Victoria experienced a major drought in 2005-2006 resulting in the Victorian water Authorities to stop flushing their mains to rid the pipes of colloidal (extremely fine silt) material as a water saving measure. The authorities recognised that this will have a detrimental effect on water filter systems and started a compensation scheme for blocked water filter cartridges earlier than normal. This resulted in a flood of claims and the scheme was stopped.
The water authorities have not returned to having a regular mains maintenance procedure to rid the mains of this material and appeared to have a react only on complaint policy. The areas where the colloidal material builds up in the mains has no real pattern with some areas not having many problems and other areas having chronic problems.
The colloidal material is usually in the 0.01 to 1 micron size and when this material has been allowed to build up in the mains something disturbs it and it comes through in the water is clouds, the water filters do exactly what they are meant to do removing it but they can only tolerate so much and can result in early cartridge blockage.
The amount of colloidal material is higher in Victoria due at first the less use of flocculants compared to other states at the treatment plants to reduce the amount in the first place and added to that poor water mains maintenance to remove build of this material.
Water mains flushing is done by connecting stand pipes to every fire hydrant in the street and running water at high volume down the gutter. We bet you haven’t seen that being done in a long time.
Colloidal material can be seen in the water as a background haze when filling a bath or something that is a larger volume of water, filling a glass the material is not usually visible and it is not there all the time.
Victorian water authorities used to come and flush the mains in an area when a complaint was received in writing, but they now appear to not even doing that any more.
Water filter buyers are lead to believe that the finer the micron a filter cartridge is the better the treatment is but this is only true in part. A carbon filter cartridge that is say 0.5 micron will have about a 0.5% better filtration comparted with a 5 micron extruded carbon block cartridge but the 0.5 micron carbon block cartridge will be more prone to blockage if the colloidal material in the water is elevated. The micron rating is more about the possible presents of cysts and not all water in Australia contains cysts with Sydney water seeming the most troubled with this due to sewerage put into the dam infeed supplies by large towns on the upstream sides.