Water Systems - Troubleshooting common mistakes

By John Carr, DPM, PhD, Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University - This article looks at the findings of a field study undertaken to identify the problems in drinking systems and explains how enhancing the water supply can prove to be a major factor in both treatment and prevention of diseases.
calendar icon 29 September 2003
clock icon 21 minute read


Farmers are generally ignorant of the pig's requirement for water at all stages of production. Enhancing the water supply proved to be a major factor in both treatment and prevention of cystitis and pyelonephritis.1 In addition, when the water supply to lactating sows was enhanced weaning weights increased by up to 1 kg per pig at 24 day weaning, and days between weaning and breeding was reduced by up to one day, from an average of 6 days to 5 days (unpublished data). A field study was undertaken to identify the problems in drinking systems.

Materials and methods

Study principles
A record of observations of different water delivery systems on pig farms was carried out. The aim of the study was to identify the problems which result in disruption or marginalization of the water supply system. The investigation was carried out during routine herd health or specific disease/disorder investigations. On no occasion did the farmer specifically request an investigation of the water supply as a specific item. Because the study was carried out as part of the clinical examination of other problems specific detailed records of each drinker on the farm were not possible or practical, but the results are collated to provide information and form the basis of further studies.

Delivery system
The water delivery systems during the course of the studies were systematically broken down into six parts: the source, the filtration system, the method of farm storage, the water distribution around the room, the drinking appliances, and the surrounding environment.

Prevalence of problems
The prevalence of each type of water drinker error was recorded within three categories:

1 Rare: Occurred on less than 5 farms
2 Uncommon: Occurred on more than 5 farms but less than 20
3 Common: Occurred on more than 20 farms

Equipment used to examine the water supply:
Stop watch; measuring cylinder and funnel; wench to remove drinker; screwdrivers, pliers and a pocket knife to help in dismantling the drinkers; a water pressure meter; a thermometer; measuring tape; sterile 400 ml bottles; and gloves used to collect water for analysis.

Table 1
Farm locality and key used in the result table

Locality Key Symbol Number of units examined The size of breeding populations Farming systems included
North America
North Carolina NC 35 500–3500 Intensive farrow to finish. Multisite units.
Michigan Mg 3 300–650 Intensive farrow to finish. Outdoor farrow to wean.
Ontario Ca 5 500–1000 Intensive farrow to finish.
UK - North East NE 128 20–600 Intensive farrow to finish.
UK - North West NW 30 6–1000 Intensive farrow to finish. Indoor loose housing.
UK - Midlands Mid 5 100–250 Intensive farrow to finish.
UK - South West SW 10 150–950 Intensive farrow to finish.
UK - Anglia An 7 150–1000 Intensive farrow to finish. Outdoor farrow to wean.
Spain Sp 5 300–750
South East Asia
Thailand Ta 2 1000 Intensive farrow to finish.
Malaysia Ma 1 750 Intensive farrow to finish.
Kenya Ky 5 200–400 Intensive farrow to finish. Outdoor farrow to wean.

The criteria by which the water supply was examined:

  • Water quality: The water quality was checked against the Canadian Water quality guidelines for livestock.2 In the farm environment, the water had to look fresh with no smell and have no unpleasant taste.
  • Number of drinkers: A minimum of one working nipple or bite drinker for each 10 pigs.3 Other observations based on the behavior of the pigs.
  • Height: The height to a nipple and bite drinker was based either on the manufacturer's recommendations or the MidWest Service Plan,4 together with the behavior of the pigs using the drinker.
  • Flow: An assessment of the flow of water from the drinkers was based largely on personal recommendations and experience (Table 2). Other observations were based on the behavior of the pigs using the drinkers.

Table 2. Personal recommendations for water flow rates:
Pig Type Litres/min
Suckling 0.3
Weaner 0.7
30 kg grower 1
70 kg finisher 1.5
Adult 1.5-2
Lactating sow - bite drinker 1.5-2
Nose drinker in trough Min 2.5

Position of the drinker: The pig had to have easy access to the drinking appliance. The minimum distance between a drinker and an obstruction or other drinker was one pig length.

