07.Does it work?
How can you be sure these filters do what they say, without proof? One thing to look for is certification. The NSF International provides a range of certifications for products that involve initial and periodic testing:
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NSF 42 covers aesthetic effects such as chlorine, taste, odour and particles.
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NSF 53 covers health effects such as cysts (giardia, cryptosporidium), a range of organic chemicals (such as THM and pesticides) and heavy metals.
The Australian standard AS/NZS4348 covers a wide range of contaminants, such as taste, odour and microbiological and chemical impurities. There are also standards for water softeners (cation exchangers: NSF 44), reverse-osmosis (NSF 58) and distillation (NSF 62) systems.
Your own supply?
If you’re not connected to town water, but use rain or bore water, it’s important to protect your supply from contamination — particularly with bore water — and inspect it regularly.
For example, an animal carcass close to your bore can be a serious health threat, and herbicides or fertilisers may over time leach into your water supply. A dirty roof, peeling paint or bird droppings can affect the quality of collected rain water. Many water authorities or your local health department have brochures on what to look for, and how to maintain a storage tank.
Have your water supply tested regularly; contact your local or state health department. It may check the water body you’re drawing from as part of its own monitoring program, or it can test your water — in many cases free of charge if you have a health concern. It’ll also be able to advise you on how to rectify a problem. As a last resort you may want to consider buying a suitable water filter.