (BOD) load removed ranged from 0.404 to 18.895 kg/kg BODre