Environmental pollutants, harmful bacteria, and parasites can contaminate rainwater, and drinking it can make you sick. Boiling, filtering and chemically treating rainwater can help make it safer for human consumption. Many experts say that untreated rainwater may not be safe for human consumption, even though national guidelines suggest that the risk of getting sick from drinking rainwater is low. While useful for many things, rainwater isn't as pure as you might think, so you can't assume it's safe to drink.
Rain can carry different types of pollutants into the water you collect (for example, bird droppings on the roof could end up in the barrel or water tank). Rainwater can carry bacteria, parasites, viruses and chemicals that could make you sick, and it has been linked to disease outbreaks. A properly maintained rainwater tank can provide good quality drinking water. As long as rainwater is clear, has little taste or odor, and comes from a well-maintained water collection system, it is likely to be safe and unlikely to cause illness for most users.
However, when rainwater falls from the sky, substances in the air and the earth melt into the rainwater. Fortunately, when rainwater penetrates the ground, it turns into mineral water. This water (groundwater) is relatively safe to drink. However, rainwater that falls to the ground is not only absorbed into the ground, but goes everywhere.
If it falls on waste, it becomes wastewater, as it becomes contaminated. It can also flow across the sea and into river systems. Filtering can also remove some, but not all, of the hazardous metals that have been found in many Australian water tanks. Showering, flushing toilets, and watering gardens with rainwater help conserve the city's water supply.
Alternatively, the tank inlet should be disconnected so that the first rain runoff after a dry season is not collected. Collecting, storing and using rainwater, called rainwater harvesting, can be an effective way of conserving and reusing local water. If the roof catchment and tank are well maintained and the water looks, smells and tastes clean, the risk of getting sick is low. In addition, it gives rise to all water problems, such as lack of water, flooding, water pollution and excessive use of energy.
Clean the roof or wait until after the next rain before reconnecting the drinking water tank to the roof. If so, the rain in a coal mining area will be “Coal Rain”, and the rain in the industrial complex should be “Chemical Rain”. To maintain a safe water supply after the initial dose, 1 gram of calcium hypochlorite or 4 milliliters of sodium hypochlorite per 1000 liters should be added to the rainwater tank and allowed to stand for a minimum of two hours. So filter water to remove metals, but if your roof has received a lot of ash from nearby fires, it might be worth taking a water test to make sure poisonous metals don't get through.
This “first flush” can be used for washing, watering plants, or other non-drinking uses.