Assessment and cleaning of water lines in poultry houses 

Read More to learn best practices for taking water samples, testing and innovative ways to clean biofilm and protect your water lines.

Water quality affects poultry growth, efficiency, and livability and is influenced by microbial level, pH, mineral content, hardness, and organic matter load. Together, these factors can build resistant structures to disinfectants called biofilm inside the water lines which subsequently suppress the birds immune systems, leading to subclinical diseases. 

What are biofilms?

Biofilms are complex communities of organic materials including bacteria, algae, fungi, and slime mold attached to inorganic materials. The enclosed water system in poultry houses is prone to biofilm formation, especially during the first weeks of the rearing when the barn temperature is high. High temperature and low water pressure favor biofilm formation in drinker lines. The growth rate and composition of microorganisms involved in the biofilm structure are different from their free-living counterparts, making biofilm bacteria more resistant to disinfectants. Biofilms are different in every farm depending on water characteristics, barn management, and equipment age. 

Figure 1. Formation of biofilm inside the pipe wall (

Taking water samples

To test your water, make sure to take water samples from different locations, including the water source and the end of the waterlines. In addition to drip samples from the nipples, it is important to take swab samples in different areas of a drinker system including standpipes, inside nipple drinkers, water hoses and regulators. Figures 2 and 3 show the procedure for taking drip and swab samples from a waterline. Regulators should be investigated for the presence of biofilms and bugs regularly. That is why cleaning the waterline per se is not enough, it is important to know what is going on in the regulators as well.

Figure 2. Triggering nipple drinkers using a sterile stick to take water drip sample into a sterile bag for lab analysis (Austin et al., 2017)
Figure 3. a) cleaning the tweezers b) removing the sponge to take swab sample c) inserting the sponge inside the waterline d) taking a swab sample from the waterline (Maharajan and Watkins, 2016)

Water tests
There are two options to test your water: on-farm and lab tests. On-farm tests include color, taste, odor, turbidity (suspended solids in the water), ORP (Oxidation-Reduction Potential), pH, and chlorine. Lab tests include microbiological and mineral tests. ORP is measured by an ORP meter and is a measure of a substance’s ability to either oxidize or reduce another substance. A positive ORP represents the presence of an oxidizing agent, but a negative ORP indicates that the substance is a reducing agent. The acceptable ORP reading for poultry water, to be most effective for disinfectants, is greater than 650 mV with a reading between 700 to 750 mV being most desirable. If you encounter a lower ORP (e.g. 250 mV) for a water sample, it represents a heavy organic load or the presence of reducing agents such as ferrous iron (Fe2+), manganese (Mn2+), bisulfide (HS-), and sulfite. Under these conditions, the water needs to be treated to reduce the mineral load (e.g. using a water softener tank) and increase the efficiency of the water sanitation program. Do not forget to monitor water pH as the most effective pH range for water sanitation is between 5.5 to 7. Water minerals can also affect the efficacy of water sanitizers. The most important minerals that need to be determined by the lab test include calcium, magnesium, iron, sulfide, manganese, sodium, chloride, sulfates, nitrates, and carbonates. When it comes to the microbiological test, it is important to test the water for total plate counts (TPC) of aerobic bacteria, which should be less than 1000 CFU (coliform forming unit) per ml of water. If the result is ≥ 10,000 CFU/ml, thorough water cleaning between flock and daily water sanitation during the rearing is highly recommended.

How to disrupt and clean biofilm?
There are several methods to overcome the biofilm issue in a poultry barn. Remember that the most effective method will be different for every farm, based on the water attributes. The following is a common 3-step method:
Add an acidifier to the water to bring the pH to 4 and let it stand for 8 to 24 hours; it can dissolve the mineral complexes in the biofilm and water lines. The potential acids are acidified copper sulfate, sodium bisulfate, and the combination of peracetic acid with hydrogen peroxide.
Add hydrogen peroxide in a final concentration of 0.3 to 8% and let it stand for 12 to 72 hours to disrupt the organic component of the biofilm.
Add a disinfectant to kill the remaining microorganisms.
During each step, walk the waterline and trigger the nipples with a clean broom to make sure that the whole system is getting the treatment. Flush the water lines with high-pressure water between each step for 5 minutes or 1 minute per 100 feet (~ 30 meters) of the waterline. Notice that peroxide produces gas when it contacts the biofilm, so make sure to open the system to prevent bursting the waterline.

What should I do if the cleaning process did not work?
If you are still facing the biofilm issue after your sanitation program, consider sending swab samples from inside the waterline to the lab for testing biofilm sensitivity against disinfectants. The test is done by recreating the biofilm in the lab and exposing it to the potential disinfectants that are being used on the farms.
Finally, never base major decisions on a single test. Repeating the test for a single sample is strongly recommended. Remember to read the instructions on the label and waterline manufacture guidelines carefully before using any chemicals.

About the author(s)

Research Associate at Poultry Innovation Partnership | + posts