Is water from water tanks safe to drink?

This question is obviously very broad and needs to be qualified; it all depends on the source of water that is being stored in the water tanks as well as the type of water tanks under consideration.

Type of water tank where water is stored

The type of water tank, more specifically what the water tank is made from, may influence the safety or at least the palatability of the water that is being stored.  Steel water tanks can become rusty inside which could lead to contamination of the stored water.  Although this is not necessarily dangerous in the short term, perhaps over the long term it could be.  The taste of the water could also be unpleasant.  Water stored in cement reservoirs could be tainted, especially in the early stages after the reservoir has been newly constructed.  Good quality fibreglass water tanks are generally inert but if glass fibres are not properly sealed, perhaps these could contaminate the water and cause health problems.  In the past, asbestos water tanks were popular – these could contribute to asbestos poisoning if not properly lined on the inside.  Poor quality plastic water tanks could potentially contaminate stored water with leachates and if not lined on the inside, the water could develop a distinct ‘plastic’ taste.  Probably the best choice is a high quality polyethylene water tank made by a trusted brand name (be sure to check that there is an inert lining on the inside of the water tank to keep the water safe from leached chemicals and tasting good).

Source of water stored in the water tank

The source of the water going into the water tank and whether or not it has received any filtration/purification before entering the water is obviously very important when determining whether the water is safe to drink.  Municipal water is generally ‘safe’ although it may contain high doses of chemicals which are harmful to human health over the long term.  Borehole water from groundwater supplies is often assumed to be pure and safe to drink but it should always be regularly tested, especially in urban areas or if the borehole is near industrial activities or human waste.  Dam and river water pumped to water tanks can vary in quality and also should not be assumed to be safe to drink.  Rainwater, harvested from rooftops is usually of good quality but it may have collected contaminants from the roof and gutters.  All the above examples show that it is wise to appropriately filter and/or purify water from your water tanks before using it as drinking water.  The great thing about rooftop rainwater harvesting is that you have control of the source (it was pure before reaching your rooftop) and can appropriately filter or purify the rainwater yourself.  Other sources of water may contain unknown chemicals and heavy metals, not to mention pathogens which makes choosing a filtration system that removes all these contaminants difficult and costly.

We recommend JoJo Tanks polyethylene water tanks for storing rainwater and water from other sources.  All JoJo Tanks vertical and horizontal water tanks are made with a food-grade, FDA-approved black lining to ensure the water is kept fresher for longer and also inhibits algae growth.