With so much attention paid to feed ingredients, average daily gain and feed efficiency, water’s virtues as an important nutrient are too often overlooked. Yet water is needed in the greatest amount of any nutrient used to produce pork, and with hot summer days ahead, its importance grows even more.

Unless pig performance challenges surface, water doesn’t usually come to mind even though it may be the culprit. “Water is the most essential nutrient needed for life,” says Tom Guthrie, Extension swine specialist, Michigan State University. “It is often misunderstood and mismanaged compared to other nutrients.”

Water performs several critical functions in pigs. It regulates temperature, carries nutrients into body tissues and removes metabolic waste from the system. Thus, if your pigs’ water intake is inadequate it results in production shortfalls.

Two common problems that arise from inadequate water consumption are reduced feed intake in growing pigs and increased incidence of urinary tract infections in sows. It also can decrease milk production in lactating sows.

How Much is Needed?

Pigs’ water requirements vary due to many factors. High ambient temperatures will increase water requirements, and other factors include high salt intake and lactation.

Water requirements have a close relationship to feed intake and body weight. “Under normal conditions, swine will consume 2 to 5 quarts of water per pound of dry feed or 7 to 20 quarts of water per 100 pounds of body weight daily,” according to the 2007 Swine Nutrition Guide, Kansas State University. It points out as “a rule of thumb, self-fed hogs will consume 1.5 to two times as much water as feed.”

Lactating sows require about 5 to 6 gallons of water per day for adequate milk production. Nursing pigs past 3 weeks of age need access to water in addition to sows’ milk.

According to the National Pork Board’s Swine Care Handbook, nursery, grower and finisher pigs require about 0.3 gallons of water per pound of feed consumed. However, ambient temperature and the herd’s health status influence that amount.

Posting daily water consumption charts in a barn can prompt workers to keep an eye on water use. Since sick pigs drink less water, a reduction in consumption can provide an early signal of illness in a herd.


What Influences Consumption?

Drinker flow rate is an important factor to watch. As a room or facility increases in size, pay close attention to the amount of water actually being delivered all the way down the line. Make checking waterers a priority for all barn personnel. Check nipple flow rates often and always before placing animals in a pen.

Inadequate flow rates will make pigs stand at a drinker for long periods which reduces other pigs’ access to water and prevents some from receiving adequate amounts. To check flow rates, Guthrie measures the time it takes a drinker to fill 1 cup of water. For example:

  • Piglet — 60 seconds
  • Nursery — 30 seconds
  • Grower — 20 seconds
  • Finisher — 15 seconds
  • Sow — 10 seconds

Nipple height, plugged nipples and flow rate can each affect water intake as well as waste.

Avoid watering systems that allow the water to get too warm. Drinkable water is usually between 40° F and 65° F. In high ambient temperatures, pigs will drink up to twice the amount of cool water (50° F) than warm water (80° F).

Make sure all pigs in a pen have easy access to the water supply. “Allow one nipple drinker for every 10 to15 pigs,” Guthrie says. “For groups larger than 10 in the nursery pen and more than 15 to 20 in a finishing group, at least two waterers are recommended,” he adds. While little data exist for cup drinker systems, a general rule is no more than 20 pigs per cup or bowl.

Check Supply Line Capacity

Make sure the actual water supply lines provide adequate flow.  As swine facilities grow in size, capacity of water supply lines also must increase.

Guthrie points to an example developed by Mike Brumm, Brumm Swine Consultancy. The example shows water delivery requirement for a 1,000-head finishing facility with 20 pens per side. With two nipple drinkers per pen, each requiring a 4-cup-per-minute flow, the water-delivery requirement when all nipples are activated at the same time is 10 gallons per minute for each side of the barn.

If the supply line doesn’t provide that flow, there’s a risk that one or more drinkers has reduced flow, or perhaps no flow, when a pig is attempting to drink.

Checking water delivery devices is tedious work and requires a time commitment by you and your staff. However, making the necessary adjustments in flow rates, drinker height and delivery capacity can prevent production shortfalls which can result when requirements for this essential nutrient are not met.

Editor’s note: An article in the August issue of Pork magazine will address water quality and conservation. 

Water Pressure Impacts Flow

Water pressure and line capacity are critical issues that can impact your pigs’ water consumption.

“Undersized water lines are a big issue in swine barns, especially when we go up to 2,400 pigs in a room,” says Mike Brumm, Brumm Swine Consultancy, Mankato, Minn. “Water pressure reducers, typical on many barns, are often set to lower pressure by 50 percent from the incoming line. This reduction reduces flow to 71 percent of incoming capacity.”

Brumm says that references and manufacturers indicate that Schedule-40 PVC should be sized based on 4-feet-per-second velocity. At 5-feet-per-second velocity, you will require Schedule-80 PVC due to increased pressure.

Brumm provides the following calculations of water delivery capacities for various inside-diameter PVC pipes based on 4-feet-per-second velocity:

  • 0.375 inch = 1.25 gallons per minute
  • 0.5 inch = 2.5 gallons per minute
  • 0.625 inch = 3.8 gallons per minute
  • 0.75 inch = 5.5 gallons per minute
  • 1.0 inch = 9.8 gallons per minute
  • 1.25 inches = 15 gallons per minute
  • 1.5 inches = 22 gallons per minute

Watch for Warning Signs

Keep an eye out for signs that pigs are not getting adequate water. These include reduced feed intake and pigs clustered around a drinker, says Tom Guthrie, swine specialist, Michigan State University. Possible reasons for water limitations include:

  • Water supply is turned off.  It really can happen, and it’s usually due to miscommunication or simply forgetting.
  • Rusted or blocked pipes can block or slow water flow.
  • Faulty drinker devices. Check them regularly or whenever you detect one of the previous warning signs.
  • Frozen lines.
  • Inadequate water pressure.
  • Insufficient drinkers. If too many pigs are present, some of the pigs may be denied
    sufficient access.
  • Inappropriate drinker height. Adjust the height to accommodate the smallest pigs in the pen.
  • Poor water quality. Water that appears cloudy, frothy, dark or has a bad smell indicates you need to have a water laboratory test it to see if contamination exists.
  • Stray voltage. Even as little as one-half-volt stray electric charge may drop water
    consumption. If you suspect stray voltage, ask your electric supp