Detainees should have access to a sufficient quantity of clean water at all times. Available water supply should cover the drinking water needs of inmates and staff, and also be sufficient for food preparation, personal hygiene, cleaning, watering and any other basic requirements.

Since water supply is often limited, it is essential that it be managed and distributed in an equitable and rational manner. Water supply availability can be adversely affected in situations where prisons are overcrowded.

The strict minimum physiological needs of an individual are estimated at 3─5 litres of drinking water per day (ICRC). This minimum requirement increases if warranted by the climate and the amount of daily work and physical exercise performed.

Detainees should have access to water piped directly into their cells or dormitories. Where there are no taps inside the cells and dormitories, containers such as buckets and jerry cans should be available to enable detainees to store the quantity of water required. These water-storage containers should be cleaned and disinfected regularly and carefully capped to prevent contamination. The minimum amount of water that must be available inside the cells and dormitories is 2 litres per person/day if the detainees are locked in for periods of up to 16 hours, and 3 to 5 litres per person/day if they are locked in for more than 16 hours, or if the climate is hot (ICRC).

The authorities have an obligation to meet the food needs of inmates. Failure to comply with this requirement may constitute a form of cruel, inhuman or degrading treatment, or even torture. The inclusion in national law of quality criteria for food served in prisons, including minimum nutritional value requirements, is an important protective measure for detainees. The detainee food budget should allow the implementation of these minimum requirements.

Food is a universal vital need, but eating habits are highly personal and culture-specific. The imposition of a uniform food regime has a tendency to crystallise tensions and disputes. This is most clearly reflected in the number of detainee complaints registered regarding factors such as the quantity, quality, blandness and lack of variety of the food they are served. It is important that detainees have access to an effective complaints system.

Mealtime schedules, particularly for meals served in cells, are generally adapted to security requirements and staff work schedules. In most cases this means that meals, especially at dinner time, are served much earlier than is customary in the outside world. Moreover, the time available to eat meals is often limited, especially for detainees required to attend a workshop or engage in some other compulsory activity. Meal distribution arrangements should ensure that meals are still hot for people served last. The cutlery issued to inmates, while respecting local customs and security requirements, should preferably be made of metal so that it can be easily cleaned and disinfected.

The sick, especially those with heart or diabetes problems, should receive an appropriate diet controlled by the health personnel. Balanced vegetarian menus should also be available for inmates who do not eat meat.

Menu selection must be determined together with the health personnel, including nutritionists. Good practices suggest including representatives of detainees in these discussions. The nutritional value and overall quality of meals served in prison must be evaluated and controlled by independent experts from the penitentiary administration.

Sanitary and bacteriological analysis should also be carried out regularly to prevent the outbreak of contagious diseases. Samples of all food must be kept long enough to perform analysis if contamination is suspected.

Persons arriving at an institution should be able to receive a meal even outside established meal service hours. During transfers basic meals must be provided to ensure that detainees have food and drink while traveling.

Ensuring food supply, preparation and meal distribution, together with food stock management and control, are central tasks of all prison administrations.

The state of the kitchen, its location, cleanliness, size, infrastructure, and the number of kitchen staff, are elements that generally reflect the overall conditions of a prison. The kitchen location is important for various reasons: it should be sufficiently close to the food storage area and at an appropriate distance from the latrines. Waste water and smoke emanating from the kitchen must be evacuated properly without inconveniencing the inmates or prison staff. Ventilation should be adequate to ensure that kitchen staff and detainees are not exposed to toxic fumes. Natural light in the kitchen helps prevent the infestation of insects such as cockroaches. If the kitchen is located outside the prison, special care should be taken to ensure that the food is transported and distributed in the most hygienic conditions possible.

Water for cooking and drinking should be clean and available in sufficient quantity. It is estimated that a minimum of one litre of water is required to prepare a meal for each single inmate (ICRC). At least another two litres of water per inmate are required to rinse the food, wash the dishes and clean the kitchen floor (ICRC).

Food storage areas should be kept clean and in good condition, and be protected against moisture, insects and rodents.