Time spent drinking: Any pig (excluding lactating sows) that needed to spend more than 10 minutes drinking per day was deemed unsatisfactory.

Stockperson's attitude towards water requirements: Fifty-seven stockpeople were asked, "what daily observation was made to indicate that there was a fault with the water supply?"


Water Source Problems
Problem Occurrance Examples/comments
Mains/Local authority
Contamination Rare Five farmers complained about water quality, three about nitrates. However, none was substantiated following chemical and bacteriological examination of the water supply.
Bore hole/Off farm storage
Contamination Rare Three examples
  1. Sitting of the bore hole only 20 meters from an unlined slurry lagoon. Two years after use the water supply smelled of manure and farm production started to become sub-optimal, characterized by poor growth rates and increased days to bacon. Investigations revealed estimated daily feed intakes had reduced progressively for nine months.
  2. Bacterial contamination: Escherichia coli results in chronic sub-optimal performance seen on 2 farms. Iron bacteria build up resulting in a blockage of drinkers and water lines. This was recorded on three farms.
  3. Algae bloom resulting in blocked drinkers and pipelines.
Silted up Common in sandy area's Sand filled in the bore hole and the water became heavily silted. This resulted in blocked drinkers and water lines throughout the system. Filters were needed within the system to remove the sand.
Salts Water from artesian wells Only 4 farms examined. The salt (NaCl) concentration was too high for human or pig consumption, if used would have lead to palatability problems and increased risk of "salt poisoning." However, the water was suitable for pressure-washing and latrines.

Filter Problems
Problem Occurrance Examples/comments
Silted up Uncommon Poor maintenance and a silted up bore hole resulted in filtration systems with persistently blocked filters. Farm staff became accustomed to the problem and tended to ignore the filter. The farms subsequently suffered with poor and irregular water pressure and flow around the farm.
Filter Removed Rare Associated with poor maintenance. The stock people removed the filters generally because they were constantly clogging up, but this resulted in increased silting of drinker filters and poor water availability to the pigs.

Farm Distribution Problems
Problem Occurrance Examples/comments
Poor water pressure Common Header tanks were not filled due to poor water pressure from the mains/bore hole supply, in particular during times of peak demand for water, i.e. when staff were pressure-washing.Over-stretched rural water supplies also contributed to farm pressure problems.
Variable water pressure over the day N/A* Water pressure varied over the day, from 14 to 60 psi, presumably in response to local water demand. Varying water pressure resulted in varying water flow from the drinkers
* Only one farm examined, insufficient detail
Lack of water Rare Whilst rare, during four farm visits it was discovered that the mains supply had failed, however, the local water authority had not contacted the farm. In one case the farm was without water for 3 days. In the final case over 200 weaned pigs demonstrated evidence of "salt poisoning."

Non-return Valve Problems
Problem Occurrance Examples/comments
Taking water straight from the mains in the UK Common In the UK it is illegal to take water straight from the mains supply. In other countries no such restrictions apply. The restrictions are in place to protect the mains supply from back flow micro bacteriological contamination
Very few seen on UK Four farms examined No problems with systems seen

