Water: the forgotten nutrient for pigs

Page last updated: Tuesday, 12 January 2021 - 4:05pm

Please note: This content may be out of date and is currently under review.

Water is the most important nutrient for pigs. We often think about nutrients as only pig feed: carbohydrates, fats, proteins, minerals and vitamins. However, water is a nutrient too, and pigs will not survive for long without adequate good quality water.

Ensure that your piggery’s water system can supply all water neeeds, especially during the heat of summer.

The importance of water for pigs

For good growth and production, pigs require continuous access to good quality drinking water. Water plays an important role in their body processes:

  • regulating body temperature
  • transporting other nutrients around the body
  • removing toxins and helps with filtration
  • aiding digestion
  • lubricating and protecting the body’s organs.

Water consumption by pigs

At birth, a piglet’s body is 80% water, compared to 50% in a finisher. Pigs need to maintain these water levels by consuming water in their feed or by drinking water. When ambient temperature increases from 10°C to 25°C, finisher pigs increase water consumption from 2.2 to 4.2 litres per day (L/day), therefore the water systems and drinkers must be able to meet this demand. Table 1 lists the volume of water consumed by different classes of pigs.

Table 1 The daily water requirements for pigs vary according to their age
Age of pig Daily water requirements L/day
Lactating sow 24 to 45
Dry sow and boar 12 to 15
Finisher 9 to 12
Grower 5 to 7
Weaner 3 to 5

Drinking systems for pigs

Choose drinker systems that suit your production system and classes of pigs. Sows benefit from high flow drinkers that produce at least 2 L of water a minute, allowing sows to drink large volumes of water in less time. A lactating sow will take 12 to 23 minutes in total to consume her daily requirement for water from a drinker with a flow rate of 2 L/minute. She will do this over several sessions.

Keep the drinking water cool. In very hot conditions, use a water cooling system. Pigs do not like to drink water that is above 20°C: hot drinking water is most likely in hot summer conditions when the pig's demand is highest.

Lactating sows have a higher requirement for water because they are producing milk, which is approximately 80% water. A sow's water consumption is particularly important in the first five days after farrowing. Sows, and therefore piglets, benefit from having easy access to water from a drinker that provides an adequate flow rate (see Table 2).

Table 2 Recommended flow rates for nipple drinkers and different classes of pigs


Flow rate Maximum pressure (kilopascals/kPa)
Lactating sow 2L/minute No limit (avoid wastage)
Dry sows and boars 1L/minute

No limit (avoid wastage)



140 to 175


140 to 175
Weaner 0.5L/minute 85 to 105

As ambient temperatures increase, sows feel the heat and newly farrowed sows can become lazy and forget or refuse to stand and drink. Sows that do not drink will reduce their feed intake, lose body condition and produce less milk for the piglets. During warm days, ‘lazy’ sows should be encouraged to stand up and drink.

Drinkers should be accessible for all pigs in the pen. As a guide, place drinkers:

  • about 50 millimetres (mm) above the shoulder of the smallest pig in the pen
  • about snout level or just above the backline of the pig
  • high enough off the ground to avoid breakage.

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Water quality – what should it be?

The source of water will often determine its quality and suitability for pigs. Scheme water, dam water or bore water all have different benefits. See water quality for livestock for more detail.

Test your water

Test the quality of dam or bore water before the break of season, when water concentrates are at their highest level. Knowing what's in your water is important in case you need to medicate your water supply. Regular testing will also alert you to any changes that occur to your water quality or suitability.

Test water for:

  • turbidity
  • colour
  • odour
  • total dissolved solids
  • water pH
  • hardness.


Turbidity is the cloudiness of water – often due to silt or clay suspended in the water, and is rarely a problem for pigs. However, water that scores greater than five nephelometric turbidity units (NTU) should have additional chemical and microbiological (bacterial) analysis.


Coloured water is usually due to particles in the water. In Western Australia, this is often iron oxide. High levels of iron in the water can reduce the effectiveness of the water soluble antibiotic apramycin. Therefore, if this is a medication you may be required to use, it may be important to test the iron concentration in the water on your farm.


