It is difficult to establish the exact degree of the importance of water to man. It is certain, however, that without water there would be no life of any kind on the earth and that, without water readily available in adequate quantity and free of pathogenic organisms, man’s progress is tremendously hindered. From a public health point of view, there is no question that the aim should be to supply quality drinking water to every family in the barangay. Access to safe water can be achieved by protecting the main water sources, cleaning the water reservoirs and by teaching water disinfection methods in the household levels. The barangay is supplied by two protected and developed spring. Water from these two spring lines is supplying the three main water tanks which then supply all the households in the barangay. At this time, it was noted that there were two points of weakness in the supply of drinking water. First, is the contaminated water from the tanks and second, is the possible contamination of the pipes that deliver the water from the tanks and tubod. This is supported by water bacteriological analysis done from the main water sources, water tanks and household samples. The problem in the quality of drinking water in the barangay cannot be addressed by single intervention hence, the team used a variety of approaches which includes water disinfection promotion and water tank cleaning.

Prior to cleaning and disinfecting of the water tank, the residents were informed that there will be no water supply for approximately 36 hours. With the help of the barangay’s water monitoring team, the announcement was made two days before the actual tank cleaning and another reminder one day before the actual tank cleaning. The tanks were cleaned and disinfected following the WHO guidelines and standards.

Step 1- Cleaning the tank
a)      Draining/emptying the tank: The remaining water in the tank was drained out by opening the outlet valve.
b)      Cleaning/scrubbing all internal surfaces: An odorless antibacterial liquid detergent provided by the Department of Science and Technology (DOST) and stiff brush were used to clean all internal surfaces of the tank. The outlet valve was left open whilst cleaning.
c)      Washing all internal surfaces to remove all traces of detergent: The tank was continuously flushed until there are no longer traces of detergent that can be seen in the tank.
Step 2- Disinfecting the tank
            The total volume of the tank was computed to know how much chlorine is needed in disinfecting the tank. The following formula was used:
Length x width x depth of water x 1000 = number of liters

Tank 1
1.5 m x 1.5 m x 1.5 m x 1000
3375 L
Tank 2
2 m x 2 m x 2.5 m x 1000
10,000 L
Tank 3
2 m x 2 m x 2 m x 1000
8,000 L
                   Table 1. Tank measurement and its volume capacity

a)      The tank was filled with clean water up to ¼ level only. In estimating the ¼ level of the tank, a stick with graded markers was used to indicate the water level. The clean water was from the Tank III since it is the only tank that passed the microbiological examination for water. In cleaning the Tank III, water was drained out and retained up to ¼ level only.
b)      A concentrated chlorine solution was then prepared to disinfect the tank. High test hypochlorite (HTH) granules or powder was used as this normally contains 50-70% chlorine. A bucket was filled with 20 liters of clean water and a 50g of HTH was added to the water and stirred until dissolved.
c)      The solution was poured slowly into the tank, mixing it while pouring using the same stick with graded markers. 10 liters of the chlorine solution was added to the water in the tank for every cubic meter of tank volume (1 cubic meter=1000 liters) and then the tank was filled up to a full capacity of water.

33.7 L
84.6 g
100 L
250 g
80 L
200 g
Table 2. Computed amount of water and chlorine granules needed for tank cleaning
d)     The tank was then closed and the chlorine was left in the tank for 24 hours to ensure that the tank is fully disinfected.
e)      After 24 hours, the tank was emptied completely and the disinfecting water was disposed properly. The waste liquid was collected in a temporary pond and was mixed with sand. The mixed sand was transported to a land fill area 1-2 kms away from the tanks and households for disposal.
Step 3 – Chlorine testing
a)      The tank was refilled with clean water and was allowed to stand for 30 minutes.
b)      The residual chlorine left in the tank was tested by water analysis. A water sample from the disinfected tank was collected and was sent to Zamboanga del Norte Medical Center for physico-chemical and bacteriological testing.
Simple interventions were introduced to the residents but these interventions made a huge impact to their lives helping them realize the importance of having a safe drinking water.





We are nine (9) passionate, dedicated and goal-oriented medical students with diverse personalities who came together to achieve one goal. We are an all-scholar group with the intention to serve God and His people. For the next four years in the medical school, we have a vision to help the people in the community to become self-reliant. Through community participation and cooperation, everything can be achieved. We choose to serve the community. We choose to serve Venus. | web counter hits


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