Header Tank Problems
Problem Occurrance Examples/comments
Poor fitting lids Common Allowed contamination of water from bedding and vermin. Light encouraged algae growth. These contaminations resulted in disease spread (leptospirosis from rodents for example) and blocked distribution system from the algae and bedding.
No lid Common Allowed contamination of water from bedding and vermin. Light encouraged algae growth. These contaminations resulted in disease spread (leptospirosis from rodents for example) and blocked distribution systems from the algae and bedding
Presence of contamination Common Even with a properly fitting lid, on three occasions dead rats were found in the header tank. On 77 occasions the header tanks was overgrown with slime molds. Presumably the contamination was present when lid was last reapplied.
Presence of antibiotic on ball valve Rare On four occasions chlortetracycline was found on the ball valve as a green sticky mass (Tetsol™). The major concern was that some material could fall off into the water and produce residues in the meat at slaughter.The farmers had not pre-dissolved the antimicrobial in water prior to administering the antibiotic to the pigs.
Ball valve problems Rare Two occasions
  1. Outdoor farm where the ball valve in the field troughs header tank raised shut with silt moved back from trough.
  2. Ball valve stuck half shut by rubbing on side of header tank, the ball had been replaced, but was too large for the header tank.
Ball valve tied up Uncommon Seven occurrences where the ball valve was tied up, once maliciously from a disgruntled farm staff, the other six from accidental forgetfulness following water medication of the pigs. All cases resulted in "salt poisoning."
Inadequate size of header tank Common In itself this is not a problem unless
  1. The header tank was being used for water medication in which case the medication may have had to be administered an unacceptable number of times, up to 15 times a day on one farm.
  2. The water pressure in the supply system was too low, the header tank became drained and did not refill fast enough to compensate for the pigs' demand.
Poor sitting of the header tank in the room Common Header tanks were required to supply water to a very long distribution system. The longest encountered in this study was 100 meters from an 80 liter header tank. Multiple header tanks or central positioning proved to be a better system.
Height of the tank Uncommon The pressure in the distribution system is determined by the header tank height. On some farms the height of the header tank was inadequate for the distribution system.

Water-distribution Problems
Problem Occurrance Examples/comments
Reduction in Diameter Common Reduction in the internal diameter resulted in flow problems at the drinker. Three main causes were identified:
  1. Mineral sedimentation, i.e., lime resulting in progressive reduction in the internal diameter particularly in old, poorly maintained metal pipes. Alcathene pipes were less subject to this problem.
  2. Iron bacteria in the USA North Carolina were a common occurrence resulting in blockage and a reduction in internal diameter in pipe.
  3. Algae often encouraged by the use of sugar-based products, such as antimicrobials or water sweeteners.
Poor sitting Common One long distribution system with a reduction in pressure along the pipe. See header tank Problems
Insufficient diameter Common Majority of room distribution systems only used a 13 mm pipe whereas a larger 22 mm pipe would be more suitable for the distribution system.
Water made available on a timer Common In the hands of good stockpeople this did not result in problems, however, the pigs' water requirements were often ignored to fit into a daily routine. Water flow then exceeded the pigs' immediate water requirements and no water was then available for hours.The manager complained that stockpeople failed to activate water flow, particularly at weekends.
Deliberate restriction of water Uncommon In traditional systems of farming, sows immediately post-weaning were given only restricted water availability to help control mastitis. This procedure is uncommon in today's farming systems.
Circular movement in down pipe Common Where drinkers were part of the fence line, the drinkers project into the pen. When the distribution pipe revolved around its axis, the drinkers became part of and parallel to the fence line, making it very difficult for pigs to obtain water.
Water too hot Uncommon In the tropics water storage facilities were poor and the water delivered to the pigs was in excess of 30°C
Freezing Common Associated with poor lagging and sitting of pipe. Outdoor farming systems had to make provisions to water pigs when distribution system failed as pipes were laid on the surface of the ground because of the transient nature of UK outdoors pig farms.