Livestock water should not have an odour. An odour may indicate bacterial contamination or organic compounds such as sulphur. Bacterial contamination could be a source of disease to your herd; this is a particular risk for surface sourced water, although ground water can also contain pathogens.

Total dissolved solids (TDS) – a measure of salinity

TDS is a measure of the total levels of bicarbonates, chlorine, sulphate, sodium, calcium and magnesium in the water. In general TDS below 1000 milligrams per litre (mg/L) is ideal for pigs, while TDS between 1000 to 3000 mg/L is suitable. However, if weaners are suddenly introduced to this water it may cause a transient diarrhoea for a few days. If there is no alternate water source, water containing 3000 to 5000 mg/L TDS can be used cautiously but discuss water management with your nutritionist or feed supplier. See water quality for livestock for more detail.

Water pH

This is the measure of the acidity or alkalinity of water. Water will be safe if it is in the range 6.5 to 8.5.

Water pH affects the solubility of some medications.


This is the level of calcium and magnesium in the water. Hardness does not affect animal health but it can lead to an accumulation of scale in water delivery, treatment and cooling equipment, blocking nipple drinkers and filters. Very hard water measures greater than 180 mg/L and soft water is less than 60 mg/L.

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Hot pigs need cooling

Use a cooling system when ambient temperatures are above the optimal temperature for the pig (see Table 3). Water is an essential part of many cooling systems. Ambient temperatures above the optimal temperature range can compromise the pigs and they can quickly overheat if unable to expel their excess heat.  Pigs do not sweat and so rely on the addition of water (spray/drip cooling) and air movement (wind/fans) to allow evaporative cooling.

Cooling will only be as effective as the surface area of skin that is wetted (that is, spray cooling is more effective than drip cooling).

Table 3 Ideal ambient temperature ranges for all classes of pigs.

Class of pig

Ideal temperature °C
Lactating sows

18 to 22°

Dry sows and boars

18 to 24°


22 to 24°


22 to 24°


22 to 30°


32 to 38°

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It’s getting hot, now what?

Run through the following checklist:

  • Pre-summer maintenance of all the cooling systems on the farm – replace broken sprinklers, repair any leaks and ensure hoses are flushed of any dirt or foreign material.
  • Repair any broken drinkers and ensure that there are enough drinkers for the number of pigs per pen. Heat stressed pigs drink more, increasing the likelihood of damage and breakage.
  • Secure and seal all water tanks from contamination by rodents and birds. Rodents and birds can be a source of bacterial contamination, or worse; a breach of your farm biosecurity (don’t risk introducing influenza into your herd).
  • Set drinker flow rates appropriate for the age of the pigs (see Table 2). This should be checked and maintained on a weekly basis. Use a 500 ml container and measure the volume of water collected from a drinker in 30 seconds.
  • Clean out trough and bowl drinkers on a regular basis – at least weekly.
  • Bury any exposed water pipes under at least 600 mm of soil. Pipes heat up quickly in summer and hot water will stop the pigs drinking.
  • Test your water for pH, total dissolved solids and bacteria annually – use a special sample bottle with a preservative for bacterial culture (talk to your vet about effectively collecting suitable samples).
  • Service your water pumps and your backup pump and generator – be ready for any emergencies.

Key points to remember

  • Provide a minimum of two drinkers per pen, with a recommended one drinker per 10 to 15 pigs.
  • Check water flow regularly, as if a pig drinks less than it needs, it will also eat less and grow more slowly as a result. If a pig or group of pigs are not eating much, check that the water is on and the flow rate is within guidelines.
  • Pigs cannot sweat so use cooling or sprinkler systems to help pigs stay cool.

Last point

If you discover that the water supply has been turned off or the pigs have run out of water, talk to your vet immediately. They will assist you in treating and managing pigs that have had water deprivation or developed salt toxicity.

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Authored by Susan Dawson, Veterinarian, Portec.