How to Select a Water Filter Part 2 of 10: Sediment Filters

In part one of this ten part series we created some broad water categories. Treated and untreated, potable and non-potable. Before proceeding any further you should categorize your water. If you recall, treated only deals with disinfection for microorganisms, and potability pertains to every type of contaminants and whether or not they exceed EPA regulations. So, now that you’ve categorized your water, you should identify your specific water issue. For this we identified four more categories; sediment, taste & odor, dangerous contaminants, and the nth degree. The rest of this article will pertain to sediment filters.

Let’s start with simple sediment issues. There are many ways that sediment appears, and each circumstance is unique. So, where should you start? At the fundamental level you need a whole house filter system. Why whole house? Because sediment impacts everything. It’s more than a drinking water issue, though you probably don’t want to drink it, but it collects in hot water heaters hurting their efficiency, it wears on components in your washing machine, and stops you from getting truly clean clothes etc… It’s a whole house problem, so you need a whole house sediment filter.

Before I give you an example of a whole house sediment filter, we should address system size. Unfortunately, for reasons beyond understanding, many water filter manufacturers label their small water filter housings as “whole house” water filter housings, but they really are not. There are five industry standard water filter housing sizes that utilize industry standard size cartridges. They are (based on filter cartridge size) 5″ x 2.5″, 10″ x 2.5″, 20″ x 2.5″, 10″ x 4.5″, and 20″ x 4.5″ (see our previous article for more details). Way too many homeowners are troubled by a water filter housing that is much too small. A larger housing is superior in every way. Flow rates will be higher, pressure loss will be lower, time between filter changes will be longer, and water filter cost will be less per square inch (kind of like buying the bigger bottle of Mayo). For whole house situations do not use the 5″ x 2.5″ or the 10″ x 2.5″ water filters, they are designed for much smaller applications like campers or drinking water systems intended to supply a small drinking water faucet. With that said, the following water filter housings are the correct size for whole house applications: 20″ x 2.5″, 10″ x 4.5″, and 20″ x 4.5″.

Now we need to discuss water filter cartridges. This is where your previous categorizing work pays off. If you have untreated water you definitely need to avoid cellulose media. Cellulose is commonly found in pleated cartridges, but a few manufacturers also make pressed cellulose cartridges. Cellulose comes from plants and is therefore food for any microorganism fortunate enough to find your filter, where they will live, grow, multiply and possibly cause dangerous threats to your health. Untreated water needs a bacteriostatic filter media. Bacteriostatic means that microorganisms are unable to live and multiply on the filter. A common bacteriostatic media is polypropylene, though polyester is to. There are two typical types of polypropylene water filters; string wound and blown. The string wound water filters appear, as the name indicates, to be a spool of tightly wound string. The blown come from the same polypropylene, but the poly is heated and melted then blown out of a gun and spun onto a cartridge, not unlike cotton candy. They have identical performance, and are great for sediment removal from untreated water. For better flow and lower pressure loss consider a pleated polyester sediment water filter. The pleats give the filter more surface area than a poly string wound or poly blown water filter.

For treated water you can use any of the filters mentioned previously, but there’s no reason to use anything other than pleated cellulose. As already mentioned, the pleats offer significantly greater surface area, thus higher flow with lower pressure loss. Pleated cellulose water filters are usually the prime choice for treated water. Lastly, I want to remember to mention RUSCO water filters. They are sediment filters made to remove large particulate over 75 microns. RUSCO’s are typically used as whole house water filters, and are also used to filter irrigation water to defend the sprinkler heads from sediment. More than anything, the RUSCO’s most famous feature is reusability. RUSCO’s are built with a flush valve to clean out the collected sediment. No filter changes, but they don’t work well with small sediment less than 75 microns.