How to Improve Poultry Drinking Water Quality with Acidification

The correct acidification of drinking water with an enhanced acidifier will benefit performance and enhance gut health.

Water has often been called “the forgotten nutrient” and not without reason. In many cases, it is assumed that water will be available for the chickens to drink, and that it requires little or no maintenance to keep an adequate supply. Often, little thought goes into whether or not the water is suitable for the birds to drink.

A chicken will drink anywhere between 1.8 to 3 times the amount of food it eats, dependent on the strain, housing conditions and temperature. An inadequate quantity of water will therefore directly reduce feed intake, negatively affecting performance. The removal of water from a flock in lay will halt egg production very rapidly, and when combined with the removal of feed as well, will induce moulting.

Water vaccination

Water is also the medium of choice for administering live vaccines to chickens. This method is applied whenever possible as it has a markedly reduced stress factor for the chickens, as well as a lower cost of administration. Vaccination is always best carried out in the morning when the birds have had a natural period of water deprivation overnight, and will be less stressed compared to inducing thirst through a physical deprivation later in the day. The early morning is also the natural time for the birds to eat after the night, so they will eat and drink more readily at this time.

Water quality

Water is one of many vectors that can transport pathogens such as bacteria, viruses or protozoa into the poultry house. Some diseases, such as infectious coryza and Haemophilus paragallinarum can also spread through the drinker system, especially if it is a non-nipple system. Therefore, water hygiene must be considered an integral part of any biosecurity programme. Part of this will include regular water quality checks, including measuring both dissolved salts and, more importantly, bacterial contamination. To be considered acceptable, water should contain less than 100 CFU/ml of coliforms and less than 100,000 CFU/ml of total bacteria (Table 1). There should be no Salmonella contamination in the drinking water. Where water does not comply with this standard, steps should be taken as quickly as possible to rectify the areas that are failing.

Five tips for ensuring good water quality

Tip 1 - Apply water sanitization

In order to maintain water quality, it is advisable to use some form of water sanitization. The most common method uses chlorine, dosed either into a holding tank or directly through a dosing machine into the water in the house. Town water is usually chlorinated to a level of 3 ppm at the point of entry into the house. However, by the time water reaches the last drinker in the house, this may have reduced significantly depending on cleanliness and any organic matter in the pipes. It may be advisable to increase the level of chlorination on farms to offset this possible loss in efficacy.

Tip 2 - Test water quality regularly

Water should be tested frequently in order to ensure that its quality is stable, and that dosing equipment is functioning correctly. To do this, water should be collected from the farthest point of entry into the house, the last drinker. The degree of water sanitation, or lack of it, varies considerably across the globe, from sophisticated systems in some developed countries to no sanitation at all in several developing countries.

Tip 3 - Check for biofilm

In many parts of the world the levels of hardness, dissolved solids in the water, are quite high, which increases the pH to the upper end of acceptable levels. These salts, especially calcium or magnesium salts, can form deposits in the water pipes that can ultimately reduce water flow. Additionally, they can also encourage the build-up of biofilm in the pipes by providing attachment sites for bacteria to lodge. Biofilm is a living colony of microorganisms comprising bacteria, algae, fungi and even protozoa. This living colony is protected by an accumulation of filamentous proteins excreted by some of the bacteria, which over time can further reduce the flow of water through the pipes. The different types of pathogens found in biofilms are quite extensive as shown in Table 2.

Table 1. Parameters of acceptable water quality
Table 1. Parameters of acceptable water quality
Table 2. Some of the pathogens isolated from biofilms
Table 2. Some of the pathogens isolated from biofilms

Tip 4 - Thoroughly clean the water system between flocks

Thorough cleaning of the water system between flocks is strongly recommended, using products that can remove both the biofilm and any limescale present. This often requires a two-strategy approach with a product such as hydrogen peroxide to remove the biofilm, and an acid product to remove the limescale in hard water areas.

The build-up of biofilm can be reduced during production by regularly flushing out water lines. This should be done under water pressure of between 1.5 and 3.0 bars (20 – 40 PSI). Flushing of water lines should be carried out at least once per week, and more often in hot climates to ensure good results. This will reduce the risk of parts of the biofilm breaking loose in the water pipes and causing an obstruction in the drinker valves, or releasing undesired pathogens into the water supply. Any remaining residues of water treatment should be removed immediately after the treatment by flushing the system.

Hard water increases the pH of the water. Today, there is some debate over the recommended acidity/alkalinity of water, with current views tending towards reducing the pH to the lower levels, between pH 4 and pH 5. This is in order to create a pathogen-static environment, thereby limiting their development in the water lines.

Tip 5 - Aim for the optimal pH level

When chicks hatch, they have an immature gut, and the production of acids in the proventriculus and gizzard is reduced in the first seven to fourteen days. Experimental work showed that the pH level of the proventriculus ranged from 5.2 at day one to 3.5 at day 15, with a linear reduction between hatching and day ten of age. Similarly, the pH in the gizzard dropped from 3.5 to 3.3 between day one and day ten, then stabilizing at a pH of 3.3 at day 15 (Rynsburger, 2009).

