Water: The Forgotten Nutrient in Pigs

Practical advice on water quality and requirements of pigs of different ages from Susan Dawson, veterinarian with Portec Veterinary Services in Western Australia.
calendar icon 25 March 2014
clock icon 9 minute read

Water is the most important nutrient for pigs. When we think of nutrients we often only think about pig feed: carbohydrates, fats, proteins, minerals and vitamins. However, without water, pigs will only survive for a short time. As we move into the warmer months of the year it is important to ensure that your piggery’s water system is prepared for the heat of summer.

For good growth and production, pigs require access to quality drinking water. Water plays a role in the many chemical reactions that occur in the body:

  • regulates body temperature
  • transports nutrients around the body
  • removes toxins and help with filtration
  • aids in digestion
  • lubricates and protects the body’s organs.

At birth, a piglet’s body is 80 per cent water, compared to 50 per cent in a finisher. Pigs need to maintain these levels by consuming water in their feed or by drinking water. It has been reported that for finisher pigs when ambient temperature increases from 10°C to 25°C water consumption is increased from 2.2 to 4.2 litres per day. This is a significant increase in the volume of water being consumed and therefore the water systems and drinkers need to be able to meet this demand. Table 1 provides an overview of the volume of water consumed by different classes of pigs on a daily basis.

Table 1. The daily water requirements for pigs vary according to their age
Age of pigDaily water requirements
Lactating sow 24-45
Dry sow and boar 12-15
Finisher 9-12
Grower 5-7
Weaner 3-5

There are a variety of drinker systems available that suit different production systems and classes of pigs. Sows benefit from high flow drinkers that produce at least two litres of water a minute, allowing sows to drink large volumes of water in shorter time periods. 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 two litres per minute. She will do this over several sessions. Lactating sows have a higher requirement for water because they are producing milk, which is approximately 80 per cent water. 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 a flow rate that is neither too low or too high as this will discourage the sows from drinking (see Table 2).

Table 2. Recommended flow rates for nipple drinkers pigs according to their age
Age of pigFlow rate(litres/minute)Maximum pressure (kPa)
Lactating sow 2 No limit (avoid wastage)
Dry sows and boars 1 No limit (avoid wastage)
Finisher 1 140-175
Grower 1 140-175
Weaner 0.5 85-105

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 have a reduced feed intake, will lose body condition and will produce less milk for the piglets. During warm days, ‘lazy’ sows should be encouraged to stand up and drink. It is also important to ensure that the temperature of the water coming out of the drinkers is suitable as pigs do not like to drink water that is above 20°C.

The height of drinkers is also important and should be about 50mm above the shoulder of the smallest pig in the pen. Ideally, this means that drinkers should be at about snout level or just above the backline of the pig. This is important so that all pigs have access to the drinkers. On the other hand, drinkers should not be too low to the ground to avoid breakage.

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.

Annual water test

It is recommended that you test the quality of your water annually. Knowing what is 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. The best time to test is before the break of season, when water concentrates are at their highest level. Water testing will assess the following:


Turbidity is the cloudiness of the water. It is often due to silt or clay being suspended in the water and is usually not a problem to pigs. However, water that scores greater than five nephelometric turbidity units (NTU) should have additional chemical and microbiological (bacterial) analysis.


Tinting of the water is usually due to the particles in the water. In Western Australia, this is often related to iron oxide. This is usually not a concern as other parameters give a better assessment of water quality. 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.


Odour should not be present with water. If there is an odour, it may indicate the presence of bacterial contamination or organic compounds such as sulphur. The bacterial content of water can 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)

This is a measure of the total levels of bicarbonates, chlorine, sulphate, sodium, calcium and magnesium in the water. In general, TDS below 1000 is ideal for pigs, while TDS between 1,000 and 3,000 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 3,000 to 5,000 TDS can be used cautiously but salt levels in feed should ideally be discussed with your nutritionist or feed supplier.

Water pH

This is the measure of the acidity or alkalinity of water. Most water sources will be 6.5 to 8.5. It is important to know the pH of your water in case you ever need to water medicate as pH affects the dissolvability of medications.


This is the level of calcium and magnesium in the water. It does not affect the animals but it can lead to an accumulation of scale in water delivery, treatment and cooling equipment, causing nipple drinkers and filters to block up. Very hard water measures greater than 180mg per litre and soft water is less than 60mg per litre.

Hot Pigs Need Cooling

Cooling should be done 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.

This 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 ages of pigs
Age of pigIdeal temperature
Lactating sows 18-22°
Dry sows and boars 18-24°
Finisher 22-24°
Grower 22-24°
Weaner 22-30°
Suckers 32-38°

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 place an increased demand on drinkers, increasing the likelihood of damage and breakage.
  • Make sure that all tanks that store water are secure and sealed from contamination by rodents and birds. They can be a source of bacterial contamination, or worse, a breach of your farm biosecurity. Don’t risk introducing influenza into your herd.
  • Ensure that drinker flow rates are appropriate for the age of the pigs (see Table 2). This should be checked and maintained on a weekly basis. Use a 500ml 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 600mm of soil. Pipes heat up quickly in summer and hot water will stop the pigs drinking.
  • Organise to have your water tested for pH, total dissolved solids and bacteria annually — you will need to 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 do not forget your back-up pump and generator — make sure they are ready for any emergencies.

Key points to remember

  • There should be a minimum of two drinkers per pen with a recommended one drinker per 10-15 pigs.
  • Check water flow — 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 — help pigs stay cool by using cooling or sprinkler systems.


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 develop salt toxicity.

March 2014

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