Common Drinking Appliance Problems
Problem Occurrance Examples/comments
Inadequate flow Common Associated with:
  1. Material in the drinker, i.e., rust, sediment, pieces of straw.
  2. Wrong drinker for the system, i.e., low-pressure system with high-pressure drinkers.
  3. Wrong flow adjuster either due to an incorrect adjuster in place or poor maintenance.
  4. Ignorance about the provision of adequate water flows.
  5. Inadequate water flow to the drinker.
Drinkers too high Common This caused restrictions particularly to the smaller pigs in the pen and difficulties in activating the drinker properly, which resulted in increased water waste.To compensate for the incorrect height, concrete steps were provided resulting in leg damage and abrasions.
Drinkers too low Common Resulted in difficulties drinking, increased water waste and time necessary to obtain water requirements
Incorrect angle Common Resulted in difficulties in drinking, increased water waste and time necessary to obtain water requirements. Excessive wear on the drinkers resulted in a reduction in drinker life expectancy. Pigs using a poorly adjusted drinker can result in facial distortion resembling Atrophic Rhinitis.
Inadequate numberof drinkers Common Particularly with nipple and bite drinkers. The MAFF3 recommendations of one drinker per 10 pigs were generally ignored. The inadequate number of drinkers resulted in reduced water availability, particularly to the lower social order pigs.
Drinkers too close Common Resulted in one or more pigs dominating the drinker
Poor sitting Common Drinkers placed too close to a wall or feeder make accessibility difficult
Drinkers difficult for stock people Common Drinkers placed at the rear of the pen resulted in poor maintenance and checking by stock people
Quality of drinker Uncommon Poorly made drinkers had reduced life expectancy
Wrong drinker for age of pig Common Adult drinkers were used for piglets and vice versa. All resulted in poor drinking position, increased water waste and time necessary to obtain water requirements
Leaking drinkers Common Increased water waste but also created wet bedding/lying areas, increasing the risk of disease.
Poor maintenance Common The longest time recorded by the author where a drinker had not been removed and the pipe line flushed was 14 years and the current drinkers failed to operate correctly.
Variation in drinker type Common A variety of drinkers in the same pen and between pens in the same house. This resulted in variation in water flow and thus feed takes and growth rates between pigs housed in different pens. This error was seen on two feed trial farms.

