Water is an essential nutrient that impacts virtually all physiological functions. Water comprises 65-78% of the body composition of a bird depending on age. Factors including temperature, relative humidity, diet composition and rate of body weight gain influence water intake. Good water quality is vital to efficient broiler production. Measurements of water quality include pH, mineral levels and the degree of microbial contamination. It is essential that water consumption increase over time. If water consumption decreases at any point, bird health, environment and/or managerial techniques should be re-assessed. Although broilers are tolerant of some minerals in excess, (calcium and sodium, for example), they are very sensitive to the presence of others. Iron and manganese tend to give water a bitter taste that may decrease consumption. In addition, these minerals support the growth of bacteria. If iron is a concern, filtration systems and chlorination are effective controls. It is advisable to filter the water supply using a filter with a mesh of 40-50 microns. The filter needs to be checked and cleaned at least weekly. Calcium and magnesium in the water are measured by hardness. These minerals in combination can form scale or deposits that will compromise the effectiveness of a drinker system. This is specially true of closed systems. Water softeners can be incorporated into a system to mitigate calcium and magnesium effects. However, sodium levels should be assessed before a salt-based product is used. Broiler performance can be impeded by as little as 10 ppm nitrates. Unfortunately, there are currently no cost effective options for removal. Water should be tested for nitrates because elevated levels may indicate sewage or fertilizer contamination. Microbial Contamination Chronic poor performance may indicate contaminated water and requires prompt testing. When testing water, evaluating the total coliform bacterial count is important, as high levels can cause disease. Assessing the total bacteria through a plate count will reflect the effectiveness of the water sanitation program. Microbial contamination can be introduced from the source of water forward. If an effective water sanitation program is not in place, proliferation of bacteria will readily occur. The water should be tested always when you see noticeable change in color, odor or taste, flooding has occurred near the well, person or animal becomes sick from waterborne disease, maintenance on water supply system, persistently poor performance or loss of pressure in water system. Water Sanitation and System Cleanout A regular water sanitation and water line cleaning program can provide protection against microbial contamination and the build-up of slimy bio-films in water lines. While bio-films may not be a source of problem to birds, once established in water lines, bio-films provide a place for more detrimental bacteria and viruses to hide from disinfectants and also act as a food source for harmful bacteria. Products which contain hydrogen peroxide have proven to be outstanding for the removal of bio-films in water lines. Biofilms have influence on natural contaminants like iron and sulfur, as well as vitamins, electrolytes, organic acids, vaccines and stabilizers, antibiotics and probiotics. Flushing All modern poultry watering systems need to be flushed, best practiced on a daily basis to remove bio film, but as a minimum three times per week. High pressure flushing requires having adequate volume and pressure. One to two bars (14-28 psi) of water pressure will create the velocity and turbulence in the pipe work to remove bio film. The open drinker system also must be flushed. In warm/hot climates it might be necessary to flush more than once a day to cool the water temperature. There are automatic flushing systems that make the flushing job easier, saving the grower time and ensuring the water flushing happens. Oxidation-Reduction Potential (ORP) Another important factor is the ORP value of the water. ORP stands for oxidation-reduction potential and it simply refers to the property of sanitizers such as chlorine to be a strong oxidizer. A strong oxidizer literally burns up viruses, bacteria and other organic material present, leaving water microbiologically safe. An ORP value in the range of 650 mV (Milli volts) or greater indicates good quality water. The lower the value, such as 250 mV, indicates a heavy organic load that will most likely overwhelm the ability of chlorine to properly disinfect the water. The ORP meter can be a useful tool for identifying and maintaining adequate chlorine supplies without overusing chlorine. Warning: Swimming pool chlorine test kits do not distinguish between free and bound chlorine. A heavy organic load would result in a greater percentage of bound chlorine resulting in a poor sanitizer even though a test kit might indicate chlorine levels of 4-6 ppm. Chlorine is most effective when used in water with a pH of 6.0 to 7.0. This pH level results in a greater percentage of active hypochlorous ions that are a strong sanitizer. Inorganic acids such as sodium bisulfate reduce water pH without tainting the water. Free chlorine residual levels are not considered useful as sanitizers unless there is at least 85% hypochlorus acid present. Most common source of chlorine includes: Sodium hypochlorite (NaOCl, household bleach) increases water pH so it is a poor option as a water sanitizer Trichlor (trichoro-s triazinetrione), which is 90% available chlorine and is in the form of tablets which slowly release chlorine over a period of time; these actually reduce water pH so it is a good option as a water sanitizer. Chlorine gas is 100% available chlorine and is the purest form of chlorine, but it can be dangerous and is restricted in its use. pH Measurement pH is the measure of how many hydrogen ions are in solution and is measured on a scale of 1.0 to 14.0 with 7.0 being neutral. pH below 7.0 indicates an acid while numbers above 7.0 indicate an alkaline. pH above 8.0 can impact taste by causing bitterness, thus reducing water consumption. High water pH can be reduced by using inorganic acids. Organic acids can also negatively affect water consumption and so are discouraged. pH impacts water quality and the effectiveness of disinfectants such as chlorine. At a pH above 8.0, the chlorine is present mainly as choleric ions, which have very little sanitizing quality. The ideal drinking water pH for a disinfection water program is between 5 and 6.5. Total Dissolved Solids Measurement of total dissolved solids (TDS), or salinity, indicates levels of inorganic ions dissolved in water. Calcium, magnesium and sodium salts are the primary components that contribute to TDS. High levels of TDS are the most commonly found contaminants responsible for causing harmful effects in poultry production. The following table provides guidelines suggested by the National Research Council (1974) for the suitability for poultry water with different concentrations of total dissolved solids (TDS), which are the total concentration of all dissolved elements in the water. Drinking System Cleanout Between Flocks Drain drinking system and header tanks. Determine the capacity of the drinking system. Prepare the cleaning solution to the manufacturer’s recommendation. Where possible, remove header tank and scrub it clean. Introduce the solution into the water system, usually in the header tank. Make sure protective clothing and eyewear are worn when using chemicals. Turn on the tap at the end of the drinking line and let the water run through until the sanitizing solution appears, then close the end tap. Raise each drinker line. Allow the solution to circulate through the drinking system. If circulation is not possible, let the sanitizing solution stand for at least 12 hours. After draining the system, flush the system thoroughly to remove bio-film and sanitizing chemicals. Water Testing Water testing should be performed on a periodic basis but at least yearly. Samples should be collected at both the well house and at the end of a drinker line using a sterile container and analyzed at an accredited lab. When taking the water sample, it is important not to contaminate the water sample. The water supplied to the birds should be fit for human consumption. Water Sampling Technique: Sterilize the end of the tap or nipple by using an open flame for 10 seconds. Never use a chemical for this process as it may affect the sample. In the absence of an open flame, run the water for a few minutes before taking the sample.