Out of sight may be out of mind—but don’t let that apply to your water tank! Keeping your tank fit for purpose is a health issue, as well as a property maintenance matter. The Department of Health recommends a programme of regular, preventive maintenance to keep your tank water supply clean. Here is some of their advice.

How often should you clean the tank?
By law, all water tanks should be cleaned out at least every six years, but sooner if there is significant sludge build-up. Dust, bird droppings and vegetation can be washed into your tank each time it rains. Contaminants tend to settle in the sediment at the bottom of the tank. Avoid refilling tanks with a low water level and high sediment since the resultant stirring up of contaminants can make the water unsafe to drink. Grasp the opportunity of a low water level to clean out the tank. Washing the tank should include sterilisation and checking thoroughly for cracks, which unaddressed can lead to expensive leaks. Tree roots are a frequent cause of tank wall cracks.

How can you ensure the water is clean?
That starts with the water catchment area, the roof, which should be cleaned and painted periodically. Trim overhanging trees to reduce chances of leaves entering your tank. Use wire “pineapples” on the down pipes to block leaves and twigs and clean them regularly to get rid of clogged debris. Also, use fine wire mesh to screen overflows or vents to the tank in order to keep out insects and frogs. Ensure that tank lids fit securely.

Can you use bleach to disinfect tank water?
Yes. The Department of Health recommends using 4 ounces of household bleach per 1,000 gallons of water. The formula for calculating the volume of water is (in feet): length x width x depth of water x 6.25 = number of imperial gallons. However, this method provides disinfection for only a short time—even a few days, depending on levels of contamination and rainfall. Filtration or UV light systems are more effective. The government recommends a combination of disinfection methods: for example, chlorination every two months and a filtration or UV device in the kitchen to treat water used for drinking or food preparation.

Can I get my water tested?
Environmental Health provides a water-testing service. There are two types of testing, bacterial or chemical, depending on the concern. For more information on booking a test and how to interpret the results, call Environmental Health at 278-5333.

What should I do if the water appears clean, but smells foul?
This scenario occurs with a depletion of oxygen in the water, leading to stagnation. First, apply bleach, as recommended above. Then aerate the water. This can be achieved by setting a garden hose on fine spray and directing it onto the surface of the tank water for a few hours.

What should I do to prepare for a hurricane?
Block all the gutters leading into your tank in advance of a storm to prevent saltwater from contaminating your supply. To address minor salt contamination, pipe in some freshwater to dilute the contents of the tank. You should also block the gutters when the roof is being cleaned and repainted. If roof paint gets into your tank, making the water cloudy in appearance, the tank should be emptied and cleaned. Once the roof painting has been completed, wait until after the first rain to unblock the gutters.

Can I use well water to top up my tank?
No, the government warns that well water is only suitable for toilet and laundry use.