Problems with Individual Types of Drinker
Problem Occurrance Examples/comments
Nipple Drinkers
All of the above Common Where flow was poor it was very unusual to find a nipple drinker that did not work at all. Rust was a problem around ball valve drinkers associated with poor flow.
Pressure/flow too great for the drinker design Common This created a jet of water, where the flow was so great it sprayed the next pen of pigs. The high flow rate caused difficulty in drinking. The finishing pigs were heard to be choking after attempting to drink on one farm in NC.This was particularly common with the water supply to suckling piglets.
Bite drinkers
Wrong angle of drinker Common Angle affects water availability in two ways:
  1. Wrong angle of rotation
    Resulted in two problems:
    1. Poor drinking position and increased waste and time necessary to obtain water requirements.
    2. Sows that have rings in the nose were liable to damage from the drinker. Two farms had to position bite drinkers upside down to prevent this occurring.
  2. An incorrect angle to wall resulted in increased water usage and wastage
Nose drinker
Water spray not directed into trough Common A nose drinker is intended to spray water into the trough. It is not intended to provide water to the pig directly. Where the nose drinker was incorrectly set up water sprayed out of the trough resulting in restricted water availability, increased water waste, and wet bedding.
Blocked up with bedding Common Resulted in poor water availability associated with poor maintenance and sitting.
Presence of fecal material Common The presence of fecal material was associated with poor sitting and poor maintenance.
Inadequate depth of water Common Inadequate depth of water resulted in pigs having to take more time than normal to obtain water.
Inadequate depth of trough Uncommon Inability for the trough to hold sufficient water for pigs to drink.
Variability in slope along trough Common Resulting in varying depths and localized water overflow resulting in waste associated with either poor initial design or poor maintenance.
The presence of stale feed Common Caused by pigs not eating all feed provided for them, i.e., sows in oestrus, sow removed from crate and yet feed still supplied, pig sick and not eating feed supplied, over-supply of feed. Feed in the trough resulted in contamination of system and reduced the intake of water by some sows. The feed also temporarily dammed the water line to sows down stream (three days in one farm) and when the feed became moldy this increased the risk of mycotoxicosis.
Poor cleaning of troughs Common Particularly the ends of the trough which were often contaminated with moldy waste feed which acted as a source of mycotoxins and attracted rodents and flies.Water supplies to sick pigs was particularly contaminated with moldy feed and other materials, particularly if the trough was difficult to clean. This was a serious disease risk on 5 farms with salmonellosis.
Use of troughs as wallows Common Particularly in outdoor systems with inadequate wallows and/or methods to keep sows out of the water troughs. In indoor yarding systems with a river trough system the trough was too wide on 5 farms and pigs could wallow in the trough and thus contaminate the water.The use of troughs as wallows increased the risk of leptospirosis.
Dirty float Common In systems where the water depth was regulated by a float, the maintenance of the float was generally very poor or neglected.
Holes in trough Common Particularly in farrowing houses forward combined feed/water trough. Poor maintenance and rust created holes and the water leaked out. On 10 farms holes were intentionally created to stop sows playing with water.
Wet Feed Systems
Inadequate provision for sick pigs or emergencies Common Many wet feeding systems do not have an additional water supply system.
Incorrect water/feed mix Rare Only seen on 2 farms where there were problems of growth rate and investigations into the water: meal ratio was carried out.Feed mixes are recommended to be 2.5:1 (water/feed ratio) by MAFF (1995). However, mistakes are made.
Turkey Drinkers
Lack of cleaning Common Build up of mold occurred rapidly and drinkers had to be cleaned every 2 to 3 days with a mild disinfectant (iodine for example) to keep slime molds in check.
Use with pigs greater than 25 kg Common Bigger pigs threw the drinker around and increased water wastage. Using turkey drinkers, 2 used there for too old a pig
Incorrectly positioned Common For example: in contact with the floor so that water constantly ran, resulting in water waste. In totally stalled systems this type of water spillage can be missed by the stockperson.
Surrounding environment
Stray voltage Uncommon Outdoors electric fencing came into contact with the water supply, resulting in the pigs receiving an electric shock when drinking on 6 farms.Sandy soil was difficult to earth and all metal work, including drinkers became charged.
Slippy floors Common Particularly when drinkers placed outside. Exposed floors become icy in the winter and sows, for example with locomotor difficulties, restrict their water intake rather than risk slipping on the floor. This resulted in an 'outbreak' of cystitis and pyelonephritis on one farm.
Poor positioning of other pen furniture Common Poorly placed feeders restricted access to the water supply. Large pen toys such as tires also appear to restrict access on some farms.
Other pigs Common Other pigs also restricted the water supply when they lay in front of a drinker. This was particularly important in the summer when dominant pigs wallowed in front of drinkers restricting access to lower social order pigs. This was more important if the pen was overstocked.
Summary basic maintenance
Poor or no specific cleaning / maintenance routines Common In majority of farms there was no established cleaning or maintenance program. Even routine daily checking was impossible to comply with owing to pen layout.
No cleaning between batches Common Despite claiming all-in/all-out, few farms included the water system within their cleaning protocols. In only two farms (NE, NC) the water supply was cleaned between batches. All other farms in all localities, no cleaning policy.
No water to suckling piglets. Common There was no provision for water to suckling piglets, particularly in outdoor units and in several older indoor units.
57 stock people re: water Common Stockpeople were asked "what daily observation was made to indicate that there was a fault with the water supply?" The most common answer (32 stock people) was "the pig's refuse to eat." Other answers included, "grouping around the drinker" (12), "no water from the drinker" (6), "poor water flow" (4), "pigs taking a long time drinking" (2), "dirty looking drinkers" (1).
Stock people just failing to see problems with the water supply Common There was a general belief that if there is a drinker in the pen that
  1. it would work and
  2. that irrespective of flow, the pigs would spend time to drink enough.
In the course of these studies, pigs were seen crowding around drinkers, fighting over drinkers, or just standing and drinking for over 30 minutes in front of working stock people while nobody noticed.


Water is the most important nutrient required by the pig as it has the greatest body turnover.5

The pig industry has lived with water deprivation for years, even giving acute deprivation a name 'salt poisoning' which the industry accepts as common.6 In the sow, cystitis and pyelonephritis accounted for 20% of sow deaths7; however, greater awareness of the provision of water and urination patterns of sows in the last few years has resulted in the condition becoming more uncommon. Increased awareness of the need to provide water to lactating sows has resulted in a new review of her nutritional requirements as the opportunities to increase weaning weights and enhance future reproductive performance can be achieved by optimizing lactation feed intake. This is only possible by adequate provision of water.

Unfortunately there have been few scientific studies of the water requirements of pigs and research goals have moved away from animal science. This paper clinically assesses the water supply system and identifies particular areas of concern, thus allowing the veterinarian, animal scientist, and pig producer to ensure no impairment in the availability of water.

It is an indictment of the pig industry that more attention to basic stockmanship is required as so many of the faults reported are classified as common (occurring on more than 20 farms out of the 200 farms in the study). Out of the 68 recorded problem areas, 47 were classified as common, 8 uncommon, and 13 rare. To date there has not been a farm examined where no fault in the water supply could be found. Faults in the water supply were noted throughout the water distribution system, with the majority being intra-room faults, i.e., header tank, distribution pipe, and drinker. Individual farms and localities also have their own problems, for instance in the East Riding of Yorkshire, UK, blockage of the distribution pipeline with lime deposits is very common due to hard water and the age of the distribution systems. North Carolina, on the other hand, suffered blocked filters associated with sand, rust, and iron bacteria as a major problem because farm water supplies originated from bore holes drilled in sandy soils.

Excluding the 8 farms where "salt poisoning" was present, none of the other farms examined had related any of their problems to insufficient water supplies. However, while the provision of water is not a guarantee of health, improving the water on many of these farms improved the overall herd health and reduced clinical problems on the unit. In particular, in all 20 farms examined with chronic or acute pyelonephritis, the condition disappeared after improving the water supplies.

The study revealed the following areas of particular concern:

  1. While stockpeople know water is essential for survival, they have little awareness of the water requirements of the pig and there are few sources of accurate information. Only a few companies supplying drinkers offered any advice and support with regard to number of drinkers, flow rate, and positioning. It was also disappointing that several stockpeople activated a drinker, obtained only a dribble of water and then proclaimed the drinker worked. On numerous farms (over 20%) the water supply for the piglet was better than those supplies for the sow, and yet stockpeople still insisted that the reason for the sow not eating was a disease agent rather than the lack of water.
  2. Few farms had any pro-active protocols for the cleaning, maintenance, or repair of the water supply apart from repairing/replacing drinkers when they were found not to work.
  3. During the study, when 57 stockpeople were asked,"what daily observation was made to indicate that there was a fault with the water supply?" the most common answer (32 stockpeople), was "the pig's refuse to eat" which only happens after at least 24 hours deprivation.
  4. Farm buildings have not been built with the intention of monitoring the pigs' environment.
  5. Current recommendations about water are generally vague and more detail is required to provide adequate guidance to stockpeople.


1. Carr J, Walton JR, and Done SH: 1995. Cystitis and ascending pyelonephritis in the sow. In Practice. 17:71-79.
2. Canadian Water Quality Guidelines for Livestock: 1987. Task force on water quality guidelines.
3. MAFF: 1995. Codes of recommendations for the welfare of livestock. Pigs. MAFF publications 1983. Reprinted 1995.
4. MidWest Service Plan: 1983. Swine Housing and Equipment Handbook. 4th Ed. Ames, IA: Iowa State University Press.
5. Adolph EF: 1933. Physiological Reviews. 13:336-371
6. Osweiler GD, Carson TL, Van Gelder GA, and Buck WB: 1984. Clinical and Diagnostic Veterinary Toxicology, 3rd Ed. Iowa, Kendal and Hunt.
7. Smith WJ: 1984. Sow mortality - limited survey. International Pig Veterinary Society Proceedings. Ghent. p. 368

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