This post is designed to answer the question of what is the difference is between water filters. Hopefully, after reading this you will understand the differences and ensure you are receiving the right filtration system for your house or premises.

Firstly a definition of a water filter provided by Wikipedia…”A water filter removes impurities by lowering contamination of water using a fine physical barrier, a chemical process, or a biological process. Filters cleanse water to different extents for purposes such as providing agricultural irrigation, accessible drinking water, public and private aquariums, and the safe use of ponds.”

The following is a picture of a water filter housing and water filter cartridges. The cartridge is placed inside the housing to operate. The two together are commonly referred to as a “water filter”. In this post we will refer to them as a filter housing, water filter (housing and cartridge together) and a filter cartridge.

Example of a filter housing

Example of a filter cartridge

We already know from the above text what we can use them for. To explain all the hundreds of cartridges available will have you leaving this post about now. But to summaries there are 2 main types which we are concerned with.

  • Carbon filters that filter out the most toxins, and leave intact the mineral content of the water.
  • Sediment filters are used to filter out sand and sediment particles from the water.

Courtesy of Osmonics

The Filter Spectrum

So we can understand the size (in microns) of the openings (passageways) in the filter cartridges the following will give you an idea of what type of contaminant a cartridge will filter out for a given micron size.

You will see on the left-hand side Micrometers (Log Scale). Run across this line to the number 1.0. Under this and everything to the right are all the contaminants that will be filtered out with a 1-micron filter cartridge. This is about as small a micron rating we use in household water filtration. Usually, 5 microns is about the minimum for whole-house systems. Interesting to note that 1 micron isn’t even halfway across this chart going from right to left.

Look at the table and ask yourself what are you trying to remove from the water in the 1 to 5 micron size? The only ones I can identify that I would like removed are the cyst Cryptosporidium and bacteria. But these can be removed by disinfection. Like ultra violet light. (UV).

The Differences

So why don’t we go any lower than 1 micron? It’s all got to do with water pressure. It stands to reason that we would require much more water pressure to push water through a 1-micron hole than a 5-micron hole. If you used a hose to water your garden, you’d be very disappointed if you installed a filter system only to see pressure in your hose drop by over 50%.

There is only 1 reason why a retailer would want to sell you a 1 micron filter and it has to do with their UV system after the filters.

So now you have a basic idea in the difference between filter cartridges. You can search the internet to see what cartridges are available to treat certain contaminants. However not all are available in Australia, nor are they cost-effective to import on a small scale. Fortunately, we have located some local niche suppliers who deal with some of the more exotic examples of water contaminants.

So what about filter housings? There are two different sizes with 2 separate diameters generally sold to residential customers.

20″ x 4.5″ diameter – 1″ inlet and outlet
10″ x 4.5″ diameter – 1″ inlet and outlet
20″ x 2.5″ diameter – 3/4″ inlet and outlet
10″ x 2.5″ diameter – 1/4″, 1/2″, 3/4″ inlet and outlet

The difference in the filters is obviously their physical size and inlet and outlet sizing. For the water filter to work the water must pass through the cartridges inside the housing. So, if the cartridge has a greater surface area it stands to reason the water can pass through the cartridge at a greater rate. A 20″x 4.5″ water filter will pass water through the system at a greater capacity than a 10″ x 4.5″ given the same cartridge micron rating, inlet pressure and inlet and outlet size.

You Don’t Really Get What You Pay For

There is a huge difference when it comes to quality, wholesale cost and approvals/certifications of housings and cartridges. To give you an idea, a 20″ x 4.5″ “Big Blue” filter housing from China can be bought wholesale for around $11.00. This is not certified or approved by any authority but is sold in Australia for around $100. The same housing from Pentair in the US, fully NSF approved costs around $80.00 wholesale. And the good retailer has to sell for the same price to compete. The same applies for filter cartridges.

Ensure You Get The Right Filtration System

If you’re looking to obtain the right filtration system for your house or premises without guessing if it will work or not, call Bundaberg Water. We will ensure your entire system is designed to suit either your cost and lifestyle, or the contaminants you are wanting to eliminate. We will ensure the system is designed around your existing pump and pipe network to keep pressures as close to that which you now have.

And we guarantee the system will do what it is designed to do. Visit our Water Filtration page to find out more.

20″ x 4.5″ Big Blue Housing