Many people experience hard water problems. Water hardness is determined by the ratio of calcium and magnesium salts in the water. These dissolved minerals are found in soil and rock deposits that the water travels through, and cannot be removed by filtration. What this can often lead to is limescale deposits in pipes and hot water systems, which clog up and cause blockages in the plumbing. Sediment deposits can also build up over time if the hot water system is not properly maintained.
Hard water in different states
Some parts of Australia have significantly harder water supplies than others - Adelaide, for example, has more than ten times as much calcium carbonate in the water as Melbourne does. Below is a rough guide to how hard the water supplies are in different Australian cities (measured in parts-per million of calcium carbonate):
- Adelaide: 134-148
- Brisbane: 100
- Canberra: 40
- Darwin: 31
- Hobart: 5.8-34.4
- Melbourne: 10-26
- Perth: 29-226
- Sydney: 39.4-60.1
Bore water, a necessity in some rural communities, can also cause issues with hot water systems if not treated effectively. In addition to naturally being very hard water, bore water can also sometimes carry an undesirable odour. This is caused by the build up of anaerobic bacteria which react with the magnesium/aluminium sacrificial anode to produce hydrogen sulphide gas, the same awful smelling gas which gives rotten eggs their well-deserved reputation.
Limescale build up, if left untreated, can cause your hot water system to fail. Electric tank systems are especially vulnerable to scale crusting up on the outside of the heating element. This reduces the heat output of the element considerably, forcing the system to work much harder to heat up your water. Gas systems are also affected by this though, as the scale building up on the inner walls of the hot water tank means heat has to be applied for longer to get through.
Once you know there is a problem with limescale, it is hard to get rid of. The most reliable method is to manually remove the scale with a de-liming agent or by scraping it off. Check with your hot water technician on the best way to do this.
Preventative methods include lowering the temperature of your water heater. If it is too high, scale will build up much faster. Water softeners are often used to treat scale build up, but there is a lot of argument over which methods work most reliably and for longest, and softeners have been shown to greatly reduce the lifespan of your sacrificial anode.
Sediment is the accumulation of silt and other particles in the bottom of your tank. Harder water causes the sacrificial anode rod to disintegrate faster, and also carries a lot of small debris that winds up layering the bottom of the tank. This is dangerous in two ways. It isolates the base of the tank from the protection of the anode, and causes overheating which can melt the protective vitreous enamel coating on the inside of the tank. Both of these problems can literally cause the bottom to fall out of your tank!
The easiest way to ensure good water flow in the tank is to install a curved dip tube. That way, the sediment is flushed around every time cold water is fed into the tank and pushed out to the filters.
Treating water odour
To remove the odour from the water, some specialists recommend getting rid of the sacrificial anode. This fixes the problem, but voids the warranty on your tank and is a sure fire way to rust it out well before its time. Others suggest an aluminium anode, but the best solution is to get an alloy anode of aluminium and zinc. The zinc is important, since reports indicate the aluminium anode by itself is ineffective in treating this problem. Another option would be to get a powered anode. These don’t degrade but are much more expensive.
Health and soaps
Due to the high calcium content of hard water, it also affects how well soaps and detergents are able to work. If your water is hard, it may mean you'll need to use more soap or detergent to achieve the normal results. There are generally no significant health issues with hard water, although some studies have shown weak indications that hard water may have effects on cardiovascular health and on the incidence of eczema in children.