Food distributed by the authorities must be of sufficient quantity and quality, and detainees should not have to rely on their families or on the prison commissary (prison shop) for food sustenance. In some cases, food packages provided by families are prohibited, or only certain products are allowed. Related directives must be clear and figure in regulations known to the detainees and their families.

While recognising that self-preparation of meals can help to preserve a sense of autonomy, the responsibility for feeding inmates properly nevertheless lies with the authorities. A balance can sometimes be observed in small prisons wherein detainees are given food products and are allowed to prepare their own meals in the kitchen.

Food products sold in the prison shop should not be more expensive than those available outside prison. Detainees often refuse meals distributed by the institution and prepare their own meals in their cells with products from the prison shop or received from their families, allowing them to eat more to their personal preferences. This tends to indicate that the served meals lack quality and variety, but also implies that indigent detainees cannot afford this alternative. Finally, meals prepared in cells often use hotplates linked to the electrical circuit via multiple irregular connections, increasing the risk of fire.

Like all products that circulate in prisons, food is considered a commodity to be traded. When the food served is not sufficient and/or is substituted by food products obtained from outside or from the prison shop, this phenomenon tends to increase. Detainees may be compelled to find alternatives to be sure to get their daily portion of food, which helps to reinforce the unequal treatment between detainees and consolidate systems based on privilege and corruption.

The delegation of food distribution to inmates who hold informal power within the prison, without effective control by the authorities, endangers the fair distribution of food and increases the risk of abuse and violence.

The deprivation and restriction of food and water are prohibited in all circumstances, including as a form of disciplinary action. Persons sanctioned and subjected to a disciplinary measure should receive the same meals as other detainees; food should not be used as a form of punishment. Sanctions that consist of isolating and placing a detainee on a "bread and water" regime should therefore be prohibited.

In some contexts, detainees who are sanctioned, notably for throwing away food or assaulting prison guards, are subjected to a deliberately bland and repetitive diet, sometimes in the form of porridge or meatloaf ("Nutraloaf") served throughout the disciplinary period. Even when the nutritional value of such food is found to comply with acceptable standards, its appearance, blandness and taste repel detainees who may therefore not eat sufficiently. This humiliating practice should be prohibited.

When food catering services are contracted out to a private company, the food distributed to detainees should not be of inferior quality or served in smaller quantities. Menus must be validated by the medical service and the prison administration. Inspections of sanitation services should be performed at the same frequency as in establishments where prison meals are managed by public services.

When the prison shop management is outsourced to a private company, product prices should not be higher than in other institutions, and the products on offer should be similar .The prison administration must monitor the quality and prices of products sold in the shop, to ensure that detainees are not penalized by its privatisation. The risk of this occurring is further increased in cases where both the food catering service and the shop are the responsibility of the same company. The complaints system must function in a similar way to those in public administration institutions.

Detainees from ethnic, indigenous and religious minority groups must, to the extent possible, receive meals that correspond to their customs and beliefs. Inmates who wish to follow a specific diet (e.g., Kosher, Halal) for reasons related to their religion should be able to do.

The authorities should ensure that detainees can observe fasting periods (e.g., Ramadan, Lent), in conformity with the requirements of their religion or beliefs, and make the necessary arrangements, either by serving a snack instead of a lunchtime meal ─ that may be deferred until the evening ─ and/or by increasing the quantity of the evening meal. Such fasts should not be imposed on the entire prison population, and inmates who wish to interrupt a fast should be able to do so at any time.

Given that juvenile detainees are still growing, it is particularly important that they receive a diet tailored to their specific needs, of adequate quality and quantity, and served at normal meal hours. Their diet must, to the extent possible, fulfil the requirements of their religion and their culture.

Pregnant or breastfeeding inmates should receive an adequate food diet high in protein content and rich in fruits and vegetables. They must also have access to free counselling by qualified health personnel. Inmates who wish to breastfeed should not be discouraged from doing so, unless they are advised otherwise on medical grounds. Inmates who have recently given birth, but whose child is not with them in prison, also have specific nutritional needs that must be taken into account by the authorities.