The report addresses the watering of pigs, focusing on those with a soup feeding system and taking into account the different stages of rearing (post-weaning and fattening piglets, pregnant and lactating sows, etc). The experts stressed the importance of the economic issue with regard to the watering of pigs on the farm, but this economic analysis was outside the scope of the expertise. The expertise focused on the production of liquid manure in pig farming in connection with watering systems, but without analyzing the environmental side of its management. The supply of sufficient quantities of water is essential for the maintenance of homeostasis and the survival of the individual. Only permanent access to drinking water allows the physiological needs of pigs to be met flexibly and individually at all times. It also enables the animal to cope with risky situations, for example, when it is hot or when it is suffering from disorders (illness, intoxication, behaviour, etc.). Moreover, permanent access to water can contribute to a state of satiation when the animal is subjected to food rationing. Permanent access to water, together with regular checks on the quantities taken, can be a warning and prevention sign of the appearance of health and welfare problems. In the case of liquid feed without the presence of a supplementary drinking trough, most of the water needs are covered for most animals. However, this type of feed does not allow permanent access to water and therefore does not allow animals to drink systematically as soon as they are thirsty. Water can be provided in the trough, but it must guarantee the permanent presence of drinking water. To ensure adequate watering with troughs, it is necessary to ensure that their design, positioning and operation guarantee optimal access regardless of the physiological stage of the animals. In the absence of manipulable materials in the pens, the drinking trough may be the target of redirected behaviour, linked to frustrated investigative behaviour (cf. Anses opinion 2013-SA-018020). Such use diverts the function of the water trough as a drinking system and may result in restricted access to water for some pigs despite a permanent supply. The introduction of water troughs in soup feeding systems may lead to an increase in the amount of water in the manure produced. However, solutions to this problem include reducing the dilution rate of the soup where technically feasible in the farm (e.g. reducing "wastage" by optimising the design and flow rate of drinkers, covering slurry pits, etc.). The experts also recommend promoting the acquisition of technical references (water flows, number of pigs per trough...) on complementary watering. At the same time, an awareness programme for farmers should be developed on the importance of watering in terms of animal health and welfare. This programme should be accompanied by technical recommendations and accompanying measures to facilitate the introduction of watering systems.