Care needs to be taken when acidifying water to ensure that the correct amount of acids are applied to reach the desired pH of 4.5 of the drinking water. Failure to do this can result in either over-acidification of the water, which can hinder water intake and damage the equipment, or an under-acidification, which can then provide an energy source to the bacteria residing in the water line.

Figure 1. Effect of pH on the proportion of hypochlorous acid when chlorinating water
Figure 1. Effect of pH on the proportion of hypochlorous acid when chlorinating water
Figure 2. Effect of pH on pathogenic bacterial development
Figure 2. Effect of pH on pathogenic bacterial development

Four benefits of water acidification

Many companies are employing chlorination as a way to sanitize water, either by having access to town water or adding chlorine to water on the farm. However, the efficacy of chlorination depends on the formation of hypochlorous acid, which has stronger antimicrobial activities than the hypochloride ion. The level of hypochlorous acid produced will be dependent on the pH of the incoming water (Figure 1).

Benefit 1 - Acidification prevents bacteria from reproducing

Most pathogenic bacteria are Gram-negative and as such are sensitive to acidic environments, which have a bacteriostatic effect. When a chicken is drinking twice the quantity it eats, the acids in the drinking water can have a beneficial effect in the crop, reducing pathogenic development.

Figure 2 shows that below pH 5, many pathogens are stable and not increasing. However, pathogenic bacteria will start rapidly multiplying once the pH goes above pH 5, peaking at pH 7 – 8.  While Gram-negative bacteria are sensitive to acids, they also have an in-built protection against water-soluble agents in the lipopolysaccharide outer membrane of their cell wall. This limits the passage of antimicrobial agents into the cell wall, thereby giving them a degree of protection.

However, adding a permeabilizing agent to the acidifier, for instance Biotronic® Top Liquid, can increase the direct antimicrobial activity in the drinking water and in the upper intestinal tract. This is due to the disruption of the outer lipopolysaccharide layer by the permeabilizing complex, enabling a greater uptake of acids into the cell, enhancing the antimicrobial effect.

Benefit 2 - Acidification does not affect in-feed probiotics (direct-fed microbials)

Many of the probiotics rapidly gaining popularity in poultry production are Gram-positive. They are either lactobacilliales, lactic acid producing bacteria, or sporulated bacillus bacteria, which are much less sensitive to acidic environments. As a result, acidifying drinking water has no impact on probiotic products in feed.

If probiotics are administered in the drinking water via a dosing machine, and only one dosing machine is available, water acidification should be stopped during the time the probiotics are administered, and then recommenced once they have been consumed. A similar approach should be taken when vaccinating through the water supply. If the vaccine is applied directly into the header tank, this will have no detrimental impact on the probiotics, but the water should not be acidified when vaccinating.

Benefit 3 - Acidification helps keep limescale and biofilm at bay

Acidification of the drinking water can also reduce the build-up of limescale in the drinker lines, which in turn will also reduce the levels of biofilm due to a lower level of bacterial contamination. This will not negate the need to clean the drinker lines between flocks, but it may help prevent blockages or leaking drinkers caused when biofilm breaks loose within the pipelines, affecting drinker function.

Benefit 4 - Acidification can help early protein digestion

Acidity also plays a major factor in the transformation of pepsinogen to pepsin, which is essential for protein digestion. Lysine digestibility in day-old broilers is 78%, but rises to above 89% by 14 days of age (Batal and Parsons, 2002). Therefore, acidification of the water may benefit early protein digestion by slightly reducing the buffering of the feed passing from the crop to the proventriculus.

Chick starter diets are one of the most buffered diets the animal will receive, with the exception of layers and breeders in production, due to the calcium and protein content. This may explain increasing successes in acidifying drinking water in the early stages of production.

Biotronic® Top liquid

The correct acidification of drinking water with an enhanced acidifier, such as Biotronic® Top liquid from BIOMIN, will benefit performance and enhance gut health through microbial modulation, reducing the pathogen challenge in the intestine and increasing protein digestion. Adding Biotronic® Top liquid goes further to inhibit bacterial growth and prevent limescale and biofilm build up, while also boosting early protein digestion without interfering with in-feed probiotics.


Water is an essential part of optimal flock performance. However, since water is able to transport pathogens into the poultry house, its quality and management is extremely important. Sanitization, regular testing, checking for biofilm in pipes and thoroughly cleaning lines between flocks can all help to ensure water quality is as high as possible. Adding an enhanced acidifier product will deliver additional performance benefits as well as reducing the level of bacteria in the water.


Batal, A.B. and Parsons, C.M. 2002. Effects of age on nutrient digestibility in chicks fed different diets. Poultry Science, v.81. 400-407.

ISA Management Guide. 2014. Management Guide: Alternative production systems. ISA: A Hendrix Genetics Company. [On-line]. Available at: [Accessed 16.09.18].

Rynsburger, J.M. 2009. Physiological and nutritional factors affecting protein digestion in broiler chickens. Master Thesis. University of Saskatchewan. [On-line]. Available at [Accessed 22 May 